Tuesday, March 14, 2023

Alain Connes: Music as noncommutative nonlocal Inner Automorphisms as the origin of thermodynamic asymmetric time

 Alain Connes - Temps et aléa du quantique Apr 14, 2015

If you take very seriously that the origin of variability doesn't come from the passing of time but comes simply from the formalism of quantum mechanics, from the Hilbert Space. Then it's absolutely vital that you can relate to ordinary time and time evolution as we know. What I'm saying is...this solution depends on the fact that you have a subsystem, it depends on the factorization... [noncommutative]....

You need to understand intuitively...this is the most difficult to explain...that this time evolution is UNavoidable....You can not suppress it... It's not an inner automorphism. It has the amazing property....it's in the center of the group of inner automorphisms. Any other automorphisms of the algebra will commute with it. It's canonical. It doesn't depend on any choice. ...

You take a system that you repeat... it repeats everywhere ...to infinity...it's repetition that allows you to see time evolution...it's the factorizations which are infinite repetitions that give you this time evolution... Otherwise you wouldn't see it. ...Hilbert space and Hilbert Space operators KNOW and know a lot more than we think....the passing of time is due to our partial knowledge, because we don't know the full system....

What are the observables for gravitation? Who can we say where we are? The answer is spectral [frequency]. ...It's not enough to know the spectral operators... ...Two noncommutative shapes that are Isospectral [i.e. both Perfect Fifth]...They have the same spectrum but they do not have the same second invariant. [Second-order tensors may be described in terms of shape and orientation.]

You find three types of notes of the spectrum. Integers plus 1/4 [Perfect Fourth], Integers plus 1/2 [Perfect Fifth] and Integers in the square of the spectrum [Octave] there are three kinds of NOTES. When you look at the possible chords - this is like the piano in which you can play...because they are three kinds of notes. The chords of two notes are possible for some shapes [Perfect Fifth] but not other shapes [Perfect Fourth]. The point is spectral, given by correlations between the eigenvalues (frequencies) of the Dirac operator.

There are factorizations with infinite degrees of freedom, that they generate, their own time; and this is a partial knowledge and of course it's related to thermodynamics and temperature and all that. ...The time evolution would not be the same if you changed T to Minus T. If it were the same when you changed T to Minus T then it would be trivial.

 What I want is to transmit a mathematical fact...it's extremely striking. It suggests a philosophical fact ...which is that the fundamental variability is quantum other than the passing of time.

It's unique up to inner automorphisms; it means you have the flexibility to change it locally. So you can be locally out of equilibrium. You can have a pure density matrix which on the subalgebra in the factorization you see something which is not pure of course. Factor 4 x 4 matrices as 2 x 2 matrix times 2 x 2 matrix. Now take a vector, pure in four dimensional Hilbert Space... And then you do the inner transfer product of the four dimensional Hilbert space. ...That will be a factorization of Type III. ...A corresponding vector and you just repeat it. That's enough to get the time evolution....The time evolution is in the Subparts, it's not in the full thing.

By the way, I should say, of course this was the motivation for why I spent many years studying noncommutative geometry...

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