I do not think much of this idea that the universe is sentient. LC
On Thursday, August 25, 2022 at 8:53:01 PM UTC-5 spudb...@aol.com wrote: > Ah, LC, your colleague Sabine Hossenfelder has given forth on the > autodidactic universe. She doesn't hold with it but still enriches the > knowledge base. > > https://time.com/6208174/maybe-the-universe-thinks/ > > > -----Original Message----- > From: Lawrence Crowell <goldenfield...@gmail.com> > To: Everything List <everyth...@googlegroups.com> > Sent: Mon, Aug 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 Jesse Mazer <laser...@gmail.com> 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 conditions? > > > The laws of physics are invariant under the time-reversal operation. That > does not imply that irreversible processes are impossible. Brent has > pointed out that sending a photon out into an expanding universe is a > process that is irreversible in principle. 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. The idea that you can surround > everything with a perfectly reflecting mirror, so that all emitted photons > are returned, is just a fanciful diversionary tactic -- no such > reflective surrounds exist. Besides, reflecting photons back is not a > process reversal in an expanding universe. The red shift induced by the > expansion means that the returning photon inevitably has lower energy than > the emitted photon. > > Bruce > > > It is the case of a billiard ball impacting another vs a set of racked > billiard balls. If I were to take a video of a billiard ball impacting > another, framed this in the center of mass of the balls and mask any > perception of the rotation of the balls, the video run backwards and > forwards would by very similar. There would be nothing to distinguish the > forwards and backwards video. It is perfectly time reverse invariant. Now > consider the racked balls impacted by the cue-ball. It is pretty easy to > see which is forwards in time, as we do not expect balls to rush inwards > and align themselves in an ordered set and eject another. However, if the > table were "perfect," it had frictionless surface and the balls reflected > off the sides perfectly, if we wait long enough it will return to its > original state. This is Poincare recurrence. You have to wait a lot longer > than the duration of the universe so far. > > 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 complexity and the recurrence > time on that is the exponential of the Poincare recurrence time. > > > Is that in some thermodynamic limit? There is no chaos in QM so I would > expect the recurrence time to be bounded by that. Do you have a reference? > > Brent > > > Look up Susskind arXiv:1810.11563v1 [hep-th] 27 Oct 2018 . > > LC > > > > Quantum complexity is interesting, and I think it involves the > Hilbert-Polya conjecture concerning the Riemann zeta function and the zeros > being mapped to the eigenvalues of a Hermitian operator. In this case the > recurrence is a vast period of time, as long as the stability of the de > Sitter manifold of the cosmos. > > In effect we have limitations on what we can observe and account for, but > ultimately the universe may have an accounting of quantum information, at > least for unitary systems and quantum gravitation with Petrov types that > have Killing vectors. When it comes to the universe at large, that may be a > different matter. Such ideas may turn out to be false. > > LC > > > -- > 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. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/everything-list/f2cf6a7e-a90f-4f22-9f88-84bf08417581n%40googlegroups.com > > <https://groups.google.com/d/msgid/everything-list/f2cf6a7e-a90f-4f22-9f88-84bf08417581n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > > -- > 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. > To view this discussion on the web visit > > https://groups.google.com/d/msgid/everything-list/2e92f31f-9d08-4ed1-9d90-42c4dfd63ef2n%40googlegroups.com > > <https://groups.google.com/d/msgid/everything-list/2e92f31f-9d08-4ed1-9d90-42c4dfd63ef2n%40googlegroups.com?utm_medium=email&utm_source=footer> > > . > -- You received this message because you are subscribed to the Google Groups "Everything List" group. 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