Are all processes CPT symmetric like measurement, stimulated emission?

[Jarek 31]

TL;DR Summary

While CPT theorem says that CPT symmetry holds for all physical phenomena, for some processes such reversibility seems highly nonintuitive - starting with measurement ...

https://en.wikipedia.org/wiki/CPT_symmetry says "CPT theorem says that CPT symmetry holds for all physical phenomena" - e.g. we could imagine decomposition of given phenomena into Feynman diagrams and apply CPT symmetry to all of them.
However, for some o processes such reversibility seems highly nonintuitive - let us try to discuss them.

1) It is good to start with deexcitation as it seems there is no problem with it (?):
excited atom <-> deexcited atom + photon

2) Let us look at measurement, e.g. in Stern-Gerlach idealization, for example of spin - which seems changed during measurement, and corresponds to angular momentum - so shouldn't there be something more e.g. photon carrying this difference of angular momentum?
unmeasured spin <-> measured spin + something carrying difference of angular momentum (e.g. EM wave like photon)
Including such hypothetical artifact carrying difference of angular momentum, momentum, energy etc. allows to see measurement as CPT symmetric reversible process - explain asymmetry by difficulty of preparing the right hand side situation ...
But can we do it - does measurement always have such artifact? Could it be confirmed or disproved?

3) Synchrotron radiation in which electrons usually in strong external magetic field produce photons:
electron before synchrotron radiation <-> electron after + photon
It seems to require some internal change in this electron (?) - could it be rotation of its spin accordingly to magnetic field used to bend the trajectory (V = -mu B like in Zeeman effect)?

4) Stimulated emission in laser: causing absorption of such photon by target later.
So is there stimulated absorption e.g. in CPT analogue of laser: causing emission of such photon by target earlier?

5) State preparation of e.g. <0| qubit out of {<0|, <1|} requiring nonunitarity - can it have CPT symmetric analogue: enforcing e.g. |0> at the end of quantum algorithm? (it is done in postselection but it is cheating).

6) Big Bang - does the hypothetical initial point satisfy CPT symmetry? Doesn't this symmetry suggest Big Bounce instead?

So are all of them CPT symmetric, reversible?
Any other problematic phenomena? (... beside entropy growth)

 

[Vanadium 50]

When every other word is bolded this becomes very hard to read.

With six examples, it doesn't sound like you are asking questions so much as pushing a position. You might want to take a look at the PF Rules on this.

CPY symmetry is a statement that relates certain properties of particles and antiparticles (the C). It does not say that a broken vase must spontaneously reassemble or any of your six examples.

 

[Jarek 31]

I have started with statement from Wikipedia saying that this symmetry holds for all phenomena, and wanted to discuss here some problematic cases.
Especially measurement - which is often seen as irreversible phenomenon - so does it invalidate the CPT theorem?

 

[Vanadium 50]

Wikipedia is not an acceptable reference here.

 

[Jarek 31]

Wikipedia is kind of introductory reference, to get a glimpse without subjectively choosing references yourself, and it points to real references. If you disagree with this article, please improve it.
The original paper is Schwinger's https://journals.aps.org/pr/abstract/10.1103/PhysRev.82.914 - you can use it or some other references to support your view on the questions asked here.

 

[Vanadium 50]

Schwinger doesn't say any of that either.

Since it's clear that:
a. You misunderstand what CPT says, and
b. You are more interested in promoting your own flawed view than in gaining understanding yourself

I have asked the Mentors to close this thread.

 

[Jarek 31]

Where I promote my view?
I am just asking if measurement invalidates CPT theorem?
So how do you understand it? What would be your answer?

 

[fresh_42]

Temporarily closed for moderation.

 

[berkeman]

Schwinger doesn't say any of that either.

Since it's clear that:
a. You misunderstand what CPT says, and
b. You are more interested in promoting your own flawed view than in gaining understanding yourself

I have asked the Mentors to close this thread.

After a Mentor discussion, this thread will remain closed.