Building on QP from 5 reasonable axioms

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    Axioms Building
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Discussion Overview

The discussion revolves around the foundational aspects of quantum physics as articulated in Lucien Hardy's "Quantum Theory From Five Reasonable Axioms." Participants explore the implications of state space connectivity and its mathematical nature, as well as the etiquette and requirements for sharing related papers in the forum.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Meta-discussion

Main Points Raised

  • One participant expresses that Hardy's work has inspired them to write a paper on the deducibility of "connectedness" in state space rather than assuming it.
  • Another participant questions the mathematical nature of the "state space" being considered, prompting further exploration of its properties.
  • Some participants discuss the implications of postulating connectivity in state space, noting that it leads to quantum physics as demonstrated by Hardy.
  • One participant mentions that a disconnected state space could consist of two parallel circles on the Bloch sphere, which raises questions about the existence of a corresponding level-3 state space in R^9.
  • Concerns are raised regarding the publication status of Hardy's paper, with some participants noting it is available on arXiv but may not be peer-reviewed.
  • Suggestions are made for the original poster to consider submitting their paper to specific journals or to publish an insights article on the forum.
  • One participant provides a detailed explanation of generalized probability models, relating it to the foundations of quantum mechanics and the assumptions made in Hardy's work.
  • Another participant expresses interest in the original poster's discoveries and the implications of their findings.

Areas of Agreement / Disagreement

The discussion contains multiple competing views regarding the assumptions about state space connectivity and its implications for quantum physics. Participants have not reached a consensus on the best approach to these foundational questions.

Contextual Notes

Participants note that the discussion of Hardy's paper is acceptable despite its availability only on arXiv, as it has been cited in reputable sources. There are also unresolved questions regarding the nature of state space and its mathematical properties.

  • #31
normvcr said:
Why is the probability of state transitions symmetric? i.e. P( S transitions to T) = P( T transitions to S )
Fra said:
How about the ergodic hypothesis applied to the histories in the state of microstates? ...
This got me to thinking. There is some principal that a system should be able to evolve to maximum entropy. Perhaps, this can form the core of an argument that the transition probabilities are symmetric. This might also not pan out at all ...
 
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  • #32
normvcr said:
This got me to thinking. There is some principal that a system should be able to evolve to maximum entropy. Perhaps, this can form the core of an argument that the transition probabilities are symmetric. This might also not pan out at all ...
[bayes theorem] P(T|S) = P(S|T) * P(T)/P(S)
and
[ergodic hypothesis] P(S) = P(T)
=> P(T|S) = P(S|T)

or were you seeking something more subtle?, this applies only to pure microstates though.

/Fredrik
 
  • #33
Fra said:
[bayes theorem] P(T|S) = P(S|T) * P(T)/P(S)
and
[ergodic hypothesis] P(S) = P(T)
=> P(T|S) = P(S|T)
... this applies only to pure microstates though.
/Fredrik
Clever argument. The fly in the ointment is that since P(T|S)=P(S|T), then we always will have P(T)=P(S), even when not at equilibrium. The analysis needs to take place in a somewhat more complex context: P(T|S) manifests itself when a measurement is done for T, in initial state S, and vice versa for P(S|T).
It is sufficient to work with microstates (pure states). Symmetry for mixed states would then follow from linearity of the transition probabilities.
 
  • #34
normvcr said:
Clever argument. The fly in the ointment is that since P(T|S)=P(S|T), then we always will have P(T)=P(S), even when not at equilibrium.

Yes if we are introducing another state (some macrostate) which "equiliirium" refers to, then one needs to make that explicit in the formulas, ie we are then not just talking about an uncertaint microstate, but also an uncertain macrostate. Its also along these paths, and when associating the macrostate to an observer as an inferential agent in its envirnoment, and ponder about its "expectations on evolution", then you can connect arrow of time to the observer depedent directions
that you start to get into the objections i had before.But i will not ramble too much about that, becauase is am quote sure most arent going to see my point anyway and this is the wrong place to explain my whole idea anyway. But i think there is a lot of interesting stuff in these inferential structures! So good luck with your paper, without know what stance you take!

/Fredrik
 
  • #35
normvcr said:
I will ... see if the journal is interested, and let you guys know how it turns out.
The paper was turned down by the journal, for reasons that I accept -- "this is an interesting mathematics article, but does not contain sufficient philosophical/conceptual insights to be publishable in ...". This is quite reasonable, given the nature of the journal. I raised two such insights in this thread
  1. Symmetry of probability of state transitions.
  2. The physical states (states that exist in reality) are topologically closed.
However, I did not make a point of underlining these, and other issues in the paper, as I am not trained in physics, and feel it would be presumptive of me to espouse physics to physicists. So, I am in something of a quandary ...
 

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