I think physics fundamentally constrains causal rules to obey the
Church-Turing thesis. That is, computable dynamics are computable on a
Turing machine. However, there is some form of axiomatic incompleteness
such as Gödel's theorem or Turing's result on universal Turing machines. We
have then
Exactly. That's why I wrote "...our part of universe". Whether the
part of the system that we can never interact with is relevant is a
question for metaphysics.
Brent
On 8/28/2022 11:58 AM, smitra wrote:
But then you are describing only part of the system using QM. The
whole system
But then you are describing only part of the system using QM. The whole
system includes the universe itself, this is described by a
wavefunctional that assigns amplitudes to entire space-time
configurations and the fields in it.
Saibal
On 28-08-2022 20:42, Brent Meeker wrote:
But in the
But in the mean time the expansion of the universe has moved lots of
what the wave function of the universe beyond our horizon. And what we
can access is not the unitary evolution of what we could earlier.
Brent
On 8/28/2022 1:34 AM, smitra wrote:
It's a unitary map, it will evolve the past
It's a unitary map, it will evolve the past state into a superposition
of many different states. One may argue that this is meaningless, as one
has to choose a basis. But this is essentially what time evolution
operator does for you. If you work in a particular basis then applying
the time
Works for me, and may not work for Thee!
[2104.03902] The Autodidactic Universe (arxiv.org)
-Original Message-
From: Lawrence Crowell
To: Everything List
Sent: Fri, Aug 26, 2022 7:57 pm
Subject: Re: Information conservation and irreversibility
On Friday, August 26, 2022 at 4
Why do you think the evolution is deterministic of our part of universe?
Brent
On 8/27/2022 9:17 AM, smitra wrote:
The time evolution operator maps past states of our universe to
present states. So, the present state of the universe, which includes
our conscious experience of the present
The time evolution operator maps past states of our universe to present
states. So, the present state of the universe, which includes our
conscious experience of the present state was also present in the early
universe in a nonlocal way where there would be no obvious sign of us
existing at
Even if it were sentient its thoughts would be incomprehensible to us.
Brent
On 8/26/2022 2:52 AM, John Clark wrote:
On Fri, Aug 26, 2022 at 5:41 AM Lawrence Crowell
wrote:
/> I do not think much of this idea that the universe is sentient./
I think the idea is a bit silly becauseI
On Friday, August 26, 2022 at 4:53:15 AM UTC-5 johnk...@gmail.com wrote:
> On Fri, Aug 26, 2022 at 5:41 AM Lawrence Crowell
> wrote:
>
> *> I do not think much of this idea that the universe is sentient.*
>
>
> I think the idea is a bit silly because I don't see any way to prove or
> disprove
Or not? Mayve.
-Original Message-
From: John Clark
To: everything-list@googlegroups.com
Sent: Fri, Aug 26, 2022 5:52 am
Subject: Re: Information conservation and irreversibility
On Fri, Aug 26, 2022 at 5:41 AM Lawrence Crowell
wrote:
> I do not think much of this idea
the doyens of
physics and mathematics. I never thought it would thrill you or Dr. Sabine for
that matter.
-Original Message-
From: Lawrence Crowell
To: Everything List
Sent: Fri, Aug 26, 2022 5:41 am
Subject: Re: Information conservation and irreversibility
I do not think much
On Fri, Aug 26, 2022 at 5:41 AM Lawrence Crowell <
goldenfieldquaterni...@gmail.com> wrote:
*> I do not think much of this idea that the universe is sentient.*
I think the idea is a bit silly because I don't see any way to prove or
disprove it even in theory. And in the entire universe the only
knowledge base.
>
> https://time.com/6208174/maybe-the-universe-thinks/
>
>
> -Original Message-
> From: Lawrence Crowell
> To: Everything List
> Sent: Mon, Aug 22, 2022 6:34 am
> Subject: Re: Information conservation and irreversibility
>
> On Sunday,
22, 2022 6:34 am
Subject: Re: Information conservation and irreversibility
On Sunday, August 21, 2022 at 2:03:41 PM UTC-5 meeke...@gmail.com wrote:
On 8/21/2022 4:22 AM, Lawrence Crowell wrote:
On Friday, August 5, 2022 at 6:14:42 PM UTC-5 Bruce wrote:
On Sat, Aug 6, 2022 at 7:54 AM
On Sunday, August 21, 2022 at 2:03:41 PM UTC-5 meeke...@gmail.com wrote:
>
>
> On 8/21/2022 4:22 AM, Lawrence Crowell wrote:
>
> On Friday, August 5, 2022 at 6:14:42 PM UTC-5 Bruce wrote:
>
>> On Sat, Aug 6, 2022 at 7:54 AM Jesse Mazer wrote:
>>
>>> Why do you say it's irreversible in principle?
On 8/21/2022 4:22 AM, Lawrence Crowell wrote:
On Friday, August 5, 2022 at 6:14:42 PM UTC-5 Bruce wrote:
On Sat, Aug 6, 2022 at 7:54 AM Jesse Mazer wrote:
Why do you say it's irreversible in principle? Wouldn't the
time-reverse of that just be a photon traveling towards
On Sun, Aug 21, 2022 at 7:23 AM Lawrence Crowell <
goldenfieldquaterni...@gmail.com> wrote:
*> The same happens with quantum mechanics. There is a Poincare recurrence,
> given by the exponential of the Euclideanized action. However, there is an
> additional phase, which defines the quantum
On Friday, August 5, 2022 at 6:14:42 PM UTC-5 Bruce wrote:
> On Sat, Aug 6, 2022 at 7:54 AM Jesse Mazer wrote:
>
>> Why do you say it's irreversible in principle? Wouldn't the time-reverse
>> of that just be a photon traveling towards an atom and being absorbed,
>> which is permitted by the
It's puzzling why Bruce and Clark affirm IR-reversible in principle in the
context of the collapse model of the CI, when they should know that this is
the source of the error. If the apparatus is treated quantum mechanically,
we are left SOLELY with IR-reversible FAPP. But this is still an
I was referring to IRREVERSIBLIY IN PRINCIPLE, which is an artifact of the
collapse hypothesis of the CI. What remains, for sure, is IRREVERSIBILITY
FAPP. AG
On Saturday, August 13, 2022 at 9:07:04 AM UTC-6 Alan Grayson wrote:
> IRREVERSIBILITY is an artifact of the CI, where collapse occurs
IRREVERSIBILITY is an artifact of the CI, where collapse occurs to an
eigenstate of the observable being measured. But if the measuring apparatus
is treated quantum mechanically, all processes associated with measurements
are unitary and reversible.
On Saturday, August 13, 2022 at 12:47:06 AM
That's defining IRREVERSIBLE FAPP. OTOH, if X and Y produce Z at any time,
I don't see any way to reverse the process, so it's IRREVERSIBLE IN
PRINCIPLE. Do you agree? AG
On Saturday, August 6, 2022 at 5:02:17 AM UTC-6 johnk...@gmail.com wrote:
> On Fri, Aug 5, 2022 at 6:47 PM Jesse Mazer
What you're leaving out is that there are boundary conditions that are
impossible to realize, not just because they are too complex, like a
high entropy state, but because they require infinite specifications.
Brent
On 8/6/2022 6:25 AM, Jesse Mazer wrote:
Physicists may distinguish between
On 8/6/2022 5:16 AM, Jesse Mazer wrote:
The question of whether a process happening to particular bits of
matter can be reversed in those same bits of matter may be an
interesting one worth thinking about, but I think it creates
unnecessary confusion to use the term "reversibility" to talk
Physicists may distinguish between time-reversibility of the dynamics, also
called "microscopic reversibility" at
https://en.wikipedia.org/wiki/Microscopic_reversibility , vs. "macroscopic"
or "thermodynamic" irreversibility, which as you say is ultimately thought
to be a statistical consequence
The question of whether a process happening to particular bits of matter
can be reversed in those same bits of matter may be an interesting one
worth thinking about, but I think it creates unnecessary confusion to use
the term "reversibility" to talk about this, since that isn't what
physicists
On Fri, Aug 5, 2022 at 6:47 PM Jesse Mazer wrote:
*> But when physicists say that a given system's dynamics are "reversible"
> doesn't this generally involve an appeal to different initial boundary
> conditions?*
>
If at the time of the Big Bang the universe was it in an extremely low
entropy
Can't your argument be extended to the question of whether time is
irreversible FAPP, or IRREVERSIBLE IN PRINCIPLE. For example, consider a
gas at some temperature in an enclosure which is cooling. We might conclude
the time is irreversible FAPP, but quantum theory does not give any
On Sat, Aug 6, 2022 at 12:10 PM Jesse Mazer wrote:
> Are you defining "process" as a *pattern* of behavior which can be
> duplicated with different bits of matter, or as something that refers to
> some specific bits of matter, so that reversing a process would require
> doing it to the same bits
Are you defining "process" as a *pattern* of behavior which can be
duplicated with different bits of matter, or as something that refers to
some specific bits of matter, so that reversing a process would require
doing it to the same bits of matter that underwent the original process? I
think if a
But reversibility as understood by physicists isn't about whether you could
"create" the appropriate type of system with advanced technology or
whatever, it's about the abstract question of whether the time-reversed
version is a valid solution to the same dynamical laws of physics. One
could
I'm pointing out that in some cases creating the reverse boundary
conditions is impossible in principle because they are at infinity.
Brent
On 8/5/2022 3:47 PM, Jesse Mazer wrote:
But when physicists say that a given system's dynamics are
"reversible" doesn't this generally involve an appeal
On Sat, Aug 6, 2022 at 9:29 AM Jesse Mazer wrote:
> "The time invariance of the laws means that a photon coming in from outer
> space is consistent with the laws. But that cannot be the same photon."
>
> But "reversibility" as physicists define it has nothing to do with
> actually causing the
"The time invariance of the laws means that a photon coming in from outer
space is consistent with the laws. But that cannot be the same photon."
But "reversibility" as physicists define it has nothing to do with actually
causing the same system to reverse itself, it's a more abstract notion that
On Sat, Aug 6, 2022 at 7:54 AM Jesse Mazer wrote:
> Why do you say it's irreversible in principle? Wouldn't the time-reverse
> of that just be a photon traveling towards an atom and being absorbed,
> which is permitted by the laws of physics given a different set of initial
> boundary
But when physicists say that a given system's dynamics are "reversible"
doesn't this generally involve an appeal to different initial boundary
conditions? (The end conditions with all the velocities reversed and
treated as a new system's initial conditions, for example.) Are you using
That's why I wrote, "The arrow of time comes from the boundary condition."
Brent
On 8/5/2022 2:54 PM, Jesse Mazer wrote:
Why do you say it's irreversible in principle? Wouldn't the
time-reverse of that just be a photon traveling towards an atom and
being absorbed, which is permitted by the
Why do you say it's irreversible in principle? Wouldn't the time-reverse of
that just be a photon traveling towards an atom and being absorbed, which
is permitted by the laws of physics given a different set of initial
boundary conditions?
On Thu, Aug 4, 2022 at 5:10 PM Brent Meeker wrote:
> If
What do the physicists and engineers on the list think of Zurek's idea the
quantum measurements become irreversible, in principle, once a record of
the quantum measurement is made?
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5990664/#RSTA20170315C9
Dirk
On Thursday, August 4, 2022 at
So what's the bottom line; are physical processes reversible or not? Does
the answer depend on whether the universe is infinite, that is, without a
boundary condition, or not? TY. AG
On Thursday, August 4, 2022 at 3:10:47 PM UTC-6 meeke...@gmail.com wrote:
> If a photon is emitted into an
am
Subject: Re: Information conservation and irreversibility
I meant to write that information conservation depends on reversibility! How
solid is that assumption? AG
On Thursday, August 4, 2022 at 1:31:31 AM UTC-6 Alan Grayson wrote:
I assume information conservation depends on irreversibility
If a photon is emitted into an infinite universe it is irreversible in
principle, not just FAPP. But it doesn't mean the physical theory is
irreversible. The arrow of time comes from the boundary condition.
Brent
On 8/4/2022 8:47 AM, smitra wrote:
On 04-08-2022 17:41, Alan Grayson wrote:
On Thu, Aug 4, 2022 at 11:47 AM smitra wrote:
On 04-08-2022 17:41, Alan Grayson wrote:
>> I *recall Bruce giving an example of an irreversible process, but I **can't
>> recall the details. AG*
>
>
> *> Probably a FAPP irreversible process.*
>
If states X and Y can both produce Z then it's
On 04-08-2022 17:41, Alan Grayson wrote:
I recall Bruce giving an example of an irreversible process, but I
can't recall the details. AG
Probably a FAPP irreversible process.
Saibal
On Thursday, August 4, 2022 at 6:39:04 AM UTC-6 Jason wrote:
On Thu, Aug 4, 2022, 5:23 AM Alan Grayson
I recall Bruce giving an example of an irreversible process, but I can't
recall the details. AG
On Thursday, August 4, 2022 at 6:39:04 AM UTC-6 Jason wrote:
> On Thu, Aug 4, 2022, 5:23 AM Alan Grayson wrote:
> > I meant to write that information conservation depends on reversibility!
> How
On Thu, Aug 4, 2022, 5:23 AM Alan Grayson wrote:
> I meant to write that information conservation depends on reversibility!
How solid is that assumption? AG
I think it is pretty good.
I think reversibility is part of it. Certainly in a reversable Newtonian
kind of physics (no GR and no QM,
I meant to write that information conservation depends on *reversibility! *How
solid is that assumption? AG
On Thursday, August 4, 2022 at 1:31:31 AM UTC-6 Alan Grayson wrote:
> I assume information conservation depends on irreversibility. How solid is
> the latter assumption? AG
-
I assume information conservation depends on irreversibility. How solid is
the latter assumption? AG
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