Re: Consistency of Postulates of QM

[Bruce Kellett]

On 15/11/2017 1:18 am, Bruno Marchal wrote:

On 13 Nov 2017, at 22:40, Bruce Kellett wrote:

On 14/11/2017 2:07 am, Bruno Marchal wrote:

On 12 Nov 2017, at 23:05, Bruce Kellett wrote:

What really annoys me is the continued claim that many worlds 
eliminates the need for non-locality. It does not, and neither 
Bruno nor anyone else has ever produced a valid argument as to how 
many worlds might restore locality.


But nobody has proved that there is non locality in the MWI. 
EPR-BELL proves non-locality apparant in each branch, but the MWI 
avoids the needs of action at a distance to explains them. Once 
Alice and Bob are space-separated, their identity are independent. 
It makes no sense to talk of each of them like if they were related, 
(unless you correlate them with a third observer, etc) If they do 
measurement, some God could see that they are indeed no more 
related, but if they decide to come back to place where they can 
compared locally their spin, they will always get contact to the 
corresponding observer with the well correlated spin. The 
independent Alice and Bob will never meet because they can't belong 
to the same branch of the multiverse, by the MWI of the singlet 
state. So Mitra is right. Although Bertlmann's socks are tyically 
not working for Bell's violation in a MONO-universe, it works again 
in the MWI, applied in this case to the whole singlet state.


Bell has proved non-locality in MWI, every bit as much as in each 
branch separately. You appear not to have grasped the significance of 
the scenario I have argued carefully. Alice and Bob are not 
space-like separated in the scenario I outlined. Alice and Bob are 
together in the same laboratory when the second measurement is made. 
They are necessarily in the same world before, and branch in together 
according to Bob's result. Your mumbo-jumbo about them only being 
able to meet in appropriate matching branches does not work here, 
because they are always in the same branch. And there is no reason to 
suppose that their results in some of those branches do not violate 
conservation of angular momentum.


I have no clue what you mean. The singlet state guaranties the 
conservation of angular momentum in all worlds. The singlet state 
describes an infinity of "worlds",  and in each of them there is 
conservation of angular momentum, and it has a local common cause 
origin, the same in all worlds.


Tell me what you don't understand and I will attempt to explain it more 
clearly, as I did when Brent asked about the confusion of negatives in 
my final sentence above. (I meant that, given locality, there are 
branches in the above scenario that violate angular momentum conservation.)


Local common cause explanations (aka 'Bertlmann's socks') have been 
known not to give the correct quantum correlations since at least Bell's 
time.


Bruce

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Re: Consistency of Postulates of QM

[Brent Meeker]

On 11/14/2017 6:18 AM, Bruno Marchal wrote:


On 13 Nov 2017, at 22:40, Bruce Kellett wrote:


On 14/11/2017 2:07 am, Bruno Marchal wrote:

On 12 Nov 2017, at 23:05, Bruce Kellett wrote:

What really annoys me is the continued claim that many worlds 
eliminates the need for non-locality. It does not, and neither 
Bruno nor anyone else has ever produced a valid argument as to how 
many worlds might restore locality.


But nobody has proved that there is non locality in the MWI. 
EPR-BELL proves non-locality apparant in each branch, but the MWI 
avoids the needs of action at a distance to explains them. Once 
Alice and Bob are space-separated, their identity are independent. 
It makes no sense to talk of each of them like if they were related, 
(unless you correlate them with a third observer, etc) If they do 
measurement, some God could see that they are indeed no more 
related, but if they decide to come back to place where they can 
compared locally their spin, they will always get contact to the 
corresponding observer with the well correlated spin. The 
independent Alice and Bob will never meet because they can't belong 
to the same branch of the multiverse, by the MWI of the singlet 
state. So Mitra is right. Although Bertlmann's socks are tyically 
not working for Bell's violation in a MONO-universe, it works again 
in the MWI, applied in this case to the whole singlet state.


Bell has proved non-locality in MWI, every bit as much as in each 
branch separately. You appear not to have grasped the significance of 
the scenario I have argued carefully. Alice and Bob are not 
space-like separated in the scenario I outlined. Alice and Bob are 
together in the same laboratory when the second measurement is made. 
They are necessarily in the same world before, and branch in together 
according to Bob's result. Your mumbo-jumbo about them only being 
able to meet in appropriate matching branches does not work here, 
because they are always in the same branch. And there is no reason to 
suppose that their results in some of those branches do not violate 
conservation of angular momentum.


I have no clue what you mean. The singlet state guaranties the 
conservation of angular momentum in all worlds. The singlet state 
describes an infinity of "worlds",  and in each of them there is 
conservation of angular momentum, and it has a local common cause 
origin, the same in all worlds.


But it's not a sufficient 'hidden' variable to explain the space-like 
correlation of measurements.


Brent

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Re: Consistency of Postulates of QM

[agrayson2000]

On Monday, November 13, 2017 at 9:52:32 PM UTC-7, agrays...@gmail.com wrote:
>
>
>
> On Monday, November 13, 2017 at 9:38:54 PM UTC-7, agrays...@gmail.com 
> wrote:
>>
>>
>>
>> On Monday, November 13, 2017 at 4:22:08 PM UTC-7, John Clark wrote:
>>>
>>> On Mon, Nov 13, 2017 at 1:24 AM,  wrote ​
>>>
>>> ​> ​
 You're conflating Multiverse with the MWI.

>>>
>>> ​
>>> You can't have the MWI without the Multiverse, and if there is a 
>>> Multiverse then the MWI explains a lot.
>>> ​ ​
>>> There are about 10^80 atoms in the observable universe and obviously 
>>> there is a finite number of ways 10^80 atoms can be arranged in a sphere 
>>> with a radius of 13.8 billion light years; so if the 
>>> ​entire ​
>>> universe (not to be confused with the observable universe) is infinite 
>>> then at a very large but still finite distance things must repeat and there 
>>> is a universe identical to our own, and at another hyper large distance 
>>> there is a universe identical to ours except that the freckle on my right 
>>> thumb is on my left thumb instead. And at a even greater distance one 
>>> second after a John Clark hits send on a message identical to this one all 
>>> the air molecules in the room he is in go to the other side of the room due 
>>> to random thermal vibrations and that John Clark suffocates. Bizarre events 
>>> like that are not impossible just very very unlikely, but if the universe 
>>> is really infinite then everything that doesn't violate the laws of physics 
>>> will happen, and the Many World people say that's what the wave function is 
>>> trying to tell us, everything that can happen will happen.
>>>
>>
>> The concept of Multiverse and Many Worlds come from entirely different 
>> contexts and theories, so the idea that they are somehow connected or 
>> related strikes me a patently false. Moreover, the idea that if the 
>> universe is infinite (in some parameter; spatial extent, age, whatever), 
>> then anything that can happen, will happen, is IMO unproven and almost 
>> certainly false. For example, we know that irrational numbers exist, but in 
>> an infinite string of digits representing some irrational number, there are 
>> no repetitions of any subset strings. But there should be according to your 
>> conjecture.
>>
>
> *Or look at it this way; if your conjecture were true, it would be 
> impossible for irrational numbers to exist, since recurring repetitions of 
> subset strings would be impossible to avoid.*
>

I think my conjecture above is incorrect. Although finite strings of any 
length would repeat in an infinite random string, they would not repeat at 
regular intervals that would cause the original string to fail to represent 
an irrational number. OTOH, I think we can agree that necessary repetitions 
of whatever in a FINITE universe cannot be expected. Thus, if our universe 
is finite in extent and number of particles, there will be no automatic or 
expected repeats of anything. I submit that our universe is, indeed, finite 
(observable and unobservable regions) because it is FINITE IN AGE.

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Re: Consistency of Postulates of QM

[Bruno Marchal]

On 13 Nov 2017, at 22:40, agrayson2...@gmail.com wrote:




On Sunday, November 12, 2017 at 11:50:00 PM UTC-7,  
agrays...@gmail.com wrote:



On Sunday, November 12, 2017 at 11:24:15 PM UTC-7,  
agrays...@gmail.com wrote:



On Sunday, November 12, 2017 at 11:15:33 AM UTC-7, John Clark wrote:
On Sun, Nov 12, 2017 at 1:01 AM,  wrote:

​> ​What is your definition of non-realistic?

Nonrealistic means ​when something is not being observed it doesn't  
exist in any one definite state.​ ​


You have to be careful here. For example, when the Earth-Moon system  
formed, it existed in a definite state, but was NOT observed. So not  
everything in a definite state must be observed, by detectors or  
conscious entities. OTOH, when an electron is prepared for a double  
slit experiment, it is in a superposition of states; that is, NOT in  
a definite state. If it were in a definite state, we'd observe the  
classical probability distribution. So quantum experiments, and QM  
in general to the extent it relies on superposition of states, is  
NONREALISTIC, whereas the macro world is generally REALISTIC. I  
can't speak to why the macro world is realistic.


FWIW, I left out an important reason why some systems are in  
definite states, like macro systems, and others not, such as quantum  
systems prepared for measurements. It's likely related to whether  
the systems in question are ISOLATED.


If you find collapse of the wf anathema, instead of the MWI why not  
just assume the branches that aren't measured in this world,  
dissipate into the environment as I think Decoherence theory  
postulates?


In the MWI (= multiverse, = non-collapse), the dissipation is a (bad)  
terming for "entanglement with the environment".  If you have a  
superposition of some particle up + down, and that particle interact  
with some unknown passing particles, that you lost, from your point of  
view, the superposition is lost, as you would need the other particle  
to recover the interference of the initial particles. That is why it  
is hard to make macroscopic object interfere: they leak to easily to  
the environment, including to you, which is akin to a measurement. I  
use the expression "the superposition is contagious to the  
environment": the "dissipitation" is about the pure state, which  
behave like a mixed state when it has not been isolated enough.


Bruno





MWI doesn't tell us what will be measured in this or any other  
particular world, so what's the downside to this hugely simpler way  
of avoiding collapse?


A photon ​hits a horizontally polarizing filter and the universe  
splits in two if Many Worlds is right, in one the photon makes it  
through the filter and the inhabitants of that world conclude it is  
100% horizontally polarized , in the other world it doesn't get  
through the filter and they conclude it must have been 100%  
vertically polarized, but in the world before the split, before it  
hit the filter, the inhabitants of that world would conclude (if  
they believed in Many Worlds) that the photon did not have any one  
definite polarized state at all.


​​>> ​That is not unique to the MWI. In a accelerating  ​ 
Einsteinian universe such as ours energy is not conserved at the  
cosmological level.


​> ​There was some unique condition that gave rise to our  
universe.


​The multiverse may have always existed, if so then nothing, unique  
or otherwise, gave rise to it,​


You're conflating Multiverse with the MWI. In the former, OUR  
universe emerged due to unique, unknown initial conditions from an  
entity which, if it exists, is likely infinite in age and extent. In  
the MWI, universes allegedly emerge when Joe the Plumber shoots an  
electron at a slitted screen. The two situations are in no way  
comparable, and the latter seems hugely overblown IMO. So where the  
energy comes from in the MWI cannot be easily dismissed by the lack  
of global energy conservation in GR, or by referring to unknowns  
related to the emergence of our universe from a hypothetical  
Multiverse.



​> ​MWI has it happening wily-nily when someone performs a slit  
experiment in a lab (and uncountably many times). Hardly a  
conservative interpretation IMO.


​Many Worlds is very conservative if the mathematics doesn't  
say ​​anything about a wave collapse. And it doesn't.


​>> ​they can't even say what is observation is. ​

​> ​I can. They can. In a SG experiment, e.g., an observation  
occurs when the electron's spin state is aligned, or anti-aligned to  
the magnetic field.


​Observation is the wrong word if no observer is involved, then its  
just a change and a change is the criteria Many Worlds uses.


Agreed that "observation" is misleading when there is no  
consciousness involved in a quantum experiment. We should speak of  
detectable changes recorded by instruments; aka "measurements".


In MWI everything that can happen does happen, so when a photon  
approaches 2 slits the 

Re: Consistency of Postulates of QM

[Bruno Marchal]

On 13 Nov 2017, at 22:40, Bruce Kellett wrote:


On 14/11/2017 2:07 am, Bruno Marchal wrote:

On 12 Nov 2017, at 23:05, Bruce Kellett wrote:

What really annoys me is the continued claim that many worlds  
eliminates the need for non-locality. It does not, and neither  
Bruno nor anyone else has ever produced a valid argument as to how  
many worlds might restore locality.


But nobody has proved that there is non locality in the MWI. EPR- 
BELL proves non-locality apparant in each branch, but the MWI  
avoids the needs of action at a distance to explains them. Once  
Alice and Bob are space-separated, their identity are independent.  
It makes no sense to talk of each of them like if they were  
related, (unless you correlate them with a third observer, etc) If  
they do measurement, some God could see that they are indeed no  
more related, but if they decide to come back to place where they  
can compared locally their spin, they will always get contact to  
the corresponding observer with the well correlated spin. The  
independent Alice and Bob will never meet because they can't belong  
to the same branch of the multiverse, by the MWI of the singlet  
state. So Mitra is right. Although Bertlmann's socks are tyically  
not working for Bell's violation in a MONO-universe, it works again  
in the MWI, applied in this case to the whole singlet state.


Bell has proved non-locality in MWI, every bit as much as in each  
branch separately. You appear not to have grasped the significance  
of the scenario I have argued carefully. Alice and Bob are not space- 
like separated in the scenario I outlined. Alice and Bob are  
together in the same laboratory when the second measurement is made.  
They are necessarily in the same world before, and branch in  
together according to Bob's result. Your mumbo-jumbo about them only  
being able to meet in appropriate matching branches does not work  
here, because they are always in the same branch. And there is no  
reason to suppose that their results in some of those branches do  
not violate conservation of angular momentum.


I have no clue what you mean. The singlet state guaranties the  
conservation of angular momentum in all worlds. The singlet state  
describes an infinity of "worlds",  and in each of them there is  
conservation of angular momentum, and it has a local common cause  
origin, the same in all worlds.


Bruno






Bruce

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http://iridia.ulb.ac.be/~marchal/



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Re: Consistency of Postulates of QM

[Stathis Papaioannou]

On Mon, 13 Nov 2017 at 8:54 am, Bruce Kellett 
wrote:

>
> I don't think you have fully understood the scenario I have outlined.
> There is no collapse, many worlds is assumed throughout. Alice splits
> according to her measurement result. Both copies of Alice go to meet
> Bob, carrying the other particle of the original pair. Since they both
> have now met Bob, the split that Alice occasioned has now spread to
> entangle Bob as well as the rest of her environment. So there are now
> two worlds, each of which has a copy of Bob, and an Alice, who has a
> particular result. Locality says that Bob's particle is unchanged from
> production, so when he measure its spin, he splits into two copies,
> according to spin up or spin down. Since Alice is standing beside him,
> she also becomes entangled with his result. But Alice already has a
> definite result in each branch, so we now have four branches: with
> results 'up-up', 'up-down', 'down-up', and 'down-down'. However, only
> the 'up-down' and 'down-up' branches conserve angular momentum. How do
> you rule out the other branches?


When you put something in the cupboard and come back later to get it, why,
under MWI, is it still there?

> --
Stathis Papaioannou

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Re: Consistency of Postulates of QM

[smitra]

On 14-11-2017 09:23, Bruce Kellett wrote:

On 14/11/2017 5:51 pm, smitra wrote:

On 13-11-2017 03:52, Bruce Kellett wrote:

On 13/11/2017 12:15 pm, smitra wrote:

On 12-11-2017 22:54, Bruce Kellett wrote:

On 13/11/2017 7:19 am, smitra wrote:

On 12-11-2017 11:21, Bruce Kellett wrote:

On 12/11/2017 9:14 pm, smitra wrote:

On 12-11-2017 07:57, Bruce Kellett wrote:

On 12/11/2017 5:39 pm, Brent Meeker wrote:

In Bruno's model the "influence at a distance" is determing 
which

world you're in.


 If that means anything at all, it is still non-local because 
Bruno
has to rule out the worlds in which angular momentum is not 
conserved;
 he has not shown how he can do this. If it is simply that you 
cannot
find yourself in a world in which AM is not conserved, then 
that is
just an unabashed appeal to magic, since such worlds have not 
been

shown not to exist.

 Bruce


There are two correlated copies of Alice and Bob induced by the 
correlated spins, there is nothing nonlocal about that in the 
MWI. There is only a non- locality problem here if you assume a 
collapse interpretation of QM. In the MWI the correlation arises 
via an originally local common cause.


There is no collapse assumption in anything that I have written 
about
this scenario. What is the local common cause in MWI? Is that a 
local
hidden variable? Such would work in the time-like case, but not 
in

general -- that is Bell's result.

But you have still not answered the fundamental question as to 
what
causes Bob to necessarily measure spin down when Alice joins him 
with
a spin-up result? What turns Bob's particle from an unpolarized 
to a
polarized state so that the probabilities change from 50/50 to 
100%

for spin down?

Bruce


Bob's particle never changed due to anything Alice did in the MWI.


Right.

All that happened was that Alice got entangled with her particle 
(and not just Alice,  her entire environment gets entangled with 
the state of her particle), which in turn was entangled with Bob's 
particle. So, Bob has the same probabilities for finding spin up 
or down,


Right. In fact, when Alice_up meets Bob, and Alice_down meets Bob 
in

the parallel universe, they can both tell Bob their result, and the
direction in which they measured the spin. This makes no 
difference,

since Bob is now entangled with the Alice's that have definite
results. None of this makes any difference to the particle Bob
measures, because, by the definition of locality, nothing has
interacted with Bob's particle, so it must be in the same spin 
state

as when it was produced.


except that he can now measure the state of his particle by 
performing a measurement on Alice,  by asking her what she found 
for her spin.


That is not a measurement, that is making a prediction based on the
conservation of angular momentum.

It's not true that before Bob knows what Alice has found that only 
one of the two version's of Alice has arrived and that the 
information of her spin state is then already present in Bob's 
sector. This is not true in the MWI, decoherence simple means that 
you can't demonstrate the existence of the two versions of Alice 
via an interference experiment. But the inability to do so, 
doesn't by itself imply that only one version really exists.


I don't think you have fully understood the scenario I have 
outlined.
There is no collapse, many worlds is assumed throughout. Alice 
splits
according to her measurement result. Both copies of Alice go to 
meet
Bob, carrying the other particle of the original pair. Since they 
both

have now met Bob, the split that Alice occasioned has now spread to
entangle Bob as well as the rest of her environment. So there are 
now
two worlds, each of which has a copy of Bob, and an Alice, who has 
a
particular result. Locality says that Bob's particle is unchanged 
from

production, so when he measure its spin, he splits into two copies,
according to spin up or spin down. Since Alice is standing beside 
him,

she also becomes entangled with his result. But Alice already has a
definite result in each branch, so we now have four branches: with
results 'up-up', 'up-down', 'down-up', and 'down-down'. However, 
only
the 'up-down' and 'down-up' branches conserve angular momentum. How 
do

you rule out the other branches?

Bruce


The splitting as an apparent nonlocal aspect to it, which is due to 
a common cause effect, the spins were entangled, and that 
entanglement happened when the spins were created due to a local 
interaction in the past.


Yes, the entangled spin zero state was created in the past.

If you then let Alice and Bob measure the space-like separated 
spins, they'll split up, and that happens in a correlated way, 
because the spins are correlated. It is just the MWI variant of 
Bertlmann's socks


That is not correct. The correlation you seems to be relying on is
non-local once the particles have separated. As Bell pointed out,
Bertlmann's socks are the wrong way to look at it! Besides, my

Re: Consistency of Postulates of QM

[Bruce Kellett]

On 14/11/2017 5:51 pm, smitra wrote:

On 13-11-2017 03:52, Bruce Kellett wrote:

On 13/11/2017 12:15 pm, smitra wrote:

On 12-11-2017 22:54, Bruce Kellett wrote:

On 13/11/2017 7:19 am, smitra wrote:

On 12-11-2017 11:21, Bruce Kellett wrote:

On 12/11/2017 9:14 pm, smitra wrote:

On 12-11-2017 07:57, Bruce Kellett wrote:

On 12/11/2017 5:39 pm, Brent Meeker wrote:


In Bruno's model the "influence at a distance" is determing which
world you're in.


 If that means anything at all, it is still non-local because 
Bruno
has to rule out the worlds in which angular momentum is not 
conserved;
 he has not shown how he can do this. If it is simply that you 
cannot
find yourself in a world in which AM is not conserved, then 
that is

just an unabashed appeal to magic, since such worlds have not been
shown not to exist.

 Bruce


There are two correlated copies of Alice and Bob induced by the 
correlated spins, there is nothing nonlocal about that in the 
MWI. There is only a non- locality problem here if you assume a 
collapse interpretation of QM. In the MWI the correlation arises 
via an originally local common cause.


There is no collapse assumption in anything that I have written 
about
this scenario. What is the local common cause in MWI? Is that a 
local

hidden variable? Such would work in the time-like case, but not in
general -- that is Bell's result.

But you have still not answered the fundamental question as to what
causes Bob to necessarily measure spin down when Alice joins him 
with

a spin-up result? What turns Bob's particle from an unpolarized to a
polarized state so that the probabilities change from 50/50 to 100%
for spin down?

Bruce


Bob's particle never changed due to anything Alice did in the MWI.


Right.

All that happened was that Alice got entangled with her particle 
(and not just Alice,  her entire environment gets entangled with 
the state of her particle), which in turn was entangled with Bob's 
particle. So, Bob has the same probabilities for finding spin up 
or down,


Right. In fact, when Alice_up meets Bob, and Alice_down meets Bob in
the parallel universe, they can both tell Bob their result, and the
direction in which they measured the spin. This makes no difference,
since Bob is now entangled with the Alice's that have definite
results. None of this makes any difference to the particle Bob
measures, because, by the definition of locality, nothing has
interacted with Bob's particle, so it must be in the same spin state
as when it was produced.


except that he can now measure the state of his particle by 
performing a measurement on Alice,  by asking her what she found 
for her spin.


That is not a measurement, that is making a prediction based on the
conservation of angular momentum.

It's not true that before Bob knows what Alice has found that only 
one of the two version's of Alice has arrived and that the 
information of her spin state is then already present in Bob's 
sector. This is not true in the MWI, decoherence simple means that 
you can't demonstrate the existence of the two versions of Alice 
via an interference experiment. But the inability to do so, 
doesn't by itself imply that only one version really exists.


I don't think you have fully understood the scenario I have outlined.
There is no collapse, many worlds is assumed throughout. Alice splits
according to her measurement result. Both copies of Alice go to meet
Bob, carrying the other particle of the original pair. Since they both
have now met Bob, the split that Alice occasioned has now spread to
entangle Bob as well as the rest of her environment. So there are now
two worlds, each of which has a copy of Bob, and an Alice, who has a
particular result. Locality says that Bob's particle is unchanged from
production, so when he measure its spin, he splits into two copies,
according to spin up or spin down. Since Alice is standing beside him,
she also becomes entangled with his result. But Alice already has a
definite result in each branch, so we now have four branches: with
results 'up-up', 'up-down', 'down-up', and 'down-down'. However, only
the 'up-down' and 'down-up' branches conserve angular momentum. How do
you rule out the other branches?

Bruce


The splitting as an apparent nonlocal aspect to it, which is due to 
a common cause effect, the spins were entangled, and that 
entanglement happened when the spins were created due to a local 
interaction in the past.


Yes, the entangled spin zero state was created in the past.

If you then let Alice and Bob measure the space-like separated 
spins, they'll split up, and that happens in a correlated way, 
because the spins are correlated. It is just the MWI variant of 
Bertlmann's socks


That is not correct. The correlation you seems to be relying on is
non-local once the particles have separated. As Bell pointed out,
Bertlmann's socks are the wrong way to look at it! Besides, my
variation was to look at time-like separated measurements so that one

Re: Consistency of Postulates of QM

[smitra]

On 13-11-2017 03:52, Bruce Kellett wrote:

On 13/11/2017 12:15 pm, smitra wrote:

On 12-11-2017 22:54, Bruce Kellett wrote:

On 13/11/2017 7:19 am, smitra wrote:

On 12-11-2017 11:21, Bruce Kellett wrote:

On 12/11/2017 9:14 pm, smitra wrote:

On 12-11-2017 07:57, Bruce Kellett wrote:

On 12/11/2017 5:39 pm, Brent Meeker wrote:

In Bruno's model the "influence at a distance" is determing 
which

world you're in.


 If that means anything at all, it is still non-local because 
Bruno
has to rule out the worlds in which angular momentum is not 
conserved;
 he has not shown how he can do this. If it is simply that you 
cannot
find yourself in a world in which AM is not conserved, then that 
is
just an unabashed appeal to magic, since such worlds have not 
been

shown not to exist.

 Bruce


There are two correlated copies of Alice and Bob induced by the 
correlated spins, there is nothing nonlocal about that in the MWI. 
There is only a non- locality problem here if you assume a 
collapse interpretation of QM. In the MWI the correlation arises 
via an originally local common cause.


There is no collapse assumption in anything that I have written 
about
this scenario. What is the local common cause in MWI? Is that a 
local

hidden variable? Such would work in the time-like case, but not in
general -- that is Bell's result.

But you have still not answered the fundamental question as to what
causes Bob to necessarily measure spin down when Alice joins him 
with
a spin-up result? What turns Bob's particle from an unpolarized to 
a

polarized state so that the probabilities change from 50/50 to 100%
for spin down?

Bruce


Bob's particle never changed due to anything Alice did in the MWI.


Right.

All that happened was that Alice got entangled with her particle 
(and not just Alice,  her entire environment gets entangled with the 
state of her particle), which in turn was entangled with Bob's 
particle. So, Bob has the same probabilities for finding spin up or 
down,


Right. In fact, when Alice_up meets Bob, and Alice_down meets Bob in
the parallel universe, they can both tell Bob their result, and the
direction in which they measured the spin. This makes no difference,
since Bob is now entangled with the Alice's that have definite
results. None of this makes any difference to the particle Bob
measures, because, by the definition of locality, nothing has
interacted with Bob's particle, so it must be in the same spin state
as when it was produced.


except that he can now measure the state of his particle by 
performing a measurement on Alice,  by asking her what she found for 
her spin.


That is not a measurement, that is making a prediction based on the
conservation of angular momentum.

It's not true that before Bob knows what Alice has found that only 
one of the two version's of Alice has arrived and that the 
information of her spin state is then already present in Bob's 
sector. This is not true in the MWI, decoherence simple means that 
you can't demonstrate the existence of the two versions of Alice via 
an interference experiment. But the inability to do so, doesn't by 
itself imply that only one version really exists.


I don't think you have fully understood the scenario I have outlined.
There is no collapse, many worlds is assumed throughout. Alice splits
according to her measurement result. Both copies of Alice go to meet
Bob, carrying the other particle of the original pair. Since they 
both

have now met Bob, the split that Alice occasioned has now spread to
entangle Bob as well as the rest of her environment. So there are now
two worlds, each of which has a copy of Bob, and an Alice, who has a
particular result. Locality says that Bob's particle is unchanged 
from

production, so when he measure its spin, he splits into two copies,
according to spin up or spin down. Since Alice is standing beside 
him,

she also becomes entangled with his result. But Alice already has a
definite result in each branch, so we now have four branches: with
results 'up-up', 'up-down', 'down-up', and 'down-down'. However, only
the 'up-down' and 'down-up' branches conserve angular momentum. How 
do

you rule out the other branches?

Bruce


The splitting as an apparent nonlocal aspect to it, which is  due to a 
common cause effect, the spins were entangled, and that entanglement 
happened when the spins were created due to a local interaction in the 
past.


Yes, the entangled spin zero state was created in the past.

If you then let Alice and Bob measure the space-like separated spins, 
they'll split up, and that happens in a correlated way, because the 
spins are correlated. It is just the MWI variant of Bertlmann's socks


That is not correct. The correlation you seems to be relying on is
non-local once the particles have separated. As Bell pointed out,
Bertlmann's socks are the wrong way to look at it! Besides, my
variation was to look at time-like separated measurements so that one
could keep explicit track of 

Re: Consistency of Postulates of QM

[agrayson2000]

On Monday, November 13, 2017 at 10:46:23 PM UTC-7, Brent wrote:
>
>
>
> On 11/13/2017 8:25 PM, agrays...@gmail.com  wrote:
>
>
>
> On Monday, November 13, 2017 at 4:22:08 PM UTC-7, John Clark wrote: 
>>
>> On Mon, Nov 13, 2017 at 1:24 AM,  wrote:
>>
>> ​> 
> ​>> ​
> ​
> What is your definition of non-realistic? 
>

 ​>> ​
 Nonrealistic means ​when something is not being observed it doesn't 
 exist in any one definite state.​
   
 ​ 

>>>
>>> ​> ​
>>> You have to be careful here. For example, when the Earth-Moon system 
>>> formed, it existed in a definite state, but was NOT observed.
>>>
>>
>> ​That's just stating as a fact the​ very thing we're debating. Was the 
>> Earth-Moon ever in one definite state? If MWI is right the answer is no, it 
>> was always in a huge number of states, every state that was not forbidden 
>> by the laws of physics. If Copenhagen is right then Earth-Moon system was 
>> in no state at all for billions of years until somebody made a measurement 
>> and the fuzziness collapsed into one sharp definite state. Exactly what 
>> does and does not constitutes a measurement the Copenhagen people leave 
>> as a exercise for the reader.
>>
>
> Brent can correct me if I am wrong, but I think every macro system, 
> although comprised of a huge number of individual constituents, is in one 
> definite state; namely, the combined states of its constituents, and this 
> is because each constituent state has interacted with the environment. That 
> is, the lack of ISOLATION is the condition for the existence of this macro 
> definite state. OTOH, when, say, electrons are prepared for a slit 
> experiment, they are ISOLATED, and this gives rise to the superposition of 
> states, which is where the system is NOT in any definite state of the 
> states comprising the superposition. 
>
>
> This is looking at it wrong.  A superposition is a definite state, it's 
> just not an eigenstate of the basis you've chosen. 
>
 
I like that formulation. I was reacting to Clark's comment that a system in 
a superposition of states is not in any state comprising the superposition, 
and thus, in this context, contradicted REALISM.
.  

> I'd say a macroscopic object is never in a (knowable) definite state 
> because it's continually interacting with the rest of the environment.  The 
> Bucky Ball experiment shows that even radiating some IR photons in enough 
> to destroy interference effects.  So macroscopic objects have definite 
> (FAPP) states in the classical sense, but that's not the same as a ray in 
> Hilbert space.
>

I meant that any macro state is definite, albeit always fluctuating. Not in 
a superposition.

>
> Brent
>
> Thus, if I am correct, the Earth-Moon system was, indeed, in a definite 
> state when it formed, even though there were no "observers" of any type to 
> witness it. I contend that your understanding of what's necessary for an 
> "event" to exist or occur, is seriously incorrect. 
>
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Re: Consistency of Postulates of QM

[Brent Meeker]

On 11/13/2017 8:25 PM, agrayson2...@gmail.com wrote:



On Monday, November 13, 2017 at 4:22:08 PM UTC-7, John Clark wrote:

On Mon, Nov 13, 2017 at 1:24 AM, wrote:

​>
​>> ​
​
What is your definition of non-realistic?


​>> ​
Nonrealistic means ​when something is not being observed
it doesn't exist in any one definite state.​
​


​> ​
You have to be careful here. For example, when the Earth-Moon
system formed, it existed in a definite state, but was NOT
observed.


​That's just stating as a fact the​ very thing we're debating. Was
the Earth-Moon ever in one definite state? If MWI is right the
answer is no, it was always in a huge number of states, every
state that was not forbidden by the laws of physics. If Copenhagen
is right then Earth-Moon system was in no state at all for
billions of years until somebody made a measurement and the
fuzziness collapsed into one sharp definite state. Exactly what
does and does not constitutes a measurement the Copenhagen people
leave as a exercise for the reader.


Brent can correct me if I am wrong, but I think every macro system, 
although comprised of a huge number of individual constituents, is in 
one definite state; namely, the combined states of its constituents, 
and this is because each constituent state has interacted with the 
environment. That is, the lack of ISOLATION is the condition for the 
existence of this macro definite state. OTOH, when, say, electrons are 
prepared for a slit experiment, they are ISOLATED, and this gives rise 
to the superposition of states, which is where the system is NOT in 
any definite state of the states comprising the superposition.


This is looking at it wrong.  A superposition is a definite state, it's 
just not an eigenstate of the basis you've chosen.  I'd say a 
macroscopic object is never in a (knowable) definite state because it's 
continually interacting with the rest of the environment.  The Bucky 
Ball experiment shows that even radiating some IR photons in enough to 
destroy interference effects.  So macroscopic objects have definite 
(FAPP) states in the classical sense, but that's not the same as a ray 
in Hilbert space.


Brent

Thus, if I am correct, the Earth-Moon system was, indeed, in a 
definite state when it formed, even though there were no "observers" 
of any type to witness it. I contend that your understanding of what's 
necessary for an "event" to exist or occur, is seriously incorrect.


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Re: Consistency of Postulates of QM

[agrayson2000]

On Monday, November 13, 2017 at 9:38:54 PM UTC-7, agrays...@gmail.com wrote:
>
>
>
> On Monday, November 13, 2017 at 4:22:08 PM UTC-7, John Clark wrote:
>>
>> On Mon, Nov 13, 2017 at 1:24 AM,  wrote ​
>>
>> ​> ​
>>> You're conflating Multiverse with the MWI.
>>>
>>
>> ​
>> You can't have the MWI without the Multiverse, and if there is a 
>> Multiverse then the MWI explains a lot.
>> ​ ​
>> There are about 10^80 atoms in the observable universe and obviously 
>> there is a finite number of ways 10^80 atoms can be arranged in a sphere 
>> with a radius of 13.8 billion light years; so if the 
>> ​entire ​
>> universe (not to be confused with the observable universe) is infinite 
>> then at a very large but still finite distance things must repeat and there 
>> is a universe identical to our own, and at another hyper large distance 
>> there is a universe identical to ours except that the freckle on my right 
>> thumb is on my left thumb instead. And at a even greater distance one 
>> second after a John Clark hits send on a message identical to this one all 
>> the air molecules in the room he is in go to the other side of the room due 
>> to random thermal vibrations and that John Clark suffocates. Bizarre events 
>> like that are not impossible just very very unlikely, but if the universe 
>> is really infinite then everything that doesn't violate the laws of physics 
>> will happen, and the Many World people say that's what the wave function is 
>> trying to tell us, everything that can happen will happen.
>>
>
> The concept of Multiverse and Many Worlds come from entirely different 
> contexts and theories, so the idea that they are somehow connected or 
> related strikes me a patently false. Moreover, the idea that if the 
> universe is infinite (in some parameter; spatial extent, age, whatever), 
> then anything that can happen, will happen, is IMO unproven and almost 
> certainly false. For example, we know that irrational numbers exist, but in 
> an infinite string of digits representing some irrational number, there are 
> no repetitions of any subset strings. But there should be according to your 
> conjecture.
>

*Or look at it this way; if your conjecture were true, it would be 
impossible for irrational numbers to exist, since recurring repetitions of 
subset strings would be impossible to avoid.*

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Re: Consistency of Postulates of QM

[agrayson2000]

On Monday, November 13, 2017 at 4:22:08 PM UTC-7, John Clark wrote:
>
> On Mon, Nov 13, 2017 at 1:24 AM,  wrote
>  ​
>
> ​> ​
>> You're conflating Multiverse with the MWI.
>>
>
> ​
> You can't have the MWI without the Multiverse, and if there is a 
> Multiverse then the MWI explains a lot.
> ​ ​
> There are about 10^80 atoms in the observable universe and obviously there 
> is a finite number of ways 10^80 atoms can be arranged in a sphere with a 
> radius of 13.8 billion light years; so if the 
> ​entire ​
> universe (not to be confused with the observable universe) is infinite 
> then at a very large but still finite distance things must repeat and there 
> is a universe identical to our own, and at another hyper large distance 
> there is a universe identical to ours except that the freckle on my right 
> thumb is on my left thumb instead. And at a even greater distance one 
> second after a John Clark hits send on a message identical to this one all 
> the air molecules in the room he is in go to the other side of the room due 
> to random thermal vibrations and that John Clark suffocates. Bizarre events 
> like that are not impossible just very very unlikely, but if the universe 
> is really infinite then everything that doesn't violate the laws of physics 
> will happen, and the Many World people say that's what the wave function is 
> trying to tell us, everything that can happen will happen.
>

The concept of Multiverse and Many Worlds come from entirely different 
contexts and theories, so the idea that they are somehow connected or 
related strikes me a patently false. Moreover, the idea that if the 
universe is infinite (in some parameter; spatial extent, age, whatever), 
then anything that can happen, will happen, is IMO unproven and almost 
certainly false. For example, we know that irrational numbers exist, but in 
an infinite string of digits representing some irrational number, there are 
no repetitions of any subset strings. But there should be according to your 
conjecture.

>

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Re: Consistency of Postulates of QM

[agrayson2000]

On Monday, November 13, 2017 at 4:22:08 PM UTC-7, John Clark wrote:
>
> On Mon, Nov 13, 2017 at 1:24 AM,  
> wrote:
>
> ​> 
 ​>> ​
 ​
 What is your definition of non-realistic? 

>>>
>>> ​>> ​
>>> Nonrealistic means ​when something is not being observed it doesn't 
>>> exist in any one definite state.​
>>>  
>>> ​ 
>>>
>>
>> ​> ​
>> You have to be careful here. For example, when the Earth-Moon system 
>> formed, it existed in a definite state, but was NOT observed.
>>
>
> ​That's just stating as a fact the​ very thing we're debating. Was the 
> Earth-Moon ever in one definite state? If MWI is right the answer is no, it 
> was always in a huge number of states, every state that was not forbidden 
> by the laws of physics. If Copenhagen is right then Earth-Moon system was 
> in no state at all for billions of years until somebody made a measurement 
> and the fuzziness collapsed into one sharp definite state. Exactly what 
> does and does not constitutes a measurement the Copenhagen people leave 
> as a exercise for the reader.
>

Brent can correct me if I am wrong, but I think every macro system, 
although comprised of a huge number of individual constituents, is in one 
definite state; namely, the combined states of its constituents, and this 
is because each constituent state has interacted with the environment. That 
is, the lack of ISOLATION is the condition for the existence of this macro 
definite state. OTOH, when, say, electrons are prepared for a slit 
experiment, they are ISOLATED, and this gives rise to the superposition of 
states, which is where the system is NOT in any definite state of the 
states comprising the superposition. Thus, if I am correct, the Earth-Moon 
system was, indeed, in a definite state when it formed, even though there 
were no "observers" of any type to witness it. I contend that your 
understanding of what's necessary for an "event" to exist or occur, is 
seriously incorrect. 

>

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Re: Consistency of Postulates of QM

[John Clark]

On Mon, Nov 13, 2017 at 8:01 PM,  wrote:

​> ​
> How is everything except one value in this world (the others dissipating
> into the environment), WORSE than conjuring a multitude of universes for
> the other values to be measured?
>

​One theory makes an assumption and the other, being more conservative,
does not.​



> ​> ​
> When you pull a slot machine, is it really conservative to assert 10
> million other universes come into being (along with the player!) for the
> other unrealized outcomes in this universe?
>

​If the universe is really infinite, not just very very big but INFINITE,
then somewhere in that infinite universe there must be a collection of
atoms that behaves in a Johnkclarkian way that observes every one of the 10
million states a slot machine can be in; and that's more than just
conservative, there is no other way it could be.

 And if the multiverse is infinite then it wouldn't be a case of a branch
coming into being but of determining which branch a rational observer is
in. Based on known information many worlds assigns a complex number to
every branch and the degree of certainty a rational agent would have for
believing to be in that branch can be obtained by squaring the absolute
value of that complex number. This is called The Born Rule.

​> ​
> By replacing Decoherence with MWI seems to raise hugely more insoluble
> problems than simply using the Decoherence model of dissipation of the
> unrealized outcomes.
>

​You're assuming there actually are unrealized outcomes, its true you can
only see one outcome but that's exactly what is to be expected if you are
duplicated along ​with all those other other outcomes. The point is you
can't explain why they dissipate, Many Worlds can't explain it either but
it doesn't need to because it says there are no
unrealized outcomes
​.

 John K Clark​

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Re: Consistency of Postulates of QM

[Brent Meeker]

On 11/13/2017 5:01 PM, agrayson2...@gmail.com wrote:



On Monday, November 13, 2017 at 4:41:02 PM UTC-7, John Clark wrote:

On Mon, Nov 13, 2017 at 4:40 PM, wrote:

*
​> ​
If you find collapse of the wf anathema, instead of the MWI
why not just assume the branches that aren't measured in this
world, dissipate into the environment as I think Decoherence
theory postulates?  MWI doesn't tell us what will be measured
in this or any other particular world, so what's the downside
to this hugely simpler way of avoiding collapse?*


​How is everything except one value dissipating any different from
everything collapsing into one value?



How is everything except one value in this world (the others 
dissipating into the environment), WORSE than conjuring a multitude of 
universes for the other values to be measured? I fail to see anything 
"conservative" about this pov. When you pull a slot machine, is it 
really conservative to assert 10 million other universes come into 
being (along with the player!) for the other unrealized outcomes in 
this universe?


And what does nature consider to be a measurement and what does it
not? A change is simpler than a measurement and a theory without
an assumption is simpler than a theory that needs an assumption. I
say we don't really need an assumption of collapse (or
dissipation) so get rid of it.


By replacing Decoherence with MWI seems to raise hugely more insoluble 
problems than simply using the Decoherence model of dissipation of the 
unrealized outcomes.


Decoherence implies small cross terms in the density matrix (which 
implies small measure in the given basis) but it doesn't say anything 
about "dissipating" the diagonal terms that represent possible outcomes.


Brent

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Re: Consistency of Postulates of QM

[agrayson2000]

On Monday, November 13, 2017 at 4:41:02 PM UTC-7, John Clark wrote:
>
> On Mon, Nov 13, 2017 at 4:40 PM,  
> wrote:
>
> *​> ​If you find collapse of the wf anathema, instead of the MWI why not 
>> just assume the branches that aren't measured in this world, dissipate into 
>> the environment as I think Decoherence theory postulates?  MWI doesn't tell 
>> us what will be measured in this or any other particular world, so what's 
>> the downside to this hugely simpler way of avoiding collapse?*
>>
>
> ​How is everything except one value dissipating any different from 
> everything collapsing into one value? 
>


How is everything except one value in this world (the others dissipating 
into the environment), WORSE than conjuring a multitude of universes for 
the other values to be measured? I fail to see anything "conservative" 
about this pov. When you pull a slot machine, is it really conservative to 
assert 10 million other universes come into being (along with the player!) 
for the other unrealized outcomes in this universe?
 

> And what does nature consider to be a measurement and what does it not? A 
> change is simpler than a measurement and a theory without an assumption is 
> simpler than a theory that needs an assumption. I say we don't really need 
> an assumption of collapse (or dissipation) so get rid of it.
>

By replacing Decoherence with MWI seems to raise hugely more insoluble 
problems than simply using the Decoherence model of dissipation of the 
unrealized outcomes. 

>
> John K Clark
>
> ​
>  
>
>>  
>>
>
>
>


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Re: Consistency of Postulates of QM

[John Clark]

On Mon, Nov 13, 2017 at 4:40 PM,  wrote:

*​> ​If you find collapse of the wf anathema, instead of the MWI why not
> just assume the branches that aren't measured in this world, dissipate into
> the environment as I think Decoherence theory postulates?  MWI doesn't tell
> us what will be measured in this or any other particular world, so what's
> the downside to this hugely simpler way of avoiding collapse?*
>

​How is everything except one value dissipating any different from
everything collapsing into one value? And what does nature consider to be a
measurement and what does it not? A change is simpler than a measurement
and a theory without an assumption is simpler than a theory that needs an
assumption. I say we don't really need an assumption of collapse (or
dissipation) so get rid of it.

John K Clark

​


>
>



>>>

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Re: Consistency of Postulates of QM

[Bruce Kellett]

On 14/11/2017 10:01 am, Brent Meeker wrote:

On 11/13/2017 1:40 PM, Bruce Kellett wrote:

On 14/11/2017 2:07 am, Bruno Marchal wrote:

On 12 Nov 2017, at 23:05, Bruce Kellett wrote:

What really annoys me is the continued claim that many worlds 
eliminates the need for non-locality. It does not, and neither 
Bruno nor anyone else has ever produced a valid argument as to how 
many worlds might restore locality.


But nobody has proved that there is non locality in the MWI. 
EPR-BELL proves non-locality apparant in each branch, but the MWI 
avoids the needs of action at a distance to explains them. Once 
Alice and Bob are space-separated, their identity are independent. 
It makes no sense to talk of each of them like if they were related, 
(unless you correlate them with a third observer, etc) If they do 
measurement, some God could see that they are indeed no more 
related, but if they decide to come back to place where they can 
compared locally their spin, they will always get contact to the 
corresponding observer with the well correlated spin. The 
independent Alice and Bob will never meet because they can't belong 
to the same branch of the multiverse, by the MWI of the singlet 
state. So Mitra is right. Although Bertlmann's socks are tyically 
not working for Bell's violation in a MONO-universe, it works again 
in the MWI, applied in this case to the whole singlet state.


Bell has proved non-locality in MWI, every bit as much as in each 
branch separately. You appear not to have grasped the significance of 
the scenario I have argued carefully. Alice and Bob are not 
space-like separated in the scenario I outlined. Alice and Bob are 
together in the same laboratory when the second measurement is made. 
They are necessarily in the same world before, and branch in together 
according to Bob's result. Your mumbo-jumbo about them only being 
able to meet in appropriate matching branches does not work here, 
because they are always in the same branch. And there is no reason to 
suppose that their results in some of those branches do not violate 
conservation of angular momentum.


It's that last point I don't understand.  Why isn't conservation of 
angular momentum a condition in every world.  It's something separate 
from QM.


Yes, sorry, I seem to have got my negatives confused! There is no reason 
to suppose (in the time-like case proposed) that 'up-up' or 'down-down' 
combinations are impossible, and such combinations of results would 
violate conservation of angular momentum.


I'd say there is non-locality even when Bob's measurement is time-like 
because there is correlation with no physical causal link.   The 
"common cause" of conserved angular momentum is not an explanation 
because that doesn't work in the space-like case and there's no reason 
to suppose QM is different in the two cases.


You are quite right here. The time-like and space-like separated 
measurements must give the same results, and have the same explanation. 
Common cause explanations don't work because space-like separations rule 
them out. My reason for considering time-like separation is that in that 
case one can precisely control the number of branches of the MWI 
involved, so that Alice and Bob are in the same branch when the crucial 
measurement is made. Thus there is no confusion over separate worlds 
that have to be matched up according to AM conservation when they 
finally meet -- they are always together, so there is no 'matching up' 
issue.


Bruce

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Re: Consistency of Postulates of QM

[John Clark]

On Mon, Nov 13, 2017 at 1:24 AM,  wrote:

​>
>>> ​>> ​
>>> ​
>>> What is your definition of non-realistic?
>>>
>>
>> ​>> ​
>> Nonrealistic means ​when something is not being observed it doesn't exist
>> in any one definite state.​
>>
>> ​
>>
>
> ​> ​
> You have to be careful here. For example, when the Earth-Moon system
> formed, it existed in a definite state, but was NOT observed.
>

​That's just stating as a fact the​ very thing we're debating. Was the
Earth-Moon ever in one definite state? If MWI is right the answer is no, it
was always in a huge number of states, every state that was not forbidden
by the laws of physics. If Copenhagen is right then Earth-Moon system was
in no state at all for billions of years until somebody made a measurement
and the fuzziness collapsed into one sharp definite state. Exactly what
does and does not constitutes a measurement the Copenhagen people leave as
a exercise for the reader.


> ​> ​
> OTOH, when an electron is prepared for a double slit experiment, it is in
> a superposition of states; that is, NOT in a definite state.
>

​The MWI can give a pretty good explanation why big things like the
Earth-Moon system and a small things like an electron behave so
differently, but to my mind Copenhagen is much less successful at doing
that.   ​

​> ​
> You're conflating Multiverse with the MWI.
>

​
You can't have the MWI without the Multiverse, and if there is a Multiverse
then the MWI explains a lot.
​ ​
There are about 10^80 atoms in the observable universe and obviously there
is a finite number of ways 10^80 atoms can be arranged in a sphere with a
radius of 13.8 billion light years; so if the
​entire ​
universe (not to be confused with the observable universe) is infinite then
at a very large but still finite distance things must repeat and there is a
universe identical to our own, and at another hyper large distance there is
a universe identical to ours except that the freckle on my right thumb is
on my left thumb instead. And at a even greater distance one second after a
John Clark hits send on a message identical to this one all the air
molecules in the room he is in go to the other side of the room due to
random thermal vibrations and that John Clark suffocates. Bizarre events
like that are not impossible just very very unlikely, but if the universe
is really infinite then everything that doesn't violate the laws of physics
will happen, and the Many World people say that's what the wave function is
trying to tell us, everything that can happen will happen.

​> ​
> where the energy comes from in the MWI cannot be easily dismissed by the
> lack of global energy conservation in GR,
>

​Why Not? Energy conservation is not a logical necessity, it was just a
empirical fact that we found that seemed to be always true, until it
wasn't. Twenty years ago we discovered the universe was accelerating.  ​

​> ​
> Agreed that "observation" is misleading when there is no consciousness
> involved in a quantum experiment. We should speak of detectable changes
> recorded by instruments; aka "measurements".
>

​Measurement is an even worse word to use than observation because it
implies not only information​

​but meaning, and you can's have meaning without a mind and you can't have
a mind without a brain and you can't have a brain without atoms arranged in
​certain patterns. Many Worlds strips things down to their bare essentials,
no need to worry about observation or measurement or information or meaning
or consciousness, all that's needed is a change.

​> ​
> So if David Deutsch takes a right turn at an intersection, there's another
> identical David Deutsch in another identical universe who takes a left
> turn? I can't disprove it, but why would anyone of sound mind want to
> assert it?
>

​Because  the bizarre outcome of experiments forces me to conclude the
universe is not of sound mind; if I were God I probably would have just
stuck with Newton but unfortunately I didn't get the job.  I admit the MWI
is stark raving mad, but the big question is it crazy enough to be true?
Whatever the truth turns out to be you can be certain it will seem nuts to
all bipedal hominids that evolved to be good at hunting game on the African
Savanna and not good at probing the mysteries of the quantum world. ​


​> ​
you can have a detector recording outcomes, and if the detector is designed
to determine which-way, the interference will be destroyed. In other words,
we can have quantum observations without any conscious "observer".

Yes, and that gives more support to many Worlds than Copenhagen. In the MWI
when the electron passes the slits the universe splits and if the which way
information is retained then there must be a physical difference between
the two universes because information is physical, and so they remain split
and no interference pattern is seen. However if after the split the which
way information is subsequently erased then there is no longer a physical

Re: Consistency of Postulates of QM

[Brent Meeker]

On 11/13/2017 1:40 PM, Bruce Kellett wrote:

On 14/11/2017 2:07 am, Bruno Marchal wrote:

On 12 Nov 2017, at 23:05, Bruce Kellett wrote:

What really annoys me is the continued claim that many worlds 
eliminates the need for non-locality. It does not, and neither Bruno 
nor anyone else has ever produced a valid argument as to how many 
worlds might restore locality.


But nobody has proved that there is non locality in the MWI. EPR-BELL 
proves non-locality apparant in each branch, but the MWI avoids the 
needs of action at a distance to explains them. Once Alice and Bob 
are space-separated, their identity are independent. It makes no 
sense to talk of each of them like if they were related, (unless you 
correlate them with a third observer, etc) If they do measurement, 
some God could see that they are indeed no more related, but if they 
decide to come back to place where they can compared locally their 
spin, they will always get contact to the corresponding observer with 
the well correlated spin. The independent Alice and Bob will never 
meet because they can't belong to the same branch of the multiverse, 
by the MWI of the singlet state. So Mitra is right. 
Although Bertlmann's socks are tyically not working for Bell's 
violation in a MONO-universe, it works again in the MWI, applied in 
this case to the whole singlet state.


Bell has proved non-locality in MWI, every bit as much as in each 
branch separately. You appear not to have grasped the significance of 
the scenario I have argued carefully. Alice and Bob are not space-like 
separated in the scenario I outlined. Alice and Bob are together in 
the same laboratory when the second measurement is made. They are 
necessarily in the same world before, and branch in together according 
to Bob's result. Your mumbo-jumbo about them only being able to meet 
in appropriate matching branches does not work here, because they are 
always in the same branch. And there is no reason to suppose that 
their results in some of those branches do not violate conservation of 
angular momentum.


It's that last point I don't understand.  Why isn't conservation of 
angular momentum a condition in every world.  It's something separate 
from QM.  I'd say there is non-locality even when Bob's measurement is 
time-like because there is correlation with no physical causal link.   
The "common cause" of conserved angular momentum is not an explanation 
because that doesn't work in the space-like case and there's no reason 
to suppose QM is different in the two cases.


Brent



Bruce
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Re: Consistency of Postulates of QM

[agrayson2000]

On Sunday, November 12, 2017 at 11:50:00 PM UTC-7, agrays...@gmail.com 
wrote:
>
>
>
> On Sunday, November 12, 2017 at 11:24:15 PM UTC-7, agrays...@gmail.com 
> wrote:
>>
>>
>>
>> On Sunday, November 12, 2017 at 11:15:33 AM UTC-7, John Clark wrote:
>>>
>>> On Sun, Nov 12, 2017 at 1:01 AM,  wrote:
>>>
>>> ​> ​
 What is your definition of non-realistic? 

>>>
>>> Nonrealistic means ​when something is not being observed it doesn't 
>>> exist in any one definite state.​
>>>  
>>> ​ 
>>>
>>
>> You have to be careful here. For example, when the Earth-Moon system 
>> formed, it existed in a definite state, but was NOT observed. So not 
>> everything in a definite state must be observed, by detectors or conscious 
>> entities. OTOH, when an electron is prepared for a double slit experiment, 
>> it is in a superposition of states; that is, NOT in a definite state. If it 
>> were in a definite state, we'd observe the classical probability 
>> distribution. So quantum experiments, and QM in general to the extent it 
>> relies on superposition of states, is NONREALISTIC, whereas the macro world 
>> is generally REALISTIC. I can't speak to why the macro world is 
>> realistic.
>>
>
> FWIW, I left out an important reason why some systems are in definite 
> states, like macro systems, and others not, such as quantum systems 
> prepared for measurements. It's likely related to whether the systems in 
> question are ISOLATED.
>

*If you find collapse of the wf anathema, instead of the MWI why not just 
assume the branches that aren't measured in this world, dissipate into the 
environment as I think Decoherence theory postulates?  MWI doesn't tell us 
what will be measured in this or any other particular world, so what's the 
downside to this hugely simpler way of avoiding collapse? *

>
> A photon ​hits a horizontally polarizing filter and the universe splits in 
>>> two if Many Worlds is right, in one the photon makes it through the filter 
>>> and the inhabitants of that world conclude it is 100% horizontally 
>>> polarized , in the other world it doesn't get through the filter and they 
>>> conclude it must have been 100% vertically polarized, but in the world 
>>> before the split, before it hit the filter, the inhabitants of that world 
>>> would conclude (if they believed in Many Worlds) that the photon did not 
>>> have any one definite polarized state at all. 
>>>
>>> ​
> ​>> ​
> That is not unique to the MWI. In a accelerating  ​Einsteinian 
> universe such as ours energy is not conserved at the cosmological level.
>

 ​> ​
 There was some unique condition that gave rise to our universe.

>>>
>>> ​The multiverse may have always existed, if so then nothing, unique or 
>>> otherwise, gave rise to it,​
>>>  
>>>
>>
>> You're conflating Multiverse with the MWI. In the former, OUR universe 
>> emerged due to unique, unknown initial conditions from an entity which, if 
>> it exists, is likely infinite in age and extent. In the MWI, universes 
>> allegedly emerge when Joe the Plumber shoots an electron at a slitted 
>> screen. The two situations are in no way comparable, and the latter seems 
>> hugely overblown IMO. So where the energy comes from in the MWI cannot be 
>> easily dismissed by the lack of global energy conservation in GR, or by 
>> referring to unknowns related to the emergence of our universe from a 
>> hypothetical Multiverse.
>>  
>>
>>>  
>>>
 ​> ​
 MWI has it happening wily-nily when someone performs a slit experiment 
 in a lab (and uncountably many times). Hardly a conservative 
 interpretation 
 IMO.  

>>>
>>> ​Many Worlds is very conservative if the mathematics doesn't say ​
>>> ​anything about a wave collapse. And it doesn't.
>>>
>>> ​>> ​
> they can't even say what is observation is. ​
>

 ​> ​
 I can. They can. In a SG experiment, e.g., an observation occurs when 
 the electron's spin state is aligned, or anti-aligned to the magnetic 
 field. 

>>>
>>> ​Observation is the wrong word if no observer is involved, then its 
>>> just a change and a change is the criteria Many Worlds uses. 
>>>
>>
>> Agreed that "observation" is misleading when there is no consciousness 
>> involved in a quantum experiment. We should speak of detectable changes 
>> recorded by instruments; aka "measurements".
>>  
>>
>>> In MWI everything that can happen does happen, so when a photon 
>>> approaches 2 slits the universe splits and one photon goes through the 
>>> right slit and one goes through the left slit. If after that the photons 
>>> hit a photographic plate (or a brick wall) then the photons no longer exist 
>>> in either universe and so they merge back together into one universe and 
>>> this merger causes the interference lines. If instead after passing the 
>>> slits there is no photographic plate (or brick wall) and the photons are 
>>> allowed to continue on into infinite space 

Re: Consistency of Postulates of QM

[Bruce Kellett]

On 14/11/2017 2:07 am, Bruno Marchal wrote:

On 12 Nov 2017, at 23:05, Bruce Kellett wrote:

What really annoys me is the continued claim that many worlds 
eliminates the need for non-locality. It does not, and neither Bruno 
nor anyone else has ever produced a valid argument as to how many 
worlds might restore locality.


But nobody has proved that there is non locality in the MWI. EPR-BELL 
proves non-locality apparant in each branch, but the MWI avoids the 
needs of action at a distance to explains them. Once Alice and Bob are 
space-separated, their identity are independent. It makes no sense to 
talk of each of them like if they were related, (unless you correlate 
them with a third observer, etc) If they do measurement, some God 
could see that they are indeed no more related, but if they decide to 
come back to place where they can compared locally their spin, they 
will always get contact to the corresponding observer with the well 
correlated spin. The independent Alice and Bob will never meet because 
they can't belong to the same branch of the multiverse, by the MWI of 
the singlet state. So Mitra is right. Although Bertlmann's socks are 
tyically not working for Bell's violation in a MONO-universe, it works 
again in the MWI, applied in this case to the whole singlet state.


Bell has proved non-locality in MWI, every bit as much as in each branch 
separately. You appear not to have grasped the significance of the 
scenario I have argued carefully. Alice and Bob are not space-like 
separated in the scenario I outlined. Alice and Bob are together in the 
same laboratory when the second measurement is made. They are 
necessarily in the same world before, and branch in together according 
to Bob's result. Your mumbo-jumbo about them only being able to meet in 
appropriate matching branches does not work here, because they are 
always in the same branch. And there is no reason to suppose that their 
results in some of those branches do not violate conservation of angular 
momentum.


Bruce

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Re: Consistency of Postulates of QM

[Bruno Marchal]

On 12 Nov 2017, at 23:05, Bruce Kellett wrote:


On 13/11/2017 4:02 am, Brent Meeker wrote:

On 11/11/2017 10:57 PM, Bruce Kellett wrote:

On 12/11/2017 5:39 pm, Brent Meeker wrote:

On 11/11/2017 9:56 PM, Bruce Kellett wrote:

On 12/11/2017 4:04 pm, Brent Meeker wrote:

On 11/11/2017 6:47 PM, Bruce Kellett wrote:

On 12/11/2017 4:34 am, John Clark wrote:
On Fri, Nov 10, 2017 at 7:08 PM, Alan Grayson  wrote:


​ ​ >> ​ That's not the measurement problem, its  
determining if how and why observation effects things. ​


​ > ​ Not to split hairs, but why we get what we get in  
quantum measurements, and how measurement outcomes come to be  
what they are, are the same problem IMO.


The measurement problem is not the ability or inability to  
predict exact outcomes, ​ ​ the measurement problem is  
defining what is ​ ​ and ​ ​ what ​ ​ is not a  
measurement and ​ ​ finding the ​ ​ minimum properties  
a system ​ ​ must ​ ​ have to be an observer.  
Nondeterminism is not a problem and there is no inconsistency  
at all regardless of what turns out to be true ​ ;​ if  
some effects have no cause and true randomness exists then  
that's just the way things are  
are ​ ​  and ​ ​t here is no  
resulting paradox and no question that needs answering.


​ The title of this thread is about the consistency of  
Quantum Mechanics, but far more important than QM is the  
ability of ANY theory to be compatible with experimental  
results, and one of those experiments shows the violation of  
Bell's Inequality. And that violation tells us that for ANY  
theory to be successful at explaining how the world works AT  
LEAST one of the following properties of that theory must be  
untrue:


1) Determinism
2) Locality
3) Realism

Is Many Worlds deterministic? Yes in the sense that it just  
follows the wave function and that is deterministic, it's  
only the collapse of the wave function that is  
nondeterministic and that never happens in Manny Worlds.


Is Many Worlds Local? Some say yes but I would say no because  
those other worlds are about as non-local as you can get, you  
can't get there even with infinite time on your side. But  
even if I'm wrong about locality Many Worlds would still be  
in the running for a successful theory because it is  
certainly not realistic.


I would agree with you that the many worlds account is non- 
local. The problem that MW faces is that the separate worlds  
split off when measurements are made at either end of the EPR  
experiment must somehow be made to match up appropriately when  
the two experimenters communicate. This requires coordination  
of separate worlds, which, as you say, is about as non-local  
as you can get.


The problem becomes particularly apparent if you consider an  
EPR experiment with time-like separation. Let Alice prepare an  
EPR pair in her laboratory, then measure the spin of one of  
the pair in some defined direction. She then takes the other  
member of the EPR pair down the corridor to her partner, Bob,  
and gets him to measure the spin projection in the same  
direction. If the two particles are independent, then both  
measurements give 50/50 chances for up/down. After Alice  
measures her particle, she splits into Alice_up and Alice  
_down according to her result. Both  copies  
then go to Bob's laboratory, which by then has also split  
according to Alice's result. So Alice_up meets Bob, but when  
he measures his particle, he still has 50/50 chances of either  
result. Unfortunately, the only result that is consistent with  
spin conservation is that if Alice got 'up', he must get  
'down', and vice verse (remember that the measurements are  
aligned by design).


Since Alice_up can't meet a Bob_up, there must be a non-local  
influence that determines Bob's result according to which  
Alice he meets. This is not removed be assuming no collapse  
and many worlds.


But Bruno's model assumes infinitely many worlds; some in which  
Alice sees up and Bob sees down and others in which Alice sees  
down and Bob sees up..."influence" doesn't really appear in the  
model because it's kind of block multiverse and there's some  
rule (conservation of angular momentum) that means up-up and  
down-down don't appear.  I think this is also true of t'Hooft's  
super-deterministic model because in that model there's nothing  
special about the event of Alice's measurement that needs to be  
communicated.  The idea of influence propagating from an event  
derives from the idea that Alice had "free-will" and so her  
choice had to be communicated from the measurement event.


That does not address the scenario I have outlined. In the time- 
like case, Alice_up meets Bob with a spin state that can result  
in either up or down; similarly Alice_down meets Bob with a spin  
state on which Bob's measurement can result in either up or down  
with 50% of each. There are only two worlds involved at 

Re: Consistency of Postulates of QM

[Bruno Marchal]

On 12 Nov 2017, at 23:23, Bruce Kellett wrote:


On 13/11/2017 4:13 am, Bruno Marchal wrote:

On 12 Nov 2017, at 03:47, Bruce Kellett wrote:

On 12/11/2017 4:34 am, John Clark wrote:
On Fri, Nov 10, 2017 at 7:08 PM, Alan Grayson  wrote:


​ ​ >> ​ That's not the measurement problem, its determining  
if how and why observation effects things. ​


​ > ​ Not to split hairs, but why we get what we get in  
quantum measurements, and how measurement outcomes come to be  
what they are, are the same problem IMO.


The measurement problem is not the ability or inability to  
predict exact outcomes, ​ ​ the measurement problem is  
defining what is ​ ​ and ​ ​ what ​ ​ is not a  
measurement and ​ ​ finding the ​ ​ minimum properties a  
system ​ ​ must ​ ​ have to be an observer. Nondeterminism  
is not a problem and there is no inconsistency at all regardless  
of what turns out to be true ​ ;​ if some effects have no  
cause and true randomness exists then that's just the way things  
are are ​ ​ and ​ ​t here is no resulting paradox and no  
question that needs answering.


​ The title of this thread is about the consistency of Quantum  
Mechanics, but far more important than QM is the ability of ANY  
theory to be compatible with experimental results, and one of  
those experiments shows the violation of Bell's Inequality. And  
that violation tells us that for ANY theory to be successful at  
explaining how the world works AT LEAST one of the following  
properties of that theory must be untrue:


1) Determinism
2) Locality
3) Realism

Is Many Worlds deterministic? Yes in the sense that it just  
follows the wave function and that is deterministic, it's only  
the collapse of the wave function that is nondeterministic and  
that never happens in Manny Worlds.


Is Many Worlds Local? Some say yes but I would say no because  
those other worlds are about as non-local as you can get, you  
can't get there even with infinite time on your side. But even if  
I'm wrong about locality Many Worlds would still be in the  
running for a successful theory because it is certainly not  
realistic.


I would agree with you that the many worlds account is non-local.  
The problem that MW faces is that the separate worlds split off  
when measurements are made at either end of the EPR experiment  
must somehow be made to match up appropriately when the two  
experimenters communicate. This requires coordination of separate  
worlds, which, as you say, is about as non-local as you can get.


OK, but without action at a distance. If you take into account the  
local propagation of the observers (treating them quantum  
mechanically), and the same for their "future" counterparts. The  
coordination is just kept locally by the observers. There is a  
strong "local" first person sharable non locality, but yet no  
physical action at a distance, nor problem with physical realism  
(albeit multiversal).


Non-locality just means that there is a non-local influence -- what  
happens to one member of an entangled pair influences the behaviour  
of the other. No model is proposed for how this happens, because any  
local causal model would have to be of the 'hidden variable' type,  
and Bell has ruled out such local hidden variable accounts. The  
'Quantum Mechanics is incomplete' route is ruled out. Maudlin  
explores this in considerable detail in his book.


The problem becomes particularly apparent if you consider an EPR  
experiment with time-like separation. Let Alice prepare an EPR  
pair in her laboratory, then measure the spin of one of the pair  
in some defined direction. She then takes the other member of the  
EPR pair down the corridor to her partner, Bob, and gets him to  
measure the spin projection in the same direction. If the two  
particles are independent,

then both measurements give 50/50 chances for up/down.


OK. But they are not independent. After her measurement she is in a  
class of worlds with some definite result for both particle, with  
respect to the base up/down.


There is no 'class of worlds'. There are two worlds, one  
corresponding to each of the possible results for Alice's measurement.



After Alice measures her particle, she splits into Alice_up and  
Alice _down according to her result. Both copies then go to Bob's  
laboratory, which by then has also split according to Alice's  
result.


OK.



So Alice_up meets Bob, but when he measures his particle, he still  
has 50/50 chances of either result.


I don't think so. Only if he got the time to do it before Alice  
splits has not rich him.


Locality says unequivocally that what I say is correct: the particle  
that Alice presents to Bob (in each world) is in exactly the same  
spin state as when produced.


But he would propagate a possibly "violating Bell" result to a  
different Alice, just by tyhe lienarity of the tensor products and  
evolution.


I don't understand this comment. Alice and Bob have 

Re: Consistency of Postulates of QM

[Bruno Marchal]

On 12 Nov 2017, at 22:40, Bruce Kellett wrote:


On 13/11/2017 5:15 am, Bruno Marchal wrote:

On 12 Nov 2017, at 07:57, Bruce Kellett wrote:

If that means anything at all, it is still non-local because Bruno  
has to rule out the worlds in which angular momentum is not  
conserved;  he has not shown how he can do this. If it is simply  
that you cannot find yourself in a world in which AM is not  
conserved, then that is just an unabashed appeal to magic, since  
such worlds have not been shown not to exist.



I just assume quantum mechanics without collapse here.

When I assume Mechanism, we are in a different field, and there at  
first sight we get total indeterminacy, super-non locality, etc.,  
and the hard things is to explain the local appearance of  
determinism, locality, etc. With mechanism we have the quantum  
logic, the symmetries, but the Bell's theorem is already  
untractable. The interest reside in getting a unify picture of  
qualia and quanta, albeit in a platonic metaphysics, excluding the  
usual Aristotelian one.


In other words, you have no idea how to explain the violations of  
Bell's inequality -- in many worlds or any other account of QM.


In mechanism, the status is decided, but still untractable.




It is a pity you continue to claim that many worlds eliminates the  
need for non-locality.


Sorry but you continue to mix two different theories.


And quantum mechanics is a deterministic local theory. The non  
locality and the indeterminacies are explained to be apparent in each  
branche, but without any action at a distance, as you can see when you  
develop the experiment in all branches (that is with theuniversal   
wave).


We have discussed this, and it seemed to me you were OK with the fact  
that QM does not imply physical action at a distance (even withot  
transmission of information),. All I said is that QM does not imply  
that. And it is open problem if Digital Mechanism is true.


Bruno




Bruce

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Re: Consistency of Postulates of QM

[agrayson2000]

On Sunday, November 12, 2017 at 11:24:15 PM UTC-7, agrays...@gmail.com 
wrote:
>
>
>
> On Sunday, November 12, 2017 at 11:15:33 AM UTC-7, John Clark wrote:
>>
>> On Sun, Nov 12, 2017 at 1:01 AM,  wrote:
>>
>> ​> ​
>>> What is your definition of non-realistic? 
>>>
>>
>> Nonrealistic means ​when something is not being observed it doesn't exist 
>> in any one definite state.​
>>  
>> ​ 
>>
>
> You have to be careful here. For example, when the Earth-Moon system 
> formed, it existed in a definite state, but was NOT observed. So not 
> everything in a definite state must be observed, by detectors or conscious 
> entities. OTOH, when an electron is prepared for a double slit experiment, 
> it is in a superposition of states; that is, NOT in a definite state. If it 
> were in a definite state, we'd observe the classical probability 
> distribution. So quantum experiments, and QM in general to the extent it 
> relies on superposition of states, is NONREALISTIC, whereas the macro world 
> is generally REALISTIC. I can't speak to why the macro world is realistic.
>

FWIW, I left out an important reason why some systems are in definite 
states, like macro systems, and others not, such as quantum systems 
prepared for measurements. It's likely related to whether the systems in 
question are ISOLATED.

A photon ​hits a horizontally polarizing filter and the universe splits in 
>> two if Many Worlds is right, in one the photon makes it through the filter 
>> and the inhabitants of that world conclude it is 100% horizontally 
>> polarized , in the other world it doesn't get through the filter and they 
>> conclude it must have been 100% vertically polarized, but in the world 
>> before the split, before it hit the filter, the inhabitants of that world 
>> would conclude (if they believed in Many Worlds) that the photon did not 
>> have any one definite polarized state at all. 
>>
>> ​
 ​>> ​
 That is not unique to the MWI. In a accelerating  ​Einsteinian universe 
 such as ours energy is not conserved at the cosmological level.

>>>
>>> ​> ​
>>> There was some unique condition that gave rise to our universe.
>>>
>>
>> ​The multiverse may have always existed, if so then nothing, unique or 
>> otherwise, gave rise to it,​
>>  
>>
>
> You're conflating Multiverse with the MWI. In the former, OUR universe 
> emerged due to unique, unknown initial conditions from an entity which, if 
> it exists, is likely infinite in age and extent. In the MWI, universes 
> allegedly emerge when Joe the Plumber shoots an electron at a slitted 
> screen. The two situations are in no way comparable, and the latter seems 
> hugely overblown IMO. So where the energy comes from in the MWI cannot be 
> easily dismissed by the lack of global energy conservation in GR, or by 
> referring to unknowns related to the emergence of our universe from a 
> hypothetical Multiverse.
>  
>
>>  
>>
>>> ​> ​
>>> MWI has it happening wily-nily when someone performs a slit experiment 
>>> in a lab (and uncountably many times). Hardly a conservative interpretation 
>>> IMO.  
>>>
>>
>> ​Many Worlds is very conservative if the mathematics doesn't say ​
>> ​anything about a wave collapse. And it doesn't.
>>
>> ​>> ​
 they can't even say what is observation is. ​

>>>
>>> ​> ​
>>> I can. They can. In a SG experiment, e.g., an observation occurs when 
>>> the electron's spin state is aligned, or anti-aligned to the magnetic 
>>> field. 
>>>
>>
>> ​Observation is the wrong word if no observer is involved, then its just 
>> a change and a change is the criteria Many Worlds uses. 
>>
>
> Agreed that "observation" is misleading when there is no consciousness 
> involved in a quantum experiment. We should speak of detectable changes 
> recorded by instruments; aka "measurements".
>  
>
>> In MWI everything that can happen does happen, so when a photon 
>> approaches 2 slits the universe splits and one photon goes through the 
>> right slit and one goes through the left slit. If after that the photons 
>> hit a photographic plate (or a brick wall) then the photons no longer exist 
>> in either universe and so they merge back together into one universe and 
>> this merger causes the interference lines. If instead after passing the 
>> slits there is no photographic plate (or brick wall) and the photons are 
>> allowed to continue on into infinite space then the 2 universes remain 
>> different and remain separated forever.
>>
>
> So if David Deutsch takes a right turn at an intersection, there's another 
> identical David Deutsch in another identical universe who takes a left 
> turn? I can't disprove it, but why would anyone of sound mind want to 
> assert it? 
>
>>
>> The universe splits because there is a difference, in one the photon went 
>> through the left slit and in another it went through the right slit, and 
>> the wave function never collapses it just keeps on going. And there is 
>> nothing special about me, 

Re: Consistency of Postulates of QM

[agrayson2000]

On Sunday, November 12, 2017 at 11:15:33 AM UTC-7, John Clark wrote:
>
> On Sun, Nov 12, 2017 at 1:01 AM,  
> wrote:
>
> ​> ​
>> What is your definition of non-realistic? 
>>
>
> Nonrealistic means ​when something is not being observed it doesn't exist 
> in any one definite state.​
>  
> ​ 
>

You have to be careful here. For example, when the Earth-Moon system 
formed, it existed in a definite state, but was NOT observed. So not 
everything in a definite state must be observed, by detectors or conscious 
entities. OTOH, when an electron is prepared for a double slit experiment, 
it is in a superposition of states; that is, NOT in a definite state. If it 
were in a definite state, we'd observe the classical probability 
distribution. So quantum experiments, and QM in general to the extent it 
relies on superposition of states, is NONREALISTIC, whereas the macro world 
is generally REALISTIC. I can't speak to why the macro world is realistic.
 

> A photon ​hits a horizontally polarizing filter and the universe splits in 
> two if Many Worlds is right, in one the photon makes it through the filter 
> and the inhabitants of that world conclude it is 100% horizontally 
> polarized , in the other world it doesn't get through the filter and they 
> conclude it must have been 100% vertically polarized, but in the world 
> before the split, before it hit the filter, the inhabitants of that world 
> would conclude (if they believed in Many Worlds) that the photon did not 
> have any one definite polarized state at all. 
>
> ​
>>> ​>> ​
>>> That is not unique to the MWI. In a accelerating  ​Einsteinian universe 
>>> such as ours energy is not conserved at the cosmological level.
>>>
>>
>> ​> ​
>> There was some unique condition that gave rise to our universe.
>>
>
> ​The multiverse may have always existed, if so then nothing, unique or 
> otherwise, gave rise to it,​
>  
>

You're conflating Multiverse with the MWI. In the former, OUR universe 
emerged due to unique, unknown initial conditions from an entity which, if 
it exists, is likely infinite in age and extent. In the MWI, universes 
allegedly emerge when Joe the Plumber shoots an electron at a slitted 
screen. The two situations are in no way comparable, and the latter seems 
hugely overblown IMO. So where the energy comes from in the MWI cannot be 
easily dismissed by the lack of global energy conservation in GR, or by 
referring to unknowns related to the emergence of our universe from a 
hypothetical Multiverse.
 

>  
>
>> ​> ​
>> MWI has it happening wily-nily when someone performs a slit experiment in 
>> a lab (and uncountably many times). Hardly a conservative interpretation 
>> IMO.  
>>
>
> ​Many Worlds is very conservative if the mathematics doesn't say ​
> ​anything about a wave collapse. And it doesn't.
>
> ​>> ​
>>> they can't even say what is observation is. ​
>>>
>>
>> ​> ​
>> I can. They can. In a SG experiment, e.g., an observation occurs when the 
>> electron's spin state is aligned, or anti-aligned to the magnetic field. 
>>
>
> ​Observation is the wrong word if no observer is involved, then its just 
> a change and a change is the criteria Many Worlds uses. 
>

Agreed that "observation" is misleading when there is no consciousness 
involved in a quantum experiment. We should speak of detectable changes 
recorded by instruments; aka "measurements".
 

> In MWI everything that can happen does happen, so when a photon 
> approaches 2 slits the universe splits and one photon goes through the 
> right slit and one goes through the left slit. If after that the photons 
> hit a photographic plate (or a brick wall) then the photons no longer exist 
> in either universe and so they merge back together into one universe and 
> this merger causes the interference lines. If instead after passing the 
> slits there is no photographic plate (or brick wall) and the photons are 
> allowed to continue on into infinite space then the 2 universes remain 
> different and remain separated forever.
>

So if David Deutsch takes a right turn at an intersection, there's another 
identical David Deutsch in another identical universe who takes a left 
turn? I can't disprove it, but why would anyone of sound mind want to 
assert it? 

>
> The universe splits because there is a difference, in one the photon went 
> through the left slit and in another it went through the right slit, and 
> the wave function never collapses it just keeps on going. And there is 
> nothing special about me, I split just like everything else in the 
> universe, the fact that I am conscious is irrelevant.  That's another great 
> advantage of Many Worlds, unlike Copenhagen it doesn't need to explain what 
> consciousness is or how it works because consciousness has nothing to do 
> with it.   
>

As I previously pointed out, the alleged collapse of the wf has nothing to 
do with consciousness regardless of what Bohr or others might have 
speculated in the 

Re: Consistency of Postulates of QM

[Bruce Kellett]

On 13/11/2017 12:15 pm, smitra wrote:

On 12-11-2017 22:54, Bruce Kellett wrote:

On 13/11/2017 7:19 am, smitra wrote:

On 12-11-2017 11:21, Bruce Kellett wrote:

On 12/11/2017 9:14 pm, smitra wrote:

On 12-11-2017 07:57, Bruce Kellett wrote:

On 12/11/2017 5:39 pm, Brent Meeker wrote:


In Bruno's model the "influence at a distance" is determing which
world you're in.


 If that means anything at all, it is still non-local because Bruno
has to rule out the worlds in which angular momentum is not 
conserved;
 he has not shown how he can do this. If it is simply that you 
cannot

find yourself in a world in which AM is not conserved, then that is
just an unabashed appeal to magic, since such worlds have not been
shown not to exist.

 Bruce


There are two correlated copies of Alice and Bob induced by the 
correlated spins, there is nothing nonlocal about that in the MWI. 
There is only a non- locality problem here if you assume a 
collapse interpretation of QM. In the MWI the correlation arises 
via an originally local common cause.


There is no collapse assumption in anything that I have written about
this scenario. What is the local common cause in MWI? Is that a local
hidden variable? Such would work in the time-like case, but not in
general -- that is Bell's result.

But you have still not answered the fundamental question as to what
causes Bob to necessarily measure spin down when Alice joins him with
a spin-up result? What turns Bob's particle from an unpolarized to a
polarized state so that the probabilities change from 50/50 to 100%
for spin down?

Bruce


Bob's particle never changed due to anything Alice did in the MWI.


Right.

All that happened was that Alice got entangled with her particle 
(and not just Alice,  her entire environment gets entangled with the 
state of her particle), which in turn was entangled with Bob's 
particle. So, Bob has the same probabilities for finding spin up or 
down,


Right. In fact, when Alice_up meets Bob, and Alice_down meets Bob in
the parallel universe, they can both tell Bob their result, and the
direction in which they measured the spin. This makes no difference,
since Bob is now entangled with the Alice's that have definite
results. None of this makes any difference to the particle Bob
measures, because, by the definition of locality, nothing has
interacted with Bob's particle, so it must be in the same spin state
as when it was produced.


except that he can now measure the state of his particle by 
performing a measurement on Alice,  by asking her what she found for 
her spin.


That is not a measurement, that is making a prediction based on the
conservation of angular momentum.

It's not true that before Bob knows what Alice has found that only 
one of the two version's of Alice has arrived and that the 
information of her spin state is then already present in Bob's 
sector. This is not true in the MWI, decoherence simple means that 
you can't demonstrate the existence of the two versions of Alice via 
an interference experiment. But the inability to do so, doesn't by 
itself imply that only one version really exists.


I don't think you have fully understood the scenario I have outlined.
There is no collapse, many worlds is assumed throughout. Alice splits
according to her measurement result. Both copies of Alice go to meet
Bob, carrying the other particle of the original pair. Since they both
have now met Bob, the split that Alice occasioned has now spread to
entangle Bob as well as the rest of her environment. So there are now
two worlds, each of which has a copy of Bob, and an Alice, who has a
particular result. Locality says that Bob's particle is unchanged from
production, so when he measure its spin, he splits into two copies,
according to spin up or spin down. Since Alice is standing beside him,
she also becomes entangled with his result. But Alice already has a
definite result in each branch, so we now have four branches: with
results 'up-up', 'up-down', 'down-up', and 'down-down'. However, only
the 'up-down' and 'down-up' branches conserve angular momentum. How do
you rule out the other branches?

Bruce


The splitting as an apparent nonlocal aspect to it, which is  due to a 
common cause effect, the spins were entangled, and that entanglement 
happened when the spins were created due to a local interaction in the 
past.


Yes, the entangled spin zero state was created in the past.

If you then let Alice and Bob measure the space-like separated spins, 
they'll split up, and that happens in a correlated way, because the 
spins are correlated. It is just the MWI variant of Bertlmann's socks


That is not correct. The correlation you seems to be relying on is 
non-local once the particles have separated. As Bell pointed out, 
Bertlmann's socks are the wrong way to look at it! Besides, my variation 
was to look at time-like separated measurements so that one could keep 
explicit track of the splitting into separate worlds -- Bob and Alice, 
in 

Re: Consistency of Postulates of QM

[smitra]

On 12-11-2017 22:54, Bruce Kellett wrote:

On 13/11/2017 7:19 am, smitra wrote:

On 12-11-2017 11:21, Bruce Kellett wrote:

On 12/11/2017 9:14 pm, smitra wrote:

On 12-11-2017 07:57, Bruce Kellett wrote:

On 12/11/2017 5:39 pm, Brent Meeker wrote:


In Bruno's model the "influence at a distance" is determing which
world you're in.


 If that means anything at all, it is still non-local because Bruno
has to rule out the worlds in which angular momentum is not 
conserved;
 he has not shown how he can do this. If it is simply that you 
cannot

find yourself in a world in which AM is not conserved, then that is
just an unabashed appeal to magic, since such worlds have not been
shown not to exist.

 Bruce


There are two correlated copies of Alice and Bob induced by the 
correlated spins, there is nothing nonlocal about that in the MWI. 
There is only a non- locality problem here if you assume a collapse 
interpretation of QM. In the MWI the correlation arises via an 
originally local common cause.


There is no collapse assumption in anything that I have written about
this scenario. What is the local common cause in MWI? Is that a local
hidden variable? Such would work in the time-like case, but not in
general -- that is Bell's result.

But you have still not answered the fundamental question as to what
causes Bob to necessarily measure spin down when Alice joins him with
a spin-up result? What turns Bob's particle from an unpolarized to a
polarized state so that the probabilities change from 50/50 to 100%
for spin down?

Bruce


Bob's particle never changed due to anything Alice did in the MWI.


Right.

All that happened was that Alice got entangled with her particle (and 
not just Alice,  her entire environment gets entangled with the state 
of her particle), which in turn was entangled with Bob's particle. So, 
Bob has the same probabilities for finding spin up or down,


Right. In fact, when Alice_up meets Bob, and Alice_down meets Bob in
the parallel universe, they can both tell Bob their result, and the
direction in which they measured the spin. This makes no difference,
since Bob is now entangled with the Alice's that have definite
results. None of this makes any difference to the particle Bob
measures, because, by the definition of locality, nothing has
interacted with Bob's particle, so it must be in the same spin state
as when it was produced.


except that he can now measure the state of his particle by performing 
a measurement on Alice,  by asking her what she found for her spin.


That is not a measurement, that is making a prediction based on the
conservation of angular momentum.

It's not true that before Bob knows what Alice has found that only one 
of the two version's of Alice has arrived and that the information of 
her spin state is then already present in Bob's sector. This is not 
true in the MWI, decoherence simple means that you can't demonstrate 
the existence of the two versions of Alice via an interference 
experiment. But the inability to do so, doesn't by itself imply that 
only one version really exists.


I don't think you have fully understood the scenario I have outlined.
There is no collapse, many worlds is assumed throughout. Alice splits
according to her measurement result. Both copies of Alice go to meet
Bob, carrying the other particle of the original pair. Since they both
have now met Bob, the split that Alice occasioned has now spread to
entangle Bob as well as the rest of her environment. So there are now
two worlds, each of which has a copy of Bob, and an Alice, who has a
particular result. Locality says that Bob's particle is unchanged from
production, so when he measure its spin, he splits into two copies,
according to spin up or spin down. Since Alice is standing beside him,
she also becomes entangled with his result. But Alice already has a
definite result in each branch, so we now have four branches: with
results 'up-up', 'up-down', 'down-up', and 'down-down'. However, only
the 'up-down' and 'down-up' branches conserve angular momentum. How do
you rule out the other branches?

Bruce


The splitting as an apparent nonlocal aspect to it, which is  due to a 
common cause effect, the spins were entangled, and that entanglement 
happened when the spins were created due to a local interaction in the 
past.


If you then let Alice and Bob measure the space-like separated spins, 
they'll split up, and that happens in a correlated way, because the 
spins are correlated. It is just the MWI variant of Bertlmann's socks


Saibal

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Re: Consistency of Postulates of QM

[Bruce Kellett]

On 13/11/2017 4:13 am, Bruno Marchal wrote:

On 12 Nov 2017, at 03:47, Bruce Kellett wrote:

On 12/11/2017 4:34 am, John Clark wrote:
On Fri, Nov 10, 2017 at 7:08 PM, Alan Grayson 
wrote:


​
​ >> ​
That's not the measurement problem, its determining if how
and why observation effects things. ​


​ > ​
Not to split hairs, but why we get what we get in quantum
measurements, and how measurement outcomes come to be what they
are, are the same problem IMO.


The measurement problem is not the ability or inability to predict 
exact outcomes,

​ ​
the measurement problem is defining what is
​ ​
and
​ ​
what
​ ​
is not a measurement and
​ ​
finding the
​ ​
minimum properties a system
​ ​
must
​ ​
have to be an observer. Nondeterminism is not a problem and there is 
no inconsistency at all regardless of what turns out to be true

​ ;​
if some effects have no cause and true randomness exists then that's 
just the way things are are

​ ​
and
​ ​t
here is no resulting paradox and no question that needs answering.

​
The title of this thread is about the consistency of Quantum 
Mechanics, but far more important than QM is the ability of ANY 
theory to be compatible with experimental results, and one of those 
experiments shows the violation of Bell's Inequality. And that 
violation tells us that for ANY theory to be successful at 
explaining how the world works AT LEAST one of the following 
properties of that theory must be untrue:


1) Determinism
2) Locality
3) Realism

Is Many Worlds deterministic? Yes in the sense that it just follows 
the wave function and that is deterministic, it's only the collapse 
of the wave function that is nondeterministic and that never happens 
in Manny Worlds.


Is Many Worlds Local? Some say yes but I would say no because those 
other worlds are about as non-local as you can get, you can't get 
there even with infinite time on your side. But even if I'm wrong 
about locality Many Worlds would still be in the running for a 
successful theory because it is certainly not realistic.


I would agree with you that the many worlds account is non-local. The 
problem that MW faces is that the separate worlds split off when 
measurements are made at either end of the EPR experiment must 
somehow be made to match up appropriately when the two experimenters 
communicate. This requires coordination of separate worlds, which, as 
you say, is about as non-local as you can get.


OK, but without action at a distance. If you take into account the 
local propagation of the observers (treating them quantum 
mechanically), and the same for their "future" counterparts. The 
coordination is just kept locally by the observers. There is a strong 
"local" first person sharable non locality, but yet no physical action 
at a distance, nor problem with physical realism (albeit multiversal).


Non-locality just means that there is a non-local influence -- what 
happens to one member of an entangled pair influences the behaviour of 
the other. No model is proposed for how this happens, because any local 
causal model would have to be of the 'hidden variable' type, and Bell 
has ruled out such local hidden variable accounts. The 'Quantum 
Mechanics is incomplete' route is ruled out. Maudlin explores this in 
considerable detail in his book.


The problem becomes particularly apparent if you consider an EPR 
experiment with time-like separation. Let Alice prepare an EPR pair 
in her laboratory, then measure the spin of one of the pair in some 
defined direction. She then takes the other member of the EPR pair 
down the corridor to her partner, Bob, and gets him to measure the 
spin projection in the same direction. If the two particles are 
independent,

then both measurements give 50/50 chances for up/down.


OK. But they are not independent. After her measurement she is in a 
class of worlds with some definite result for both particle, with 
respect to the base up/down.


There is no 'class of worlds'. There are two worlds, one corresponding 
to each of the possible results for Alice's measurement.



After Alice measures her particle, she splits into Alice_up and Alice 
_down according to her result. Both copies then go to Bob's 
laboratory, which by then has also split according to Alice's result.


OK.



So Alice_up meets Bob, but when he measures his particle, he still 
has 50/50 chances of either result.


I don't think so. Only if he got the time to do it before Alice splits 
has not rich him.


Locality says unequivocally that what I say is correct: the particle 
that Alice presents to Bob (in each world) is in exactly the same spin 
state as when produced.


But he would propagate a possibly "violating Bell" result to a 
different Alice, just by tyhe lienarity of the tensor products and 
evolution.


I don't understand this comment. Alice and Bob have communicated, she 
has told him her measurement angle and the result she 

Re: Consistency of Postulates of QM

[Bruce Kellett]

On 13/11/2017 4:02 am, Brent Meeker wrote:

On 11/11/2017 10:57 PM, Bruce Kellett wrote:

On 12/11/2017 5:39 pm, Brent Meeker wrote:

On 11/11/2017 9:56 PM, Bruce Kellett wrote:

On 12/11/2017 4:04 pm, Brent Meeker wrote:

On 11/11/2017 6:47 PM, Bruce Kellett wrote:

On 12/11/2017 4:34 am, John Clark wrote:
On Fri, Nov 10, 2017 at 7:08 PM, Alan Grayson 
wrote:


​
​ >> ​
That's not the measurement problem, its determining if
how and why observation effects things. ​


​ > ​
Not to split hairs, but why we get what we get in quantum
measurements, and how measurement outcomes come to be what
they are, are the same problem IMO.


The measurement problem is not the ability or inability to 
predict exact outcomes,

​ ​
the measurement problem is defining what is
​ ​
and
​ ​
what
​ ​
is not a measurement and
​ ​
finding the
​ ​
minimum properties a system
​ ​
must
​ ​
have to be an observer. Nondeterminism is not a problem and 
there is no inconsistency at all regardless of what turns out to 
be true

​ ;​
if some effects have no cause and true randomness exists then 
that's just the way things are are

​ ​
and
​ ​t
here is no resulting paradox and no question that needs answering.

​
The title of this thread is about the consistency of Quantum 
Mechanics, but far more important than QM is the ability of ANY 
theory to be compatible with experimental results, and one of 
those experiments shows the violation of Bell's Inequality. And 
that violation tells us that for ANY theory to be successful at 
explaining how the world works AT LEAST one of the following 
properties of that theory must be untrue:


1) Determinism
2) Locality
3) Realism

Is Many Worlds deterministic? Yes in the sense that it just 
follows the wave function and that is deterministic, it's only 
the collapse of the wave function that is nondeterministic and 
that never happens in Manny Worlds.


Is Many Worlds Local? Some say yes but I would say no 
because those other worlds are about as non-local as you can 
get, you can't get there even with infinite time on your side. 
But even if I'm wrong about locality Many Worlds would still be 
in the running for a successful theory because it is certainly 
not realistic.


I would agree with you that the many worlds account is non-local. 
The problem that MW faces is that the separate worlds split off 
when measurements are made at either end of the EPR experiment 
must somehow be made to match up appropriately when the two 
experimenters communicate. This requires coordination of separate 
worlds, which, as you say, is about as non-local as you can get.


The problem becomes particularly apparent if you consider an EPR 
experiment with time-like separation. Let Alice prepare an EPR 
pair in her laboratory, then measure the spin of one of the pair 
in some defined direction. She then takes the other member of the 
EPR pair down the corridor to her partner, Bob, and gets him to 
measure the spin projection in the same direction. If the two 
particles are independent, then both measurements give 50/50 
chances for up/down. After Alice measures her particle, she 
splits into Alice_up and Alice _down according to her result. 
Both copies then go to Bob's laboratory, which by then has also 
split according to Alice's result. So Alice_up meets Bob, but 
when he measures his particle, he still has 50/50 chances of 
either result. Unfortunately, the only result that is consistent 
with spin conservation is that if Alice got 'up', he must get 
'down', and vice verse (remember that the measurements are 
aligned by design).


Since Alice_up can't meet a Bob_up, there must be a non-local 
influence that determines Bob's result according to which Alice 
he meets. This is not removed be assuming no collapse and many 
worlds.


But Bruno's model assumes infinitely many worlds; some in which 
Alice sees up and Bob sees down and others in which Alice sees 
down and Bob sees up..."influence" doesn't really appear in the 
model because it's kind of block multiverse and there's some rule 
(conservation of angular momentum) that means up-up and down-down 
don't appear.  I think this is also true of t'Hooft's 
super-deterministic model because in that model there's nothing 
special about the event of Alice's measurement that needs to be 
communicated.  The idea of influence propagating from an event 
derives from the idea that Alice had "free-will" and so her choice 
had to be communicated from the measurement event.


That does not address the scenario I have outlined. In the 
time-like case, Alice_up meets Bob with a spin state that can 
result in either up or down; similarly Alice_down meets Bob with a 
spin state on which Bob's measurement can result in either up or 
down with 50% of each. There are only two worlds involved at that 
stage. 


No, that's the point.  There are infinitely many "worlds" involved 
from the beginning.  There's no 

Re: Consistency of Postulates of QM

[Bruce Kellett]

On 13/11/2017 7:19 am, smitra wrote:

On 12-11-2017 11:21, Bruce Kellett wrote:

On 12/11/2017 9:14 pm, smitra wrote:

On 12-11-2017 07:57, Bruce Kellett wrote:

On 12/11/2017 5:39 pm, Brent Meeker wrote:


In Bruno's model the "influence at a distance" is determing which
world you're in.


 If that means anything at all, it is still non-local because Bruno
has to rule out the worlds in which angular momentum is not conserved;
 he has not shown how he can do this. If it is simply that you cannot
find yourself in a world in which AM is not conserved, then that is
just an unabashed appeal to magic, since such worlds have not been
shown not to exist.

 Bruce


There are two correlated copies of Alice and Bob induced by the 
correlated spins, there is nothing nonlocal about that in the MWI. 
There is only a non- locality problem here if you assume a collapse 
interpretation of QM. In the MWI the correlation arises via an 
originally local common cause.


There is no collapse assumption in anything that I have written about
this scenario. What is the local common cause in MWI? Is that a local
hidden variable? Such would work in the time-like case, but not in
general -- that is Bell's result.

But you have still not answered the fundamental question as to what
causes Bob to necessarily measure spin down when Alice joins him with
a spin-up result? What turns Bob's particle from an unpolarized to a
polarized state so that the probabilities change from 50/50 to 100%
for spin down?

Bruce


Bob's particle never changed due to anything Alice did in the MWI.


Right.

All that happened was that Alice got entangled with her particle (and 
not just Alice,  her entire environment gets entangled with the state 
of her particle), which in turn was entangled with Bob's particle. So, 
Bob has the same probabilities for finding spin up or down,


Right. In fact, when Alice_up meets Bob, and Alice_down meets Bob in the 
parallel universe, they can both tell Bob their result, and the 
direction in which they measured the spin. This makes no difference, 
since Bob is now entangled with the Alice's that have definite results. 
None of this makes any difference to the particle Bob measures, because, 
by the definition of locality, nothing has interacted with Bob's 
particle, so it must be in the same spin state as when it was produced.



except that he can now measure the state of his particle by performing 
a measurement on Alice,  by asking her what she found for her spin.


That is not a measurement, that is making a prediction based on the 
conservation of angular momentum.


It's not true that before Bob knows what Alice has found that only one 
of the two version's of Alice has arrived and that the information of 
her spin state is then already present in Bob's sector. This is not 
true in the MWI, decoherence simple means that you can't demonstrate 
the existence of the two versions of Alice via an interference 
experiment. But the inability to do so, doesn't by itself imply that 
only one version really exists.


I don't think you have fully understood the scenario I have outlined. 
There is no collapse, many worlds is assumed throughout. Alice splits 
according to her measurement result. Both copies of Alice go to meet 
Bob, carrying the other particle of the original pair. Since they both 
have now met Bob, the split that Alice occasioned has now spread to 
entangle Bob as well as the rest of her environment. So there are now 
two worlds, each of which has a copy of Bob, and an Alice, who has a 
particular result. Locality says that Bob's particle is unchanged from 
production, so when he measure its spin, he splits into two copies, 
according to spin up or spin down. Since Alice is standing beside him, 
she also becomes entangled with his result. But Alice already has a 
definite result in each branch, so we now have four branches: with 
results 'up-up', 'up-down', 'down-up', and 'down-down'. However, only 
the 'up-down' and 'down-up' branches conserve angular momentum. How do 
you rule out the other branches?


Bruce

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Re: Consistency of Postulates of QM

[Bruce Kellett]

On 13/11/2017 5:15 am, Bruno Marchal wrote:

On 12 Nov 2017, at 07:57, Bruce Kellett wrote:

If that means anything at all, it is still non-local because Bruno 
has to rule out the worlds in which angular momentum is not 
conserved;  he has not shown how he can do this. If it is simply that 
you cannot find yourself in a world in which AM is not conserved, 
then that is just an unabashed appeal to magic, since such worlds 
have not been shown not to exist.



I just assume quantum mechanics without collapse here.

When I assume Mechanism, we are in a different field, and there at 
first sight we get total indeterminacy, super-non locality, etc., and 
the hard things is to explain the local appearance of determinism, 
locality, etc. With mechanism we have the quantum logic, the 
symmetries, but the Bell's theorem is already untractable. The 
interest reside in getting a unify picture of qualia and quanta, 
albeit in a platonic metaphysics, excluding the usual Aristotelian one.


In other words, you have no idea how to explain the violations of Bell's 
inequality -- in many worlds or any other account of QM. It is a pity 
you continue to claim that many worlds eliminates the need for non-locality.


Bruce

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Re: Consistency of Postulates of QM

[smitra]

On 12-11-2017 11:21, Bruce Kellett wrote:

On 12/11/2017 9:14 pm, smitra wrote:

On 12-11-2017 07:57, Bruce Kellett wrote:

On 12/11/2017 5:39 pm, Brent Meeker wrote:


In Bruno's model the "influence at a distance" is determing which
world you're in.


 If that means anything at all, it is still non-local because Bruno
has to rule out the worlds in which angular momentum is not 
conserved;

 he has not shown how he can do this. If it is simply that you cannot
find yourself in a world in which AM is not conserved, then that is
just an unabashed appeal to magic, since such worlds have not been
shown not to exist.

 Bruce


There are two correlated copies of Alice and Bob induced by the 
correlated spins, there is nothing nonlocal about that in the MWI. 
There is only a non- locality problem here if you assume a collapse 
interpretation of QM. In the MWI the correlation arises via an 
originally local common cause.


There is no collapse assumption in anything that I have written about
this scenario. What is the local common cause in MWI? Is that a local
hidden variable? Such would work in the time-like case, but not in
general -- that is Bell's result.

But you have still not answered the fundamental question as to what
causes Bob to necessarily measure spin down when Alice joins him with
a spin-up result? What turns Bob's particle from an unpolarized to a
polarized state so that the probabilities change from 50/50 to 100%
for spin down?

Bruce


Bob's particle never changed due to anything Alice did in the MWI. All 
that happened was that Alice got entangled with her particle (and not 
just Alice,  her entire environment gets entangled with the state of her 
particle), which in turn was entangled with Bob's particle. So, Bob has 
the same probabilities for finding spin up or down, except that he can 
now measure the state of his particle by performing a measurement on 
Alice,  by asking her what she found for her spin.


It's not true that before Bob knows what Alice has found that only one 
of the two version's of Alice has arrived and that the information of 
her spin state is then already present in Bob's sector. This is not true 
in the MWI, decoherence simple means that you can't demonstrate the 
existence of the two versions of Alice via an interference experiment. 
But the inability to do so, doesn't by itself imply that only one 
version really exists.


Saibal

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Re: Consistency of Postulates of QM

[Bruno Marchal]

On 12 Nov 2017, at 07:57, Bruce Kellett wrote:


On 12/11/2017 5:39 pm, Brent Meeker wrote:

On 11/11/2017 9:56 PM, Bruce Kellett wrote:

On 12/11/2017 4:04 pm, Brent Meeker wrote:

On 11/11/2017 6:47 PM, Bruce Kellett wrote:

On 12/11/2017 4:34 am, John Clark wrote:
On Fri, Nov 10, 2017 at 7:08 PM, Alan Grayson  wrote:


​ ​ >> ​ That's not the measurement problem, its  
determining if how and why observation effects things. ​


​ > ​ Not to split hairs, but why we get what we get in  
quantum measurements, and how measurement outcomes come to be  
what they are, are the same problem IMO.


The measurement problem is not the ability or inability to  
predict exact outcomes, ​ ​ the measurement problem is  
defining what is ​ ​ and ​ ​ what ​ ​ is not a  
measurement and ​ ​ finding the ​ ​ minimum properties a  
system ​ ​ must ​ ​ have to be an observer.  
Nondeterminism is not a problem and there is no inconsistency  
at all regardless of what turns out to be true ​ ;​ if some  
effects have no cause and true randomness exists then that's  
just the way things are are ​ ​ and ​ ​t here is no  
resulting paradox and no question that needs answering.


​ The title of this thread is about the consistency of Quantum  
Mechanics, but far more important than QM is the ability of ANY  
theory to be compatible with experimental results, and one of  
those experiments shows the violation of Bell's Inequality. And  
that violation tells us that for ANY theory to be successful at  
explaining how the world works AT LEAST one of the following  
properties of that theory must be untrue:


1) Determinism
2) Locality
3) Realism

Is Many Worlds deterministic? Yes in the sense that it just  
follows the wave function and that is deterministic, it's only  
the collapse of the wave function that is nondeterministic and  
that never happens in Manny Worlds.


Is Many Worlds Local? Some say yes but I would say no because  
those other worlds are about as non-local as you can get, you  
can't get there even with infinite time on your side. But even  
if I'm wrong about locality Many Worlds would still be in the  
running for a successful theory because it is certainly not  
realistic.


I would agree with you that the many worlds account is non- 
local. The problem that MW faces is that the separate worlds  
split off when measurements are made at either end of the EPR  
experiment must somehow be made to match up appropriately when  
the two experimenters communicate. This requires coordination of  
separate worlds, which, as you say, is about as non-local as you  
can get.


The problem becomes particularly apparent if you consider an EPR  
experiment with time-like separation. Let Alice prepare an EPR  
pair in her laboratory, then measure the spin of one of the pair  
in some defined direction. She then takes the other member of  
the EPR pair down the corridor to her partner, Bob, and gets him  
to measure the spin projection in the same direction. If the two  
particles are independent, then both measurements give 50/50  
chances for up/down. After Alice measures her particle, she  
splits into Alice_up and Alice _down according to her result.  
Both copies then go to Bob's laboratory, which by then has also  
split according to Alice's result. So Alice_up meets Bob, but  
when he measures his particle, he still has 50/50 chances of  
either result. Unfortunately, the only result that is consistent  
with spin conservation is that if Alice got 'up', he must get  
'down', and vice verse (remember that the measurements are  
aligned by design).


Since Alice_up can't meet a Bob_up, there must be a non-local  
influence that determines Bob's result according to which Alice  
he meets. This is not removed be assuming no collapse and many  
worlds.


But Bruno's model assumes infinitely many worlds; some in which  
Alice sees up and Bob sees down and others in which Alice sees  
down and Bob sees up..."influence" doesn't really appear in the  
model because it's kind of block multiverse and there's some rule  
(conservation of angular momentum) that means up-up and down-down  
don't appear.  I think this is also true of t'Hooft's super- 
deterministic model because in that model there's nothing special  
about the event of Alice's measurement that needs to be  
communicated.  The idea of influence propagating from an event  
derives from the idea that Alice had "free-will" and so her  
choice had to be communicated from the measurement event.


That does not address the scenario I have outlined. In the time- 
like case, Alice_up meets Bob with a spin state that can result in  
either up or down; similarly Alice_down meets Bob with a spin  
state on which Bob's measurement can result in either up or down  
with 50% of each. There are only two worlds involved at that stage.


No, that's the point.  There are infinitely many "worlds" involved  
from the beginning.  There's no splitting.  It's all 

Re: Consistency of Postulates of QM

[John Clark]

On Sun, Nov 12, 2017 at 1:01 AM,  wrote:

​> ​
> What is your definition of non-realistic?
>

Nonrealistic means ​when something is not being observed it doesn't exist
in any one definite state.​

​ A photon ​hits a horizontally polarizing filter and the universe splits
in two if Many Worlds is right, in one the photon makes it through the
filter and the inhabitants of that world conclude it is 100% horizontally
polarized , in the other world it doesn't get through the filter and they
conclude it must have been 100% vertically polarized, but in the world
before the split, before it hit the filter, the inhabitants of that world
would conclude (if they believed in Many Worlds) that the photon did not
have any one definite polarized state at all.

​
>> ​>> ​
>> That is not unique to the MWI. In a accelerating  ​Einsteinian universe
>> such as ours energy is not conserved at the cosmological level.
>>
>
> ​> ​
> There was some unique condition that gave rise to our universe.
>

​The multiverse may have always existed, if so then nothing, unique or
otherwise, gave rise to it,​



> ​> ​
> MWI has it happening wily-nily when someone performs a slit experiment in
> a lab (and uncountably many times). Hardly a conservative interpretation
> IMO.
>

​Many Worlds is very conservative if the mathematics doesn't say ​
​anything about a wave collapse. And it doesn't.

​>> ​
>> they can't even say what is observation is. ​
>>
>
> ​> ​
> I can. They can. In a SG experiment, e.g., an observation occurs when the
> electron's spin state is aligned, or anti-aligned to the magnetic field.
>

​Observation is the wrong word if no observer is involved, then its just a
change and a change is the criteria Many Worlds uses. In MWI everything
that can happen does happen, so when a photon approaches 2 slits the
universe splits and one photon goes through the right slit and one goes
through the left slit. If after that the photons hit a photographic plate
(or a brick wall) then the photons no longer exist in either universe and
so they merge back together into one universe and this merger causes the
interference lines. If instead after passing the slits there is no
photographic plate (or brick wall) and the photons are allowed to continue
on into infinite space then the 2 universes remain different and remain
separated forever.

The universe splits because there is a difference, in one the photon went
through the left slit and in another it went through the right slit, and
the wave function never collapses it just keeps on going. And there is
nothing special about me, I split just like everything else in the
universe, the fact that I am conscious is irrelevant.  That's another great
advantage of Many Worlds, unlike Copenhagen it doesn't need to explain what
consciousness is or how it works because consciousness has nothing to do
with it.


> ​>> ​
>> Can only a person make a observation or can a cockroach collapse the wave
>> function too?
>>
>
> ​> ​
> Feynman is conclusive on this point. No person or cockroach needed; just
> an instrument to record the result.
>

​If an instrument is anything that can exist in at least 2 states then I
would be fine with that, but that sounds much more like Many Worlds than
Copenhagen. ​All that's needed is a change, any change, it need not be
anything as dramatic as a change in something as complex as a brain.

​> ​
> Does every event require an observer or instrument to witness it? I think
> not.
>

​I think ever observation requires a observer to witness a change, and
Copenhagen requires an observation to trigger the collapse of the wave
function. Many Worlds just requires a simple change to trigger a split, a
change in anything, and nothing triggers
the collapse o
​f​
the wave function
​ because the mathematics doesn't even hint at such a thing happening, the
Copenhagen people just tacked that on. Somebody said that Many Worlds is
cheap on assumptions but expensive in universes and I think that's true,
I'm a fan because universes are cheaper than assumptions. ​

  John K Clark

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Re: Consistency of Postulates of QM

[Bruno Marchal]

On 12 Nov 2017, at 03:47, Bruce Kellett wrote:


On 12/11/2017 4:34 am, John Clark wrote:
On Fri, Nov 10, 2017 at 7:08 PM, Alan Grayson  
 wrote:


​ ​ >> ​ That's not the measurement problem, its determining  
if how and why observation effects things. ​


​ > ​ Not to split hairs, but why we get what we get in quantum  
measurements, and how measurement outcomes come to be what they  
are, are the same problem IMO.


The measurement problem is not the ability or inability to predict  
exact outcomes, ​ ​ the measurement problem is defining what  
is ​ ​ and ​ ​ what ​ ​ is not a measurement and ​ ​  
finding the ​ ​ minimum properties a system ​ ​ must ​ ​  
have to be an observer. Nondeterminism is not a problem and there  
is no inconsistency at all regardless of what turns out to be  
true ​ ;​ if some effects have no cause and true randomness  
exists then that's just the way things are are ​ ​ and ​ ​t  
here is no resulting paradox and no question that needs answering.


​ The title of this thread is about the consistency of Quantum  
Mechanics, but far more important than QM is the ability of ANY  
theory to be compatible with experimental results, and one of those  
experiments shows the violation of Bell's Inequality. And that  
violation tells us that for ANY theory to be successful at  
explaining how the world works AT LEAST one of the following  
properties of that theory must be untrue:


1) Determinism
2) Locality
3) Realism

Is Many Worlds deterministic? Yes in the sense that it just follows  
the wave function and that is deterministic, it's only the collapse  
of the wave function that is nondeterministic and that never  
happens in Manny Worlds.


Is Many Worlds Local? Some say yes but I would say no because those  
other worlds are about as non-local as you can get, you can't get  
there even with infinite time on your side. But even if I'm wrong  
about locality Many Worlds would still be in the   
running for a successful theory because it is certainly not  
realistic.


I would agree with you that the many worlds account is non-local.  
The problem that MW faces is that the separate worlds split off when  
measurements are made at either end of the EPR experiment must  
somehow be made to match up appropriately when the two experimenters  
communicate. This requires coordination of separate worlds, which,  
as you say, is about as non-local as you can get.


OK, but without action at a distance. If you take into account the  
local propagation of the observers (treating them quantum  
mechanically), and the same for their "future" counterparts. The  
coordination is just kept locally by the observers. There is a strong  
"local" first person sharable non locality, but yet no physical action  
at a distance, nor problem with physical realism (albeit multiversal).






The problem becomes particularly apparent if you consider an EPR  
experiment with time-like separation. Let Alice prepare an EPR pair  
in her laboratory, then measure the spin of one of the pair in some  
defined direction. She then takes the other member of the EPR pair  
down the corridor to her partner, Bob, and gets him to measure the  
spin projection in the same direction. If the two particles are  
independent,

then both measurements give 50/50 chances for up/down.


OK. But they are not independent. After her measurement she is in a  
class of worlds with some definite result for both particle, with  
respect to the base up/down.





After Alice measures her particle, she splits into Alice_up and  
Alice _down according to her result. Both copies then go to Bob's  
laboratory, which by then has also split according to Alice's result.


OK.



So Alice_up meets Bob, but when he measures his particle, he still  
has 50/50 chances of either result.


I don't think so. Only if he got the time to do it before Alice splits  
has not rich him. But he would propagate a possibly "violating Bell"  
result to a different Alice, just by tyhe lienarity of the tensor  
products and evolution.





Unfortunately, the only result that is consistent with spin  
conservation is that if Alice got 'up', he must get 'down', and vice  
verse (remember that the measurements are aligned by design).


Yes.




Since Alice_up can't meet a Bob_up, there must be a non-local  
influence that determines Bob's result according to which Alice he  
meets. This is not removed be assuming no collapse and many worlds.


Of course, with time-like separation, the results can be explained  
by a local hidden variable, but no such explanation is available for  
space-like separated measurements, and the same explanation must be  
available for both cases.


But it is. Because the Alice and Bob moves locally, causally and lives  
always in the partition dictated by the result of ùeasurement, which  
propagate locally. In a pure space-like separation, you cannot even  
defined the identity of the 

Re: Consistency of Postulates of QM

[Brent Meeker]

On 11/12/2017 2:14 AM, smitra wrote:

On 12-11-2017 07:57, Bruce Kellett wrote:

On 12/11/2017 5:39 pm, Brent Meeker wrote:


On 11/11/2017 9:56 PM, Bruce Kellett wrote:
On 12/11/2017 4:04 pm, Brent Meeker wrote:
On 11/11/2017 6:47 PM, Bruce Kellett wrote:
On 12/11/2017 4:34 am, John Clark wrote:

On Fri, Nov 10, 2017 at 7:08 PM, Alan Grayson
 wrote:

​
​ >> ​ That's not the measurement problem, its determining if
how and why observation effects things. ​

​ > ​ Not to split hairs, but why we get what we get in quantum
measurements, and how measurement outcomes come to be what they are,
are the same problem IMO.


 The measurement problem is not the ability or inability to predict
exact outcomes,
​ ​ the measurement problem is defining what is
​ ​ and
​ ​ what
​ ​ is not a measurement and
​ ​ finding the
​ ​ minimum properties a system
​ ​ must
​ ​ have to be an observer. Nondeterminism is not a problem and
there is no inconsistency at all regardless of what turns out to be
true
​ ;​ if some effects have no cause and true randomness exists then
that's just the way things are are
​ ​ and
​ ​t here is no resulting paradox and no question that needs
answering.

​ The title of this thread is about the consistency of Quantum
Mechanics, but far more important than QM is the ability of ANY theory
to be compatible with experimental results, and one of those
experiments shows the violation of Bell's Inequality. And that
violation tells us that for ANY theory to be successful at explaining
how the world works AT LEAST one of the following properties of that
theory must be untrue:

1) Determinism
2) Locality
3) Realism

Is Many Worlds deterministic? Yes in the sense that it just follows
the wave function and that is deterministic, it's only the collapse of
the wave function that is nondeterministic and that never happens in
Manny Worlds.

Is Many Worlds Local? Some say yes but I would say no because those
other worlds are about as non-local as you can get, you can't get
there even with infinite time on your side. But even if I'm wrong
about locality Many Worlds would still be in the running for a
successful theory because it is certainly not realistic.

 I would agree with you that the many worlds account is non-local. The
problem that MW faces is that the separate worlds split off when
measurements are made at either end of the EPR experiment must somehow
be made to match up appropriately when the two experimenters
communicate. This requires coordination of separate worlds, which, as
you say, is about as non-local as you can get.

 The problem becomes particularly apparent if you consider an EPR
experiment with time-like separation. Let Alice prepare an EPR pair in
her laboratory, then measure the spin of one of the pair in some
defined direction. She then takes the other member of the EPR pair
down the corridor to her partner, Bob, and gets him to measure the
spin projection in the same direction. If the two particles are
independent, then both measurements give 50/50 chances for up/down.
After Alice measures her particle, she splits into Alice_up and Alice
_down according to her result. Both copies then go to Bob's
laboratory, which by then has also split according to Alice's result.
So Alice_up meets Bob, but when he measures his particle, he still has
50/50 chances of either result. Unfortunately, the only result that is
consistent with spin conservation is that if Alice got 'up', he must
get 'down', and vice verse (remember that the measurements are aligned
by design).

 Since Alice_up can't meet a Bob_up, there must be a non-local
influence that determines Bob's result according to which Alice he
meets. This is not removed be assuming no collapse and many worlds.

 But Bruno's model assumes infinitely many worlds; some in which Alice
sees up and Bob sees down and others in which Alice sees down and Bob
sees up..."influence" doesn't really appear in the model because it's
kind of block multiverse and there's some rule (conservation of
angular momentum) that means up-up and down-down don't appear. I
think this is also true of t'Hooft's super-deterministic model because
in that model there's nothing special about the event of Alice's
measurement that needs to be communicated.  The idea of influence
propagating from an event derives from the idea that Alice had
"free-will" and so her choice had to be communicated from the
measurement event.

 That does not address the scenario I have outlined. In the time-like
case, Alice_up meets Bob with a spin state that can result in either
up or down; similarly Alice_down meets Bob with a spin state on which
Bob's measurement can result in either up or down with 50% of each.
There are only two worlds involved at that stage.
 No, that's the point.  There are infinitely many "worlds" involved
from the beginning.  There's no splitting.  It's all predetermined.

 That is simply not true. There are, by construction, only two worlds
in this scenario 

Re: Consistency of Postulates of QM

[Brent Meeker]

On 11/11/2017 10:57 PM, Bruce Kellett wrote:

On 12/11/2017 5:39 pm, Brent Meeker wrote:

On 11/11/2017 9:56 PM, Bruce Kellett wrote:

On 12/11/2017 4:04 pm, Brent Meeker wrote:

On 11/11/2017 6:47 PM, Bruce Kellett wrote:

On 12/11/2017 4:34 am, John Clark wrote:
On Fri, Nov 10, 2017 at 7:08 PM, Alan Grayson 
wrote:


​
​ >> ​
That's not the measurement problem, its determining if
how and why observation effects things. ​


​ > ​
Not to split hairs, but why we get what we get in quantum
measurements, and how measurement outcomes come to be what
they are, are the same problem IMO.


The measurement problem is not the ability or inability to 
predict exact outcomes,

​ ​
the measurement problem is defining what is
​ ​
and
​ ​
what
​ ​
is not a measurement and
​ ​
finding the
​ ​
minimum properties a system
​ ​
must
​ ​
have to be an observer. Nondeterminism is not a problem and there 
is no inconsistency at all regardless of what turns out to be true

​ ;​
if some effects have no cause and true randomness exists then 
that's just the way things are are

​ ​
and
​ ​t
here is no resulting paradox and no question that needs answering.

​
The title of this thread is about the consistency of Quantum 
Mechanics, but far more important than QM is the ability of ANY 
theory to be compatible with experimental results, and one of 
those experiments shows the violation of Bell's Inequality. And 
that violation tells us that for ANY theory to be successful at 
explaining how the world works AT LEAST one of the following 
properties of that theory must be untrue:


1) Determinism
2) Locality
3) Realism

Is Many Worlds deterministic? Yes in the sense that it just 
follows the wave function and that is deterministic, it's only 
the collapse of the wave function that is nondeterministic and 
that never happens in Manny Worlds.


Is Many Worlds Local? Some say yes but I would say no 
because those other worlds are about as non-local as you can get, 
you can't get there even with infinite time on your side. But 
even if I'm wrong about locality Many Worlds would still be in 
the running for a successful theory because it is certainly not 
realistic.


I would agree with you that the many worlds account is non-local. 
The problem that MW faces is that the separate worlds split off 
when measurements are made at either end of the EPR experiment 
must somehow be made to match up appropriately when the two 
experimenters communicate. This requires coordination of separate 
worlds, which, as you say, is about as non-local as you can get.


The problem becomes particularly apparent if you consider an EPR 
experiment with time-like separation. Let Alice prepare an EPR 
pair in her laboratory, then measure the spin of one of the pair 
in some defined direction. She then takes the other member of the 
EPR pair down the corridor to her partner, Bob, and gets him to 
measure the spin projection in the same direction. If the two 
particles are independent, then both measurements give 50/50 
chances for up/down. After Alice measures her particle, she splits 
into Alice_up and Alice _down according to her result. Both copies 
then go to Bob's laboratory, which by then has also split 
according to Alice's result. So Alice_up meets Bob, but when he 
measures his particle, he still has 50/50 chances of either 
result. Unfortunately, the only result that is consistent with 
spin conservation is that if Alice got 'up', he must get 'down', 
and vice verse (remember that the measurements are aligned by design).


Since Alice_up can't meet a Bob_up, there must be a non-local 
influence that determines Bob's result according to which Alice he 
meets. This is not removed be assuming no collapse and many worlds.


But Bruno's model assumes infinitely many worlds; some in which 
Alice sees up and Bob sees down and others in which Alice sees down 
and Bob sees up..."influence" doesn't really appear in the model 
because it's kind of block multiverse and there's some rule 
(conservation of angular momentum) that means up-up and down-down 
don't appear.  I think this is also true of t'Hooft's 
super-deterministic model because in that model there's nothing 
special about the event of Alice's measurement that needs to be 
communicated.  The idea of influence propagating from an event 
derives from the idea that Alice had "free-will" and so her choice 
had to be communicated from the measurement event.


That does not address the scenario I have outlined. In the time-like 
case, Alice_up meets Bob with a spin state that can result in either 
up or down; similarly Alice_down meets Bob with a spin state on 
which Bob's measurement can result in either up or down with 50% of 
each. There are only two worlds involved at that stage. 


No, that's the point.  There are infinitely many "worlds" involved 
from the beginning.  There's no splitting.  It's all predetermined.


That is simply 

Re: Consistency of Postulates of QM

[Bruce Kellett]

On 12/11/2017 9:14 pm, smitra wrote:

On 12-11-2017 07:57, Bruce Kellett wrote:

On 12/11/2017 5:39 pm, Brent Meeker wrote:


In Bruno's model the "influence at a distance" is determing which
world you're in.


 If that means anything at all, it is still non-local because Bruno
has to rule out the worlds in which angular momentum is not conserved;
 he has not shown how he can do this. If it is simply that you cannot
find yourself in a world in which AM is not conserved, then that is
just an unabashed appeal to magic, since such worlds have not been
shown not to exist.

 Bruce


There are two correlated copies of Alice and Bob induced by the 
correlated spins, there is nothing nonlocal about that in the MWI. 
There is only a non- locality problem here if you assume a collapse 
interpretation of QM. In the MWI the correlation arises via an 
originally local common cause.


There is no collapse assumption in anything that I have written about 
this scenario. What is the local common cause in MWI? Is that a local 
hidden variable? Such would work in the time-like case, but not in 
general -- that is Bell's result.


But you have still not answered the fundamental question as to what 
causes Bob to necessarily measure spin down when Alice joins him with a 
spin-up result? What turns Bob's particle from an unpolarized to a 
polarized state so that the probabilities change from 50/50 to 100% for 
spin down?


Bruce

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Re: Consistency of Postulates of QM

[smitra]

On 12-11-2017 07:57, Bruce Kellett wrote:

On 12/11/2017 5:39 pm, Brent Meeker wrote:


On 11/11/2017 9:56 PM, Bruce Kellett wrote:
On 12/11/2017 4:04 pm, Brent Meeker wrote:
On 11/11/2017 6:47 PM, Bruce Kellett wrote:
On 12/11/2017 4:34 am, John Clark wrote:

On Fri, Nov 10, 2017 at 7:08 PM, Alan Grayson
 wrote:

​
​ >> ​ That's not the measurement problem, its determining if
how and why observation effects things. ​

​ > ​ Not to split hairs, but why we get what we get in quantum
measurements, and how measurement outcomes come to be what they are,
are the same problem IMO.


 The measurement problem is not the ability or inability to predict
exact outcomes,
​ ​ the measurement problem is defining what is
​ ​ and
​ ​ what
​ ​ is not a measurement and
​ ​ finding the
​ ​ minimum properties a system
​ ​ must
​ ​ have to be an observer. Nondeterminism is not a problem and
there is no inconsistency at all regardless of what turns out to be
true
​ ;​ if some effects have no cause and true randomness exists then
that's just the way things are are
​ ​ and
​ ​t here is no resulting paradox and no question that needs
answering.

​ The title of this thread is about the consistency of Quantum
Mechanics, but far more important than QM is the ability of ANY theory
to be compatible with experimental results, and one of those
experiments shows the violation of Bell's Inequality. And that
violation tells us that for ANY theory to be successful at explaining
how the world works AT LEAST one of the following properties of that
theory must be untrue:

1) Determinism
2) Locality
3) Realism

Is Many Worlds deterministic? Yes in the sense that it just follows
the wave function and that is deterministic, it's only the collapse of
the wave function that is nondeterministic and that never happens in
Manny Worlds.

Is Many Worlds Local? Some say yes but I would say no because those
other worlds are about as non-local as you can get, you can't get
there even with infinite time on your side. But even if I'm wrong
about locality Many Worlds would still be in the running for a
successful theory because it is certainly not realistic.

 I would agree with you that the many worlds account is non-local. The
problem that MW faces is that the separate worlds split off when
measurements are made at either end of the EPR experiment must somehow
be made to match up appropriately when the two experimenters
communicate. This requires coordination of separate worlds, which, as
you say, is about as non-local as you can get.

 The problem becomes particularly apparent if you consider an EPR
experiment with time-like separation. Let Alice prepare an EPR pair in
her laboratory, then measure the spin of one of the pair in some
defined direction. She then takes the other member of the EPR pair
down the corridor to her partner, Bob, and gets him to measure the
spin projection in the same direction. If the two particles are
independent, then both measurements give 50/50 chances for up/down.
After Alice measures her particle, she splits into Alice_up and Alice
_down according to her result. Both copies then go to Bob's
laboratory, which by then has also split according to Alice's result.
So Alice_up meets Bob, but when he measures his particle, he still has
50/50 chances of either result. Unfortunately, the only result that is
consistent with spin conservation is that if Alice got 'up', he must
get 'down', and vice verse (remember that the measurements are aligned
by design).

 Since Alice_up can't meet a Bob_up, there must be a non-local
influence that determines Bob's result according to which Alice he
meets. This is not removed be assuming no collapse and many worlds.

 But Bruno's model assumes infinitely many worlds; some in which Alice
sees up and Bob sees down and others in which Alice sees down and Bob
sees up..."influence" doesn't really appear in the model because it's
kind of block multiverse and there's some rule (conservation of
angular momentum) that means up-up and down-down don't appear.  I
think this is also true of t'Hooft's super-deterministic model because
in that model there's nothing special about the event of Alice's
measurement that needs to be communicated.  The idea of influence
propagating from an event derives from the idea that Alice had
"free-will" and so her choice had to be communicated from the
measurement event.

 That does not address the scenario I have outlined. In the time-like
case, Alice_up meets Bob with a spin state that can result in either
up or down; similarly Alice_down meets Bob with a spin state on which
Bob's measurement can result in either up or down with 50% of each.
There are only two worlds involved at that stage.
 No, that's the point.  There are infinitely many "worlds" involved
from the beginning.  There's no splitting.  It's all predetermined.

 That is simply not true. There are, by construction, only two worlds
in this scenario before Bob makes his measurment, and that 

Re: Consistency of Postulates of QM

[Bruce Kellett]

On 12/11/2017 5:39 pm, Brent Meeker wrote:

On 11/11/2017 9:56 PM, Bruce Kellett wrote:

On 12/11/2017 4:04 pm, Brent Meeker wrote:

On 11/11/2017 6:47 PM, Bruce Kellett wrote:

On 12/11/2017 4:34 am, John Clark wrote:
On Fri, Nov 10, 2017 at 7:08 PM, Alan Grayson 
wrote:


​
​ >> ​
That's not the measurement problem, its determining if how
and why observation effects things. ​


​ > ​
Not to split hairs, but why we get what we get in quantum
measurements, and how measurement outcomes come to be what
they are, are the same problem IMO.


The measurement problem is not the ability or inability to predict 
exact outcomes,

​ ​
the measurement problem is defining what is
​ ​
and
​ ​
what
​ ​
is not a measurement and
​ ​
finding the
​ ​
minimum properties a system
​ ​
must
​ ​
have to be an observer. Nondeterminism is not a problem and there 
is no inconsistency at all regardless of what turns out to be true

​ ;​
if some effects have no cause and true randomness exists then 
that's just the way things are are

​ ​
and
​ ​t
here is no resulting paradox and no question that needs answering.

​
The title of this thread is about the consistency of Quantum 
Mechanics, but far more important than QM is the ability of ANY 
theory to be compatible with experimental results, and one of 
those experiments shows the violation of Bell's Inequality. And 
that violation tells us that for ANY theory to be successful at 
explaining how the world works AT LEAST one of the following 
properties of that theory must be untrue:


1) Determinism
2) Locality
3) Realism

Is Many Worlds deterministic? Yes in the sense that it just 
follows the wave function and that is deterministic, it's only the 
collapse of the wave function that is nondeterministic and that 
never happens in Manny Worlds.


Is Many Worlds Local? Some say yes but I would say no 
because those other worlds are about as non-local as you can get, 
you can't get there even with infinite time on your side. But even 
if I'm wrong about locality Many Worlds would still be in the 
running for a successful theory because it is certainly not realistic.


I would agree with you that the many worlds account is non-local. 
The problem that MW faces is that the separate worlds split off 
when measurements are made at either end of the EPR experiment must 
somehow be made to match up appropriately when the two 
experimenters communicate. This requires coordination of separate 
worlds, which, as you say, is about as non-local as you can get.


The problem becomes particularly apparent if you consider an EPR 
experiment with time-like separation. Let Alice prepare an EPR pair 
in her laboratory, then measure the spin of one of the pair in some 
defined direction. She then takes the other member of the EPR pair 
down the corridor to her partner, Bob, and gets him to measure the 
spin projection in the same direction. If the two particles are 
independent, then both measurements give 50/50 chances for up/down. 
After Alice measures her particle, she splits into Alice_up and 
Alice _down according to her result. Both copies then go to Bob's 
laboratory, which by then has also split according to Alice's 
result. So Alice_up meets Bob, but when he measures his particle, 
he still has 50/50 chances of either result. Unfortunately, the 
only result that is consistent with spin conservation is that if 
Alice got 'up', he must get 'down', and vice verse (remember that 
the measurements are aligned by design).


Since Alice_up can't meet a Bob_up, there must be a non-local 
influence that determines Bob's result according to which Alice he 
meets. This is not removed be assuming no collapse and many worlds.


But Bruno's model assumes infinitely many worlds; some in which 
Alice sees up and Bob sees down and others in which Alice sees down 
and Bob sees up..."influence" doesn't really appear in the model 
because it's kind of block multiverse and there's some rule 
(conservation of angular momentum) that means up-up and down-down 
don't appear.  I think this is also true of t'Hooft's 
super-deterministic model because in that model there's nothing 
special about the event of Alice's measurement that needs to be 
communicated.  The idea of influence propagating from an event 
derives from the idea that Alice had "free-will" and so her choice 
had to be communicated from the measurement event.


That does not address the scenario I have outlined. In the time-like 
case, Alice_up meets Bob with a spin state that can result in either 
up or down; similarly Alice_down meets Bob with a spin state on which 
Bob's measurement can result in either up or down with 50% of each. 
There are only two worlds involved at that stage. 


No, that's the point.  There are infinitely many "worlds" involved 
from the beginning.  There's no splitting.  It's all predetermined.


That is simply not true. There are, by construction, only two 

Re: Consistency of Postulates of QM

[Brent Meeker]

On 11/11/2017 9:56 PM, Bruce Kellett wrote:

On 12/11/2017 4:04 pm, Brent Meeker wrote:

On 11/11/2017 6:47 PM, Bruce Kellett wrote:

On 12/11/2017 4:34 am, John Clark wrote:
On Fri, Nov 10, 2017 at 7:08 PM, Alan Grayson 
wrote:


​
​ >> ​
That's not the measurement problem, its determining if how
and why observation effects things. ​


​ > ​
Not to split hairs, but why we get what we get in quantum
measurements, and how measurement outcomes come to be what they
are, are the same problem IMO.


The measurement problem is not the ability or inability to predict 
exact outcomes,

​ ​
the measurement problem is defining what is
​ ​
and
​ ​
what
​ ​
is not a measurement and
​ ​
finding the
​ ​
minimum properties a system
​ ​
must
​ ​
have to be an observer. Nondeterminism is not a problem and there 
is no inconsistency at all regardless of what turns out to be true

​ ;​
if some effects have no cause and true randomness exists then 
that's just the way things are are

​ ​
and
​ ​t
here is no resulting paradox and no question that needs answering.

​
The title of this thread is about the consistency of Quantum 
Mechanics, but far more important than QM is the ability of ANY 
theory to be compatible with experimental results, and one of those 
experiments shows the violation of Bell's Inequality. And that 
violation tells us that for ANY theory to be successful at 
explaining how the world works AT LEAST one of the following 
properties of that theory must be untrue:


1) Determinism
2) Locality
3) Realism

Is Many Worlds deterministic? Yes in the sense that it just follows 
the wave function and that is deterministic, it's only the collapse 
of the wave function that is nondeterministic and that never 
happens in Manny Worlds.


Is Many Worlds Local? Some say yes but I would say no because those 
other worlds are about as non-local as you can get, you can't get 
there even with infinite time on your side. But even if I'm wrong 
about locality Many Worlds would still be in the running for a 
successful theory because it is certainly not realistic.


I would agree with you that the many worlds account is non-local. 
The problem that MW faces is that the separate worlds split off when 
measurements are made at either end of the EPR experiment must 
somehow be made to match up appropriately when the two experimenters 
communicate. This requires coordination of separate worlds, which, 
as you say, is about as non-local as you can get.


The problem becomes particularly apparent if you consider an EPR 
experiment with time-like separation. Let Alice prepare an EPR pair 
in her laboratory, then measure the spin of one of the pair in some 
defined direction. She then takes the other member of the EPR pair 
down the corridor to her partner, Bob, and gets him to measure the 
spin projection in the same direction. If the two particles are 
independent, then both measurements give 50/50 chances for up/down. 
After Alice measures her particle, she splits into Alice_up and 
Alice _down according to her result. Both copies then go to Bob's 
laboratory, which by then has also split according to Alice's 
result. So Alice_up meets Bob, but when he measures his particle, he 
still has 50/50 chances of either result. Unfortunately, the only 
result that is consistent with spin conservation is that if Alice 
got 'up', he must get 'down', and vice verse (remember that the 
measurements are aligned by design).


Since Alice_up can't meet a Bob_up, there must be a non-local 
influence that determines Bob's result according to which Alice he 
meets. This is not removed be assuming no collapse and many worlds.


But Bruno's model assumes infinitely many worlds; some in which Alice 
sees up and Bob sees down and others in which Alice sees down and Bob 
sees up..."influence" doesn't really appear in the model because it's 
kind of block multiverse and there's some rule (conservation of 
angular momentum) that means up-up and down-down don't appear.  I 
think this is also true of t'Hooft's super-deterministic model 
because in that model there's nothing special about the event of 
Alice's measurement that needs to be communicated.  The idea of 
influence propagating from an event derives from the idea that Alice 
had "free-will" and so her choice had to be communicated from the 
measurement event.


That does not address the scenario I have outlined. In the time-like 
case, Alice_up meets Bob with a spin state that can result in either 
up or down; similarly Alice_down meets Bob with a spin state on which 
Bob's measurement can result in either up or down with 50% of each. 
There are only two worlds involved at that stage. 


No, that's the point.  There are infinitely many "worlds" involved from 
the beginning.  There's no splitting.  It's all predetermined.


The question is, how does Bob with Alice_up not get an up result, 
contradicting conservation of angular 

Re: Consistency of Postulates of QM

[agrayson2000]

On Saturday, November 11, 2017 at 9:37:28 PM UTC-7, John Clark wrote:
>
> On Sat, Nov 11, 2017 at 3:31 PM,  
> wrote:
>
> ​> ​
>> Why not just assume the wf collapses by an as-yet unknown process?
>>
>
> ​You can do that if you want, but Bell proved that if his inequality is 
> violated, and we now know from experiment that it is, and if that unknown 
> process is deterministic then the world is non-local or non-realistic or 
> both.   
>

Bell showed, and experiments confirm, that our universe is non-local. I 
think that's the case whether or not the proposed collapse process is 
deterministic. But if it is deterministic, it messes up physics as Brent 
earlier indicated. So I suppose it can't be deterministic. And if not 
deterministic, I think we're back to collapse, and there doesn't seem to be 
any way to resolve the randomness, the resolution of which I had in mind. 

What is your definition of non-realistic? TIA.

> ​
>  
>  
>
>> ​> ​
>> Then, unlike MWI, you have a theory within the realm of testable physics 
>> and no need to explain where the energy comes from to create those other 
>> worlds
>>
>
> ​That is not unique to the MWI. In a accelerating  ​Einsteinian universe 
> such as ours energy is not conserved at the cosmological level.
>

There was some unique condition that gave rise to our universe. MWI has it 
happening wily-nily when someone performs a slit experiment in a lab (and 
uncountably many times). Hardly a conservative interpretation IMO.  

>  
>
>> ​> ​
>> Is collapse so repugnant  (how so?)
>>
>
> ​It's repugnant because the mathematics say nothing about a collapse, the C
> openhagen
> ​ people just wave there arms and say that it does when a observation is 
> made, and they can't even say what is observation is. ​
>

I can. They can. In a SG experiment, e.g., an observation occurs when the 
electron's spin state is aligned, or anti-aligned to the magnetic field. 
 

> Can only a person make a observation or can a cockroach collapse the wave 
> function too? 
>

Feynman is conclusive on this point. No person or cockroach needed; just an 
instrument to record the result.
 

> And what observed the universe at the Big Bang?  If it's God what is 
> observing God? The MWI is actually very conservative, it just assumes the 
> mathematics means what it says and it doesn't stick on a bunch of other 
> stuff as Copenhagen does. 
>

Does every event require an observer or instrument to witness it? I think 
not. 

>  
>
>> ​> ​
>> that one has to grasp at a cure that ostensibly is hugely worse than the 
>> alleged disease
>> ​ ​
>>  Inquiring minds want to know.
>>
>
> ​Whatever the truth turns out to be one thing is certain, it will be weird.
>
> John K Clark ​
>  
>
>
>
>

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Re: Consistency of Postulates of QM

[Bruce Kellett]

On 12/11/2017 4:04 pm, Brent Meeker wrote:

On 11/11/2017 6:47 PM, Bruce Kellett wrote:

On 12/11/2017 4:34 am, John Clark wrote:
On Fri, Nov 10, 2017 at 7:08 PM, Alan Grayson 
wrote:


​
​ >> ​
That's not the measurement problem, its determining if how
and why observation effects things. ​


​ > ​
Not to split hairs, but why we get what we get in quantum
measurements, and how measurement outcomes come to be what they
are, are the same problem IMO.


The measurement problem is not the ability or inability to predict 
exact outcomes,

​ ​
the measurement problem is defining what is
​ ​
and
​ ​
what
​ ​
is not a measurement and
​ ​
finding the
​ ​
minimum properties a system
​ ​
must
​ ​
have to be an observer. Nondeterminism is not a problem and there is 
no inconsistency at all regardless of what turns out to be true

​ ;​
if some effects have no cause and true randomness exists then that's 
just the way things are are

​ ​
and
​ ​t
here is no resulting paradox and no question that needs answering.

​
The title of this thread is about the consistency of Quantum 
Mechanics, but far more important than QM is the ability of ANY 
theory to be compatible with experimental results, and one of those 
experiments shows the violation of Bell's Inequality. And that 
violation tells us that for ANY theory to be successful at 
explaining how the world works AT LEAST one of the following 
properties of that theory must be untrue:


1) Determinism
2) Locality
3) Realism

Is Many Worlds deterministic? Yes in the sense that it just follows 
the wave function and that is deterministic, it's only the collapse 
of the wave function that is nondeterministic and that never happens 
in Manny Worlds.


Is Many Worlds Local? Some say yes but I would say no because those 
other worlds are about as non-local as you can get, you can't get 
there even with infinite time on your side. But even if I'm wrong 
about locality Many Worlds would still be in the running for a 
successful theory because it is certainly not realistic.


I would agree with you that the many worlds account is non-local. The 
problem that MW faces is that the separate worlds split off when 
measurements are made at either end of the EPR experiment must 
somehow be made to match up appropriately when the two experimenters 
communicate. This requires coordination of separate worlds, which, as 
you say, is about as non-local as you can get.


The problem becomes particularly apparent if you consider an EPR 
experiment with time-like separation. Let Alice prepare an EPR pair 
in her laboratory, then measure the spin of one of the pair in some 
defined direction. She then takes the other member of the EPR pair 
down the corridor to her partner, Bob, and gets him to measure the 
spin projection in the same direction. If the two particles are 
independent, then both measurements give 50/50 chances for up/down. 
After Alice measures her particle, she splits into Alice_up and Alice 
_down according to her result. Both copies then go to Bob's 
laboratory, which by then has also split according to Alice's result. 
So Alice_up meets Bob, but when he measures his particle, he still 
has 50/50 chances of either result. Unfortunately, the only result 
that is consistent with spin conservation is that if Alice got 'up', 
he must get 'down', and vice verse (remember that the measurements 
are aligned by design).


Since Alice_up can't meet a Bob_up, there must be a non-local 
influence that determines Bob's result according to which Alice he 
meets. This is not removed be assuming no collapse and many worlds.


But Bruno's model assumes infinitely many worlds; some in which Alice 
sees up and Bob sees down and others in which Alice sees down and Bob 
sees up..."influence" doesn't really appear in the model because it's 
kind of block multiverse and there's some rule (conservation of 
angular momentum) that means up-up and down-down don't appear.  I 
think this is also true of t'Hooft's super-deterministic model because 
in that model there's nothing special about the event of Alice's 
measurement that needs to be communicated.  The idea of influence 
propagating from an event derives from the idea that Alice had 
"free-will" and so her choice had to be communicated from the 
measurement event.


That does not address the scenario I have outlined. In the time-like 
case, Alice_up meets Bob with a spin state that can result in either up 
or down; similarly Alice_down meets Bob with a spin state on which Bob's 
measurement can result in either up or down with 50% of each. There are 
only two worlds involved at that stage. The question is, how does Bob 
with Alice_up not get an up result, contradicting conservation of 
angular momentum. Similarly, how does Bob with Alice_down not get a down 
result. Since the measurement axes are explicitly aligned in this case, 
the 'up-up' and 'down-down' observations are 

Re: Consistency of Postulates of QM

[Brent Meeker]

On 11/11/2017 6:47 PM, Bruce Kellett wrote:

On 12/11/2017 4:34 am, John Clark wrote:
On Fri, Nov 10, 2017 at 7:08 PM, Alan Grayson 
wrote:


​
​ >> ​
That's not the measurement problem, its determining if how
and why observation effects things. ​


​ > ​
Not to split hairs, but why we get what we get in quantum
measurements, and how measurement outcomes come to be what they
are, are the same problem IMO.


The measurement problem is not the ability or inability to predict 
exact outcomes,

​ ​
the measurement problem is defining what is
​ ​
and
​ ​
what
​ ​
is not a measurement and
​ ​
finding the
​ ​
minimum properties a system
​ ​
must
​ ​
have to be an observer. Nondeterminism is not a problem and there is 
no inconsistency at all regardless of what turns out to be true

​ ;​
if some effects have no cause and true randomness exists then that's 
just the way things are are

​ ​
and
​ ​t
here is no resulting paradox and no question that needs answering.

​
The title of this thread is about the consistency of Quantum 
Mechanics, but far more important than QM is the ability of ANY 
theory to be compatible with experimental results, and one of those 
experiments shows the violation of Bell's Inequality. And that 
violation tells us that for ANY theory to be successful at explaining 
how the world works AT LEAST one of the following properties of that 
theory must be untrue:


1) Determinism
2) Locality
3) Realism

Is Many Worlds deterministic? Yes in the sense that it just follows 
the wave function and that is deterministic, it's only the collapse 
of the wave function that is nondeterministic and that never happens 
in Manny Worlds.


Is Many Worlds Local? Some say yes but I would say no because those 
other worlds are about as non-local as you can get, you can't get 
there even with infinite time on your side. But even if I'm wrong 
about locality Many Worlds would still be in the running for a 
successful theory because it is certainly not realistic.


I would agree with you that the many worlds account is non-local. The 
problem that MW faces is that the separate worlds split off when 
measurements are made at either end of the EPR experiment must somehow 
be made to match up appropriately when the two experimenters 
communicate. This requires coordination of separate worlds, which, as 
you say, is about as non-local as you can get.


The problem becomes particularly apparent if you consider an EPR 
experiment with time-like separation. Let Alice prepare an EPR pair in 
her laboratory, then measure the spin of one of the pair in some 
defined direction. She then takes the other member of the EPR pair 
down the corridor to her partner, Bob, and gets him to measure the 
spin projection in the same direction. If the two particles are 
independent, then both measurements give 50/50 chances for up/down. 
After Alice measures her particle, she splits into Alice_up and Alice 
_down according to her result. Both copies then go to Bob's 
laboratory, which by then has also split according to Alice's result. 
So Alice_up meets Bob, but when he measures his particle, he still has 
50/50 chances of either result. Unfortunately, the only result that is 
consistent with spin conservation is that if Alice got 'up', he must 
get 'down', and vice verse (remember that the measurements are aligned 
by design).


Since Alice_up can't meet a Bob_up, there must be a non-local 
influence that determines Bob's result according to which Alice he 
meets. This is not removed be assuming no collapse and many worlds.


But Bruno's model assumes infinitely many worlds; some in which Alice 
sees up and Bob sees down and others in which Alice sees down and Bob 
sees up..."influence" doesn't really appear in the model because it's 
kind of block multiverse and there's some rule (conservation of angular 
momentum) that means up-up and down-down don't appear.  I think this is 
also true of t'Hooft's super-deterministic model because in that model 
there's nothing special about the event of Alice's measurement that 
needs to be communicated.  The idea of influence propagating from an 
event derives from the idea that Alice had "free-will" and so her choice 
had to be communicated from the measurement event.


Brent



Of course, with time-like separation, the results can be explained by 
a local hidden variable, but no such explanation is available for 
space-like separated measurements, and the same explanation must be 
available for both cases. Since non-locality is still present for 
time-like separations, it must be present in all cases. So many worlds 
do not eliminate non-locality in Bell-pair measurements.


Bruce

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Re: Consistency of Postulates of QM

[John Clark]

On Sat, Nov 11, 2017 at 3:31 PM,  wrote:

​> ​
> Why not just assume the wf collapses by an as-yet unknown process?
>

​You can do that if you want, but Bell proved that if his inequality is
violated, and we now know from experiment that it is, and if that unknown
process is deterministic then the world is non-local or non-realistic or
both.   ​



> ​> ​
> Then, unlike MWI, you have a theory within the realm of testable physics
> and no need to explain where the energy comes from to create those other
> worlds
>

​That is not unique to the MWI. In a accelerating  ​Einsteinian universe
such as ours energy is not conserved at the cosmological level.


> ​> ​
> Is collapse so repugnant  (how so?)
>

​It's repugnant because the mathematics say nothing about a collapse, the C
openhagen
​ people just wave there arms and say that it does when a observation is
made, and they can't even say what is observation is. ​Can only a person
make a observation or can a cockroach collapse the wave function too? And
what observed the universe at the Big Bang?  If it's God what is observing
God? The MWI is actually very conservative, it just assumes the mathematics
means what it says and it doesn't stick on a bunch of other stuff as
Copenhagen does.


> ​> ​
> that one has to grasp at a cure that ostensibly is hugely worse than the
> alleged disease
> ​ ​
>  Inquiring minds want to know.
>

​Whatever the truth turns out to be one thing is certain, it will be weird.

John K Clark ​

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Re: Consistency of Postulates of QM

[Bruce Kellett]

On 12/11/2017 4:34 am, John Clark wrote:
On Fri, Nov 10, 2017 at 7:08 PM, Alan Grayson 
wrote:


​
​ >> ​
That's not the measurement problem, its determining if how and
why observation effects things. ​


​ > ​
Not to split hairs, but why we get what we get in quantum
measurements, and how measurement outcomes come to be what they
are, are the same problem IMO.


The measurement problem is not the ability or inability to predict 
exact outcomes,

​ ​
the measurement problem is defining what is
​ ​
and
​ ​
what
​ ​
is not a measurement and
​ ​
finding the
​ ​
minimum properties a system
​ ​
must
​ ​
have to be an observer. Nondeterminism is not a problem and there is 
no inconsistency at all regardless of what turns out to be true

​ ;​
if some effects have no cause and true randomness exists then that's 
just the way things are are

​ ​
and
​ ​t
here is no resulting paradox and no question that needs answering.

​
The title of this thread is about the consistency of Quantum 
Mechanics, but far more important than QM is the ability of ANY theory 
to be compatible with experimental results, and one of those 
experiments shows the violation of Bell's Inequality. And that 
violation tells us that for ANY theory to be successful at explaining 
how the world works AT LEAST one of the following properties of that 
theory must be untrue:


1) Determinism
2) Locality
3) Realism

Is Many Worlds deterministic? Yes in the sense that it just follows 
the wave function and that is deterministic, it's only the collapse of 
the wave function that is nondeterministic and that never happens in 
Manny Worlds.


Is Many Worlds Local? Some say yes but I would say no because those 
other worlds are about as non-local as you can get, you can't get 
there even with infinite time on your side. But even if I'm wrong 
about locality Many Worlds would still be in the running for a 
successful theory because it is certainly not realistic.


I would agree with you that the many worlds account is non-local. The 
problem that MW faces is that the separate worlds split off when 
measurements are made at either end of the EPR experiment must somehow 
be made to match up appropriately when the two experimenters 
communicate. This requires coordination of separate worlds, which, as 
you say, is about as non-local as you can get.


The problem becomes particularly apparent if you consider an EPR 
experiment with time-like separation. Let Alice prepare an EPR pair in 
her laboratory, then measure the spin of one of the pair in some defined 
direction. She then takes the other member of the EPR pair down the 
corridor to her partner, Bob, and gets him to measure the spin 
projection in the same direction. If the two particles are independent, 
then both measurements give 50/50 chances for up/down. After Alice 
measures her particle, she splits into Alice_up and Alice _down 
according to her result. Both copies then go to Bob's laboratory, which 
by then has also split according to Alice's result. So Alice_up meets 
Bob, but when he measures his particle, he still has 50/50 chances of 
either result. Unfortunately, the only result that is consistent with 
spin conservation is that if Alice got 'up', he must get 'down', and 
vice verse (remember that the measurements are aligned by design).


Since Alice_up can't meet a Bob_up, there must be a non-local influence 
that determines Bob's result according to which Alice he meets. This is 
not removed be assuming no collapse and many worlds.


Of course, with time-like separation, the results can be explained by a 
local hidden variable, but no such explanation is available for 
space-like separated measurements, and the same explanation must be 
available for both cases. Since non-locality is still present for 
time-like separations, it must be present in all cases. So many worlds 
do not eliminate non-locality in Bell-pair measurements.


Bruce

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Re: Consistency of Postulates of QM

[agrayson2000]

On Saturday, November 11, 2017 at 10:34:13 AM UTC-7, John Clark wrote:
>
> On Fri, Nov 10, 2017 at 7:08 PM, Alan Grayson  > wrote:
>
> ​
>>> ​>> ​
>>> That's not the measurement problem, its determining if how and why 
>>> observation effects things. ​
>>>
>>
>> ​> ​
>> Not to split hairs, but why we get what we get in quantum measurements, 
>> and how measurement outcomes come to be what they are, are the same problem 
>> IMO.  
>>
>
> The measurement problem is not the ability or inability to predict exact 
> outcomes,
> ​ ​
> the measurement problem is defining what is
> ​ ​
> and
> ​ ​
> what
> ​ ​
> is not a measurement and
> ​ ​
> finding the
> ​ ​
> minimum properties a system
> ​ ​
> must
> ​ ​
> have to be an observer. Nondeterminism is not a problem and there is no 
> inconsistency at all regardless of what turns out to be true
> ​;​
> if some effects have no cause and true randomness exists then that's just 
> the way things are are
> ​ ​
> and
> ​ ​t
> here is no resulting paradox and no question that needs answering.
>
> ​
> The title of this thread is about the consistency of Quantum Mechanics, 
> but far more important than QM is the ability of ANY theory to be 
> compatible with experimental results, and one of those experiments shows 
> the violation of Bell's Inequality. And that violation tells us that for 
> ANY theory to be successful at explaining how the world works AT LEAST one 
> of the following properties of that theory must be untrue:
>
> 1) Determinism
> 2) Locality   
> 3) Realism
>
> Is Many Worlds deterministic? Yes in the sense that it just follows the 
> wave function and that is deterministic, it's only the collapse of the wave 
> function that is nondeterministic and that never happens in Manny Worlds.
>
> Is Many Worlds Local? Some say yes but I would say no because those other 
> worlds are about as non-local as you can get, you can't get there even with 
> infinite time on your side. But even if I'm wrong about locality Many 
> Worlds would still be in the running for a successful theory because it is 
> certainly not realistic.  
>
> John K Clark 
>

Why not just assume the wf collapses by an as-yet unknown process? Then, 
unlike MWI, you have a theory within the realm of testable physics and no 
need to explain where the energy comes from to create those other worlds -- 
uncountable in a simply slit experiment -- or what part of another world 
needs to be created to do these other worldly measurements? Is collapse so 
repugnant  (how so?) that one has to grasp at a cure that ostensibly is 
hugely worse than the alleged disease? Inquiring minds want to know. AG

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Re: Consistency of Postulates of QM

[John Clark]

On Fri, Nov 10, 2017 at 7:08 PM, Alan Grayson 
wrote:

​
>> ​>> ​
>> That's not the measurement problem, its determining if how and why
>> observation effects things. ​
>>
>
> ​> ​
> Not to split hairs, but why we get what we get in quantum measurements,
> and how measurement outcomes come to be what they are, are the same problem
> IMO.
>

The measurement problem is not the ability or inability to predict exact
outcomes,
​ ​
the measurement problem is defining what is
​ ​
and
​ ​
what
​ ​
is not a measurement and
​ ​
finding the
​ ​
minimum properties a system
​ ​
must
​ ​
have to be an observer. Nondeterminism is not a problem and there is no
inconsistency at all regardless of what turns out to be true
​;​
if some effects have no cause and true randomness exists then that's just
the way things are are
​ ​
and
​ ​t
here is no resulting paradox and no question that needs answering.

​
The title of this thread is about the consistency of Quantum Mechanics, but
far more important than QM is the ability of ANY theory to be compatible
with experimental results, and one of those experiments shows the violation
of Bell's Inequality. And that violation tells us that for ANY theory to be
successful at explaining how the world works AT LEAST one of the following
properties of that theory must be untrue:

1) Determinism
2) Locality
3) Realism

Is Many Worlds deterministic? Yes in the sense that it just follows the
wave function and that is deterministic, it's only the collapse of the wave
function that is nondeterministic and that never happens in Manny Worlds.

Is Many Worlds Local? Some say yes but I would say no because those other
worlds are about as non-local as you can get, you can't get there even with
infinite time on your side. But even if I'm wrong about locality Many
Worlds would still be in the running for a successful theory because it is
certainly not realistic.

John K Clark

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Re: Consistency of Postulates of QM

[Alan Grayson]

On Fri, Nov 10, 2017 at 12:46 PM, John Clark  wrote:

> On Thu, Nov 9, 2017 at 10:43 AM,  wrote:
>
> ​> ​
>> If the measurement problem were solved in the sense being able to predict
>> exact outcomes,
>>
>
> ​That's not the measurement problem, its determining if how and why
> observation effects things. ​
>

Not to split hairs, but why we get what we get in quantum measurements, and
how measurement outcomes come to be what they are, are the same problem
IMO.

>
> ​> ​
>> thus making QM a deterministic theory, would that imply an INCONSISTENCY
>> in the postulates of QM?
>>
>
> ​It's not just Quantum Mechanics, Bell proved that any theory that is
> deterministic must ​be nonlocal or non realistic or both, otherwise it
> would be inconsistent with experimental results.
>
>  John K Clark
>
>
>
>
>
>
>
>
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Re: Consistency of Postulates of QM

[John Clark]

On Thu, Nov 9, 2017 at 10:43 AM,  wrote:

​> ​
> If the measurement problem were solved in the sense being able to predict
> exact outcomes,
>

​That's not the measurement problem, its determining if how and why
observation effects things. ​

​> ​
> thus making QM a deterministic theory, would that imply an INCONSISTENCY
> in the postulates of QM?
>

​It's not just Quantum Mechanics, Bell proved that any theory that is
deterministic must ​be nonlocal or non realistic or both, otherwise it
would be inconsistent with experimental results.

 John K Clark

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Re: Consistency of Postulates of QM

[Bruno Marchal]

On 09 Nov 2017, at 16:43, agrayson2...@gmail.com wrote:

If the measurement problem were solved in the sense being able to  
predict exact outcomes,


?

Quantum Mechanics would be refuted (with or without wave packet  
reduction).





thus making QM a deterministic theory,


You mean QM+collapse. With QM-without-collapse: QM is determinist in  
the third person picture, and non determinist from the perspective of  
the most observers.






would that imply an INCONSISTENCY in the postulates of QM? TIA.


Yes. If QM with collapse becomes deterministic, I think this would be  
close to adding local hidden variable, which are refuted by EPR/Bell.


Ah, I see Brent wrote

It would make it possible to use EPR like experiments to send  
signals faster than light...which is to say backward in time.  That  
would pretty much screw up all known physics...and common sense.


Yes, I agree. QM+collapse+SP would be close to nonsense.

I agree with all what brent say, so I don't need to add anything. The  
measurement problem is quasi conceptually solved by decoherence in QM  
without collapse, although not entirely when we take into account  
Mechanism !
But the measurement problem is a "physical problem" if you assume the  
wave packet reduction, and the problem consists in making sense of it,  
in a way having testable consequence, and an as clear as possible  
interpretation of the wave(s) or the (density) matrix. It is not a  
problem for the applications. Measurement is indeed a powerful gate in  
quantum computing. The measurement problem is mainly the  
interpretation problem of the wave/matrix, to make sense of a notion  
of "physical reality".


It is also a good introduction of the mind body problem. Digital  
Mechanism generalizes it to arithmetic, and where the wave/matrix  
itself has to be justified from the reality about the numbers semi- 
computable relations verified in Arithmetic.


Bruno




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http://iridia.ulb.ac.be/~marchal/



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Re: Consistency of Postulates of QM

[Brent Meeker]

Already, people like Omnes regard it as a non-problem because 
decoherence diagonalizes the density matrix FAPP and so it can be 
interpreted as being the same as a mixed state, which is how classical 
probability is represented in QM.  But others say FAPP isn't good enough 
because (1) in principle it's reversible and (2) it doesn't answer the 
problem of the Heisenberg cut.  I think everyone agrees that if, within 
QM, it can be shown that the density matrix is strictly diagonalized by 
known dynamics - then that solves the measurement problem.


Brent

On 11/9/2017 6:13 PM, Alan Grayson wrote:
How would you define "the measurement problem" to conclude that 
strictly diagonalizing the density matrix would be a solution? TIA


On Thu, Nov 9, 2017 at 2:45 PM, Brent Meeker > wrote:


The "measurement problem" isn't necessarily finding a
deterministic subquantum dynamics.  If you could show that the
density matrix becomes strictly diagonal in some non-arbitrary way
(i.e. described by dynamics) and the eigenvalues obey the Born
rule (which I think would follow from Gleason's theorem) then I
think that would be a satisfactory solution.  And in fact I think
Zurek has provided most of that except for the details of the
dynamic description.  He relies on decoherence which produces
multiple copies of the measurement result in the environment and
he argues that the density matrix must be strictly diagonal in
order that repeating a measurement yields a repeat of the result. 
Given that much then you can either suppose this defines the
splitting into multiple worlds OR, following Omnes, you can say
the theory predicts probabilities and one of them is
realized...which is all you can expect of a probabilistic theory.

Brent

On 11/9/2017 12:01 PM, agrayson2...@gmail.com
 wrote:

If what you state is correct, then there's no solution to the
measurement problem (if that means discovering a deterministic
outcome for individual trials). Why then is the "measurement
problem" still considered a problem to be solved? What you've
presented is more or less proof that no such solution exists.

On Thursday, November 9, 2017 at 11:27:26 AM UTC-7, Brent wrote:

It would make it possible to use EPR like experiments to send
signals faster than light...which is to say backward in
time.  That would pretty much screw up all known
physics...and common sense.

Brent

On 11/9/2017 7:43 AM, agrays...@gmail.com wrote:

If the measurement problem were solved in the sense being
able to predict exact outcomes, thus making QM a
deterministic theory, would that imply an INCONSISTENCY in
the postulates of QM? TIA.
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Re: Consistency of Postulates of QM

[Alan Grayson]

How would you define "the measurement problem" to conclude that strictly
diagonalizing the density matrix would be a solution? TIA

On Thu, Nov 9, 2017 at 2:45 PM, Brent Meeker  wrote:

> The "measurement problem" isn't necessarily finding a deterministic
> subquantum dynamics.  If you could show that the density matrix becomes
> strictly diagonal in some non-arbitrary way (i.e. described by dynamics)
> and the eigenvalues obey the Born rule (which I think would follow from
> Gleason's theorem) then I think that would be a satisfactory solution.  And
> in fact I think Zurek has provided most of that except for the details of
> the dynamic description.  He relies on decoherence which produces multiple
> copies of the measurement result in the environment and he argues that the
> density matrix must be strictly diagonal in order that repeating a
> measurement yields a repeat of the result.  Given that much then you can
> either suppose this defines the splitting into multiple worlds OR,
> following Omnes, you can say the theory predicts probabilities and one of
> them is realized...which is all you can expect of a probabilistic theory.
>
> Brent
>
> On 11/9/2017 12:01 PM, agrayson2...@gmail.com wrote:
>
> If what you state is correct, then there's no solution to the measurement
> problem (if that means discovering a deterministic outcome for individual
> trials). Why then is the "measurement problem" still considered a problem
> to be solved? What you've presented is more or less proof that no such
> solution exists.
>
> On Thursday, November 9, 2017 at 11:27:26 AM UTC-7, Brent wrote:
>>
>> It would make it possible to use EPR like experiments to send signals
>> faster than light...which is to say backward in time.  That would pretty
>> much screw up all known physics...and common sense.
>>
>> Brent
>>
>> On 11/9/2017 7:43 AM, agrays...@gmail.com wrote:
>>
>> If the measurement problem were solved in the sense being able to predict
>> exact outcomes, thus making QM a deterministic theory, would that imply an
>> INCONSISTENCY in the postulates of QM? TIA.
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Re: Consistency of Postulates of QM

[Brent Meeker]

The "measurement problem" isn't necessarily finding a deterministic 
subquantum dynamics.  If you could show that the density matrix becomes 
strictly diagonal in some non-arbitrary way (i.e. described by dynamics) 
and the eigenvalues obey the Born rule (which I think would follow from 
Gleason's theorem) then I think that would be a satisfactory solution.  
And in fact I think Zurek has provided most of that except for the 
details of the dynamic description.  He relies on decoherence which 
produces multiple copies of the measurement result in the environment 
and he argues that the density matrix must be strictly diagonal in order 
that repeating a measurement yields a repeat of the result.  Given that 
much then you can either suppose this defines the splitting into 
multiple worlds OR, following Omnes, you can say the theory predicts 
probabilities and one of them is realized...which is all you can expect 
of a probabilistic theory.


Brent

On 11/9/2017 12:01 PM, agrayson2...@gmail.com wrote:
If what you state is correct, then there's no solution to the 
measurement problem (if that means discovering a deterministic outcome 
for individual trials). Why then is the "measurement problem" still 
considered a problem to be solved? What you've presented is more or 
less proof that no such solution exists.


On Thursday, November 9, 2017 at 11:27:26 AM UTC-7, Brent wrote:

It would make it possible to use EPR like experiments to send
signals faster than light...which is to say backward in time. 
That would pretty much screw up all known physics...and common sense.

Brent

On 11/9/2017 7:43 AM, agrays...@gmail.com  wrote:

If the measurement problem were solved in the sense being able to
predict exact outcomes, thus making QM a deterministic theory,
would that imply an INCONSISTENCY in the postulates of QM? TIA.
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Re: Consistency of Postulates of QM

[agrayson2000]

If what you state is correct, then there's no solution to the measurement 
problem (if that means discovering a deterministic outcome for individual 
trials). Why then is the "measurement problem" still considered a problem 
to be solved? What you've presented is more or less proof that no such 
solution exists. 

On Thursday, November 9, 2017 at 11:27:26 AM UTC-7, Brent wrote:
>
> It would make it possible to use EPR like experiments to send signals 
> faster than light...which is to say backward in time.  That would pretty 
> much screw up all known physics...and common sense.
>
> Brent
>
> On 11/9/2017 7:43 AM, agrays...@gmail.com  wrote:
>
> If the measurement problem were solved in the sense being able to predict 
> exact outcomes, thus making QM a deterministic theory, would that imply an 
> INCONSISTENCY in the postulates of QM? TIA.
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> You received this message because you are subscribed to the Google Groups 
> "Everything List" group.
> To unsubscribe from this group and stop receiving emails from it, send an 
> email to everything-li...@googlegroups.com .
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>
>
>

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Re: Consistency of Postulates of QM

[Brent Meeker]

It would make it possible to use EPR like experiments to send signals 
faster than light...which is to say backward in time.  That would pretty 
much screw up all known physics...and common sense.


Brent

On 11/9/2017 7:43 AM, agrayson2...@gmail.com wrote:
If the measurement problem were solved in the sense being able to 
predict exact outcomes, thus making QM a deterministic theory, would 
that imply an INCONSISTENCY in the postulates of QM? TIA.

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Consistency of Postulates of QM

[agrayson2000]

If the measurement problem were solved in the sense being able to predict 
exact outcomes, thus making QM a deterministic theory, would that imply an 
INCONSISTENCY in the postulates of QM? TIA.

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