Graduate Bell's theorem mathematical content

Click For Summary
SUMMARY

This discussion centers on the mathematical foundations of Bell's theorem, particularly the derivation of inequalities related to quantum mechanics (QM) and local hidden-variable theories. Key references include Bell's original 1964 paper, specifically equations (1) and (14), which outline the spinorial representation of rotations and the mathematical structure underlying the theorem. The conversation emphasizes the importance of understanding the theorem's assumptions without philosophical biases, focusing on the algebraic and geometric aspects of the proof, including the role of probability spaces and random variables.

PREREQUISITES
  • Understanding of Bell's theorem and its implications in quantum mechanics.
  • Familiarity with algebraic structures, specifically spinorial representations and group theory.
  • Knowledge of probability theory, particularly the construction of probability spaces.
  • Basic comprehension of quantum mechanics, including the EPR experiment and the Born rule.
NEXT STEPS
  • Study Bell's original 1964 paper to understand the mathematical derivations in detail.
  • Explore the concept of spinorial representations and their applications in quantum mechanics.
  • Research the implications of the Born rule in quantum probability theory.
  • Investigate the relationship between the Bloch sphere and quantum state representations.
USEFUL FOR

Mathematicians, physicists, and students of quantum mechanics seeking a deeper understanding of Bell's theorem and its mathematical underpinnings, as well as those interested in the philosophical implications of quantum theory.

  • #31
RockyMarciano said:
Once again this thread is not about that, it discusses something previous to laying out the abstract probabilistic conditions that a theory fulfilling the EPR experiment must have. What the theorem says is not that all theories satisfying the inequality must be of certain type,

No, that's backwards. It proves that all theories of a certain type satisfy the inequality.

but rather that those that want to replicate all QM predictions (confirmed empirically) must violate them

He proved that all theories of a certain type satisfy a particular inequality. EPR experiments do not satisfy that inequality. Therefore, EPR experiments cannot be explained by a theory of that type.

There is nothing in Bell's argument that relies on any property of quantum mechanics. The fact that EPR violates his inequality is an empirical matter.
 
Physics news on Phys.org
  • #32
zonde said:
Maybe it's trivial, but think it is good idea to put conditions of Bell theorem into mathematical form before doing the same thing with assumptions. So I propose these conditions:
  1. We can produce series of paired events ##A_\alpha## and ##B_\beta## where ##\alpha## and ##\beta## are freely changeable parameters. ##A_\alpha## and ##B_\beta## each can be split into two subevents: ##A_\alpha=\pm 1## and ##B_\beta=\pm 1##.
  2. For every i-th pair of events ##A_{\alpha i}## and ##B_{\beta i}## in series, ##P(A_{\alpha i}=+1, B_{\beta i}=+1)=0## and ##P(A_{\alpha i}=-1, B_{\beta i}=-1)=0## whenever ##\alpha = \beta##.
@RockyMarciano, do these seem fine to you?
Again, the goal of this thread is not directly concerned with the probabilities that lead to the Bell inequalities other than for the fact that all the physical theories with the minimal common mathematical description I'm trying to reach consensus about will certainly satisfy the inequalities when using classicall probabilities on them. The advantage is that by identifying the principal features of this physical theories spaces and mathematical objects in them that directly lead to satisfying the inequality(because that is a feature of EPR math models) it would be so much easier to discard from the beguinning a lot of mathematical models for physics that are not compatible with experiment.
 
  • #33
RockyMarciano said:
Again, the goal of this thread is not directly concerned with the probabilities that lead to the Bell inequalities

Your first post asked what is "the best way to characterize the main assumption from which the probabilities are constructed?"
 
  • #34
Wait, first let's clarify what I mean by EPR experiment and EPR mode, I refer to Einstein's so called "local realist" model, and to the gedanken experiment operational requirements and assumptions not to the actual Aspect type experiments outcomes showing the violations.

stevendaryl said:
No, that's backwards. It proves that all theories of a certain type satisfy the inequality.
And therefore that those that don't satisfy them like the QM predictions or those appparently compatible with nature don't. This is what I'm saying. It is not backwards.

He proved that all theories of a certain type satisfy a particular inequality. EPR experiments do not satisfy that inequality. Therefore, EPR experiments cannot be explained by a theory of that type.
Sure, look tho the possible source of confusion here above.
There is nothing in Bell's argument that relies on any property of quantum mechanics. The fact that EPR violates his inequality is an empirical matter.
Of course. Again there might be some trivial misunderstanding here, see the first commnet of this post.
 
  • #35
RockyMarciano said:
Wait, first let's clarify what I mean by EPR experiment and EPR mode, I refer to Einstein's so called "local realist" model, and to the gedanken experiment operational requirements and assumptions not to the actual Aspect type experiments outcomes showing the violations.
Yes, please clarify these operational requirements of gedanken experiment in mathematical form as it seems you are not satisfied with my attempt in post #29.
 
  • #36
This thread doesn't show much chance of being productive.

In particular, I would like to remind everyone that PhysicsForums is not aimed at the development of physics, but rather at helping understand it.

Thread closed.
 

Similar threads

  • · Replies 28 ·
Replies
28
Views
2K
  • · Replies 333 ·
12
Replies
333
Views
19K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 47 ·
2
Replies
47
Views
5K
Replies
18
Views
2K
  • · Replies 82 ·
3
Replies
82
Views
10K
  • · Replies 58 ·
2
Replies
58
Views
5K
  • · Replies 2 ·
Replies
2
Views
574
  • · Replies 59 ·
2
Replies
59
Views
10K
  • · Replies 197 ·
7
Replies
197
Views
33K