How does the thermal interpretation explain Stern-Gerlach?

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Discussion Overview

The discussion centers on the application of the thermal interpretation of quantum mechanics to the Stern-Gerlach experiment, specifically examining how this interpretation accounts for the observed splitting of a beam of electrons with spin-z up when subjected to a magnetic field oriented in the x direction. Participants explore the implications of the thermal interpretation regarding measurement and the nature of the quantum state of the beam.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions how the thermal interpretation can explain the Stern-Gerlach experiment, noting that the expected q-expectation value for spin-x is zero, which seems inconsistent with the observed splitting of the beam into two distinct paths.
  • Another participant references earlier posts to clarify that in the thermal interpretation, the measurement device is treated classically, raising concerns about the boundary between classical and quantum treatments.
  • Some participants argue that the measurement device in the thermal interpretation is always a quantum device, suggesting that the beam should be interpreted as a quantum field rather than classically.
  • There is a discussion about the implications of measuring a single atom in the beam and how this relates to the observed splitting, with some suggesting that the quantum field's nature allows for a density distribution that leads to the observed results.
  • One participant introduces the concept of "quantum bucket intuition," suggesting that the uncertainty in measurements leads to approximate results that converge to the true value with larger sample sizes.
  • Another participant emphasizes that conservation of mass and the instability of macroscopic superpositions contribute to the observed behavior in the Stern-Gerlach experiment.

Areas of Agreement / Disagreement

Participants express differing views on how the thermal interpretation applies to the Stern-Gerlach experiment, with no consensus reached on the explanation of the observed results. Some participants agree on the need for a quantum field interpretation, while others question the clarity of the boundary between classical and quantum treatments.

Contextual Notes

Participants highlight the limitations in understanding the measurement process and the definitions of classical versus quantum states, particularly in the context of single-particle measurements versus beams of particles.

  • #91
A. Neumaier said:
##H## is a sum of integrals over multilocal operators
Can you better explain what do you mean by that? (Pinpoiting to the right part of your paper would be OK.)
 
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  • #92
Demystifier said:
Can you better explain what do you mean by that? (Pinpointing to the right part of your paper would be OK.)
In my paper I didn't discuss the detailed form of the Hamiltonian of the universe. It depends on stuff yet to be discovered about how to represent quantum gravity. But the general form of the Hamiltonian is already visible from simpler quantum field theories such as QED, where it is derived as usual from the action, and later modified through renormalization.

Already a free Hamiltonian contains a term with a spatial integral over quadratic expressions, and interactions plus renormalization at all orders add terms of all higher degrees, which become multilocal when inserted into the Ehrenfest dynamics. (Search for Hamiltonian in this Wikipedia article to find the explicit unrenormalized expression for scalar field theory; the integration variable runs over points distinct from the ##x## in the Ehrenfest equation.)
 
  • #93
Hi all,

sorry if I post in a relatively old thread.

charters said:
Ok this I can agree is a workable and well understood solution to Bell's theorem. Basically, instead of saying a "pilot wave" is steering the deterministic time evolution of the local pointer variables, the TI says it is "multilocal variables" doing so.

Personally, I do not understand how can one avoid a 'non-locality' of the kind of the pilot-wave theory if multi-local properties dependent on more than one space-like separated space-time regions are accepted. Are there any references on this?
Also, is the thermal interpretation the only one that uses this possible solution to Bell's theorem?
 
  • #94
indefinite_123 said:
I do not understand how can one avoid a 'non-locality' of the kind of the pilot-wave theory if multi-local properties dependent on more than one space-like separated space-time regions are accepted. Are there any references on this?
I discuss nonlocality in Part II of my preprints, Section 4.5, mentioned in post #1 of the main thread on the TI (linked to in post #2 of the present thread) .

For a more polished account of bilocal quantities and nonlocality see my recent book also mentioned there.
 
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  • #95
A. Neumaier said:
I discuss nonlocality in Part II of my preprints, Section 4.5, mentioned in post #1 of the main thread on the TI (linked to in post #2 of the present thread) .

For a more polished account of bilocal quantities and nonlocality see my recent book also mentioned there.
Thank you very much!
 

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