On Monday, November 27, 2017 at 4:48:12 PM UTC, Bruno Marchal wrote:
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> On 24 Nov 2017, at 21:58, [email protected] <javascript:> wrote:
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> On Friday, November 24, 2017 at 12:15:46 PM UTC-7, Bruno Marchal wrote:
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>> On 22 Nov 2017, at 22:51, [email protected] wrote:
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>> On Wednesday, November 22, 2017 at 5:24:48 PM UTC, Bruno Marchal wrote:
>>>
>>>
>>> On 22 Nov 2017, at 09:55, [email protected] wrote:
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>>>
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>>> On Tuesday, November 21, 2017 at 12:43:05 PM UTC-7, Bruno Marchal wrote:
>>>>
>>>>
>>>> On 20 Nov 2017, at 20:40, [email protected] wrote:
>>>>
>>>>
>>>>
>>>> On Monday, November 20, 2017 at 6:56:52 AM UTC-7, Bruno Marchal wrote:
>>>>>
>>>>>
>>>>> On 18 Nov 2017, at 21:32, [email protected] wrote:
>>>>>
>>>>>
>>>>>
>>>>> On Saturday, November 18, 2017 at 1:17:25 PM UTC-7, Brent wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>> On 11/18/2017 8:58 AM, John Clark wrote:
>>>>>>
>>>>>> * > I think "must" is unwarranted, certainly in the case of the
>>>>>>> MWI. Rather, it ASSUMES all possible measurements must be realized in
>>>>>>> some
>>>>>>> world. **I see no reason for this assumption other than an
>>>>>>> insistence to fully reify the wf in order to avoid "collapse".*
>>>>>>>
>>>>>>
>>>>>> The MWI people don't have to assume anything because
>>>>>> there is absolutely nothing in t
>>>>>> he Schrodinger
>>>>>> Wave E
>>>>>> quation
>>>>>> about collapsing, its the Copenhagen people who have to assume that
>>>>>> somehow it does.
>>>>>>
>>>>>>
>>>>>> It's not just an assumption. It's an observation. The SE alone
>>>>>> didn't explain the observation, hence the additional ideas.
>>>>>>
>>>>>> Brent
>>>>>>
>>>>>
>>>>> *Moreover, MWI DOES make additional assumptions, as its name
>>>>> indicates, based on the assumption that all possible measurements MUST be
>>>>> measured, in this case in other worlds. *
>>>>>
>>>>>
>>>>> That is not an assumption. It is the quasi-literal reading of the
>>>>> waves. It is Copenhagen who added an assumption, basically the assumption
>>>>> that the wave does not apply to the observer: they assumed QM was wrong
>>>>> for
>>>>> the macroscopic world (Bohr) or for the conscious mind (Wigner, von
>>>>> Neumann) depending where you put the cut.
>>>>>
>>>>
>>>> *CMIIAW, but I see it, the postulates tell us the possible results of
>>>> measurements. They don't assert that every possible measurement will be
>>>> realized.*
>>>>
>>>> What do you mean by realize?
>>>>
>>>
>>> *Realized = Measured. AG*
>>>
>>>
>>>
>>> Measured by who?
>>>
>>
>> Doesn't this same question come up in MWI, and with Many Worlds the
>> problem seems to metastasize. AG
>>
>>
>>> More precisely, if Alice look at a particle is state up+down: the wave
>>> is A(up + down) = A up + A down. Then A looks at the particles. The waves
>>> evolves into A-saw-up up + A-saw-down down. Are you OK to say that a
>>> measurement has occurred? Copenhagen says that the measurement gives
>>> either A-saw-up up or A-saw-up down, but that NEVER occurs once we abandon
>>> the collapse. So without collapse, a measurement is a first person
>>> experience. In this case, it is arguably the same as the experience of
>>> being duplicated.
>>>
>>
>> If you could revise your reply using the wf of the singlet state (without
>> the normalizing factor) in the following form, I might be able to evaluate
>> your analysis; namely, ( |UP>|DN> - |DN>|UP> ). For example, I am not clear
>> how you apply linearly.Does each term in the sum represent a tensor
>> product? TIA AG
>>
>>
>> I was just explaining that a measurement is any memorable interaction,
>> which is simplest to illustrate with a tensor product of Alice (|A>)and a
>> simple superposition. In your notation: |A> (|UP> + |DN>) = |A> |UP> + |A>
>> |DN> .
>>
>
> *Before the measurement Alice is NOT entangled with the entangled pair
> since it is isolated; *
>
>
> Well, there is not entangled pair here. As I said, I was coming on the
> very basic: the linearity of the tensor product on superposition.
>
>
>
> *nor afterward since the system being measured is now NOT in a
> superposition of states. *
>
>
> Assuming a collapse, which I don't. Without collapse, you can never
> eliminate a superposition.
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>
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> * So your tensor addition is based on fallacies, *
>
>
> ? Be explicit, please.
>
When you write |A> (|UP> + |DN>) = |A> |UP> + |A> |DN> , on left side
you're assuming Alice is entangled with the entangled pair. But she is NOT
since the entangled pair is assumed to be isolated before the measurement.
AG
> Bruno
>
>
>
> *which I infer permeates your general analysis of this situation. BTW,
> please see my last post where I raised additional issues. TY, AG*
>
>>
>> In the case of the singlet state, it is more subtle, as |UP>|DN> -
>> |DN>|UP> describes a many-worlds with Alice having a spin in any direction,
>> and Bob, too but the opposite relatively to each others (the notation is
>> misleading). We must keep in mind the rotational invariance of the spin. So
>> we the Alice Bob situation is more intricate and tedious to describe.
>> Sometimes I referred to the simple account of this in the Everett FAQ by
>> Michael Clive Price, but it seems not available since some times. We have
>> copied the relevant details in previous discussions though, so you might
>> try to find it in the archives with the key word "Michael", or something. I
>> have unfortunately not the time "here and now". Later perhaps. With
>> Everett, it is important to reason independently of the bases in between
>> the measurements.
>>
>> I guess you see that violation of the BI leads to "action at a distance"
>> if we assume a collapse, or a mono-world theory. I don't see Bell'
>> argument applying in the MW context, though.
>>
>> Bruno
>>
>>
>>
>>
>>> Without collapse, the measurement are described by the quantum laws.
>>>>
>>>
>>> *That's precisely what QM doesn't describe, which constitutes part of
>>> the measurement problem. AG*
>>>
>>>
>>> Just see above. QM describes precisely why the observers believe
>>> correctly (with respect to their first person notion) having done
>>> measurement, and got precise outcomes, but from the 3p waves perspectives,
>>> all we have is a structured collection of relative states (which all exists
>>> and are structured in arithmetic, BTW).
>>>
>>>
>>>
>>>
>>> An observer along a superposition up + down, *is* the same state as the
>>>> observer along up superposed with the observer down, if he look in the {up
>>>> + down, up - down} basis, "he" will see he is in up+down, but if he looks
>>>> in the {up down} basis; the observer consciousness differentiate, in his
>>>> first person perspective, but the solution of the wave describes the two
>>>> outcomes realized from the point of view of each observer. You can't
>>>> decide
>>>> to make one of them into a zombie.
>>>>
>>>
>>> *I have no idea what you mean. Please try again. AG*
>>>
>>>
>>> The tensor product is linear, so A(up + down) = (A up) + (A down). OK?
>>>
>>> the evolution is linear and when A looks at the particle: she is
>>> described by (A-up up) + (A-down down). (with of course 1/sqrt(2)
>>> everywhere).
>>>
>>> the consciousness of A has differentiated into (A-up) and (A-down). With
>>> Bohr, one among A-up and A-down mysteriously disappears. With Bohm (one
>>> world + a potential simulating the entire Many-world, but "without
>>> particles") one among A-up and A-down becomes a zombie, even one lacking a
>>> body made of particles, yet, the waves describes them as being alive like
>>> you and me, and we can test it (in principle) by making quantum computation
>>> with oneself.
>>>
>>>
>>>
>>>
>>>
>>> *So I see an additional assumption in the MWI. AG*
>>>>
>>>> I disagree, and Everett would disagree. I am aware most people claims
>>>> Everett and Copenhagen are differet intepretations, but from a
>>>> metamathematical obvious view: Everett and Copenhagen are different
>>>> theories.
>>>>
>>>
>>> *They have identical postulates but Everett adds another non-trivial one
>>> as I indicated above; namely, that every possible measurement is realized,
>>> that is measured, in another world. I don't see why you insist on denying
>>> something so obvious. AG*
>>>
>>>
>>>
>>> ?
>>>
>>> I think you should read Everett. he propose a new formulation of QM, and
>>> it is copenhagen with the withdrawal of the collapse postulate.
>>>
>>> All measurement are realized in the sense that no superposition ever
>>> collapse, but that it looks in that way from the first person perspective
>>> of the observer. he reduces the quantum indeterminacy to the classical
>>> self-indetermination based on amoeba-like duplication. The only problem is
>>> that his task is not finished: by using mechanism (as he recognizes
>>> explicitly in his long text) he must take into account all computations,
>>> not just the quantum one. in other word, the wave itself must be recovered,
>>> and indeed the math indicates that is possible, as quantum logics appears
>>> at the place where such task must be handled.
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>> Everett is the SWE, and Copenhagen is SWE + collapse. We might accept
>>>> that Everett theory has not yet justify all aspects of what could be the
>>>> physical reality (and provably so if we assume digital mechanism in
>>>> cognitive science), but, to be short, it is less crazy than any theory
>>>> making the collapse into a physical phenomenon.
>>>>
>>>
>>> *Why crazy? What we seem to observe IS collapse;*
>>>
>>>
>>> yes. but that is the whole difference between a platonist and an
>>> aristotelian. The aristotelian define reality by what they see. The
>>> platonist define reality by whatever makes us to believe that we see
>>> something.
>>>
>>> And we do not observe a collapse/ We observe a cat, or something.
>>> Exactly like the wave without collapse, + a mechanist theory of mind,
>>> predicts.
>>>
>>> Everett just soleved the mind-body problem, at the conceptual level. And
>>> partially, because my contribution here is that this *has to be*
>>> prolongated in arithmetic, and the wave must be justified itself by a
>>> statistic on all computations. It works at the proposition level: it gives
>>> quantum logic at the place of propositional physics.
>>>
>>>
>>>
>>>
>>>
>>> * that is, all probabilities evolving to zero except the measured
>>> probability evolving to 1, by an as-yet unknown physical process. AG *
>>>
>>>
>>> A unknown physical phenomenon that Einstein criticized already in 1927,
>>> by showing that the collapse would need to be non covariant. The wave has
>>> to vanish instantaneously. With the many-worlds, there is no problem at all
>>> for the easy 1927 thought experience: the wave never vanishes, but you
>>> localize yourself on which branch you are in the superposition.
>>>
>>> The measurement problem exists only when we associate a unique outcome
>>> for the experiment. With Everett, measurement are explained by
>>> interaction+entanglement. decoherence then explains why we can't see the
>>> "other branches".
>>>
>>> I know that Bruce and Clark disagree, but in my opinion, Everett
>>> (non-collapse) solves all the conceptual problems that Einstein disliked so
>>> much in QM. We get a reversible deterministic local physical "big picture".
>>>
>>> Now, with mechanism, this leads to no universe at all, in the
>>> aristotelian sense of the words, as the "physical universe", the wavy
>>> multiverse of Everett-Deutsch, has to be itself the winner in a deeper game
>>> played by all computations (which exists in elementary arithmetic). "All
>>> computations" is a very solid notions, thanks to Gödel's theorem which
>>> protects Church's thesis and Mechanism from a vast collection of
>>> reductionist philosophy.
>>>
>>> Bruno
>>>
>>>
>>>
>>>
>>>
>>> *I reject this hypothesis. What I do concede is that in the case of the
>>>>> Multiverse of String Theory, if time is infinite and the possible
>>>>> universes
>>>>> finite -- 10^500 -- all possible universes will be, or have been,
>>>>> realized.
>>>>> AG*
>>>>>
>>>>>
>>>>> OK, but that is not Everett-Deustch "multiverse" (relative state,
>>>>> many-worlds, etc.).
>>>>>
>>>>
>>>> *Too much parsing! I was trying to explain that the Multiverse of
>>>> String Theory is manifestly *different* from the Many Worlds of the MWI.
>>>> AG *
>>>>
>>>>
>>>> Yes. you are right on this. In string theory with collapse (if this
>>>> could even make sense), you have 10^500 physical realities. In string
>>>> theory without collapse, you have (10^500 * Infinity) physical realities,
>>>> at first sight (with mechanism they are just "coherent dreams" (sigma_1
>>>> true sentences seen in the Bp & ~Bf mode) by Numbers).
>>>>
>>>> Bruno
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>> Bruno
>>>>>
>>>>
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>>>>
>>>> http://iridia.ulb.ac.be/~marchal/
>>>>
>>>>
>>>>
>>>>
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>>> http://iridia.ulb.ac.be/~marchal/
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>>>
>>>
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>> http://iridia.ulb.ac.be/~marchal/
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