Key problems in classical and quantum measurement

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Discussion Overview

This discussion revolves around the complexities and foundational issues related to measurement in classical and quantum mechanics. Participants explore the implications of measurement on theoretical frameworks, the nature of observables, and the philosophical underpinnings of measurement processes in both domains.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants argue that the foundations of quantum mechanics are problematic because they heavily rely on the concept of measurement, which is seen as vague and complex.
  • Others suggest that classical mechanics does not reference measurement in its foundations, raising questions about why quantum mechanics should do so.
  • There is a contention regarding the nature of observables in quantum mechanics, with some asserting that they cannot be in superposition while others challenge this view.
  • Participants discuss the practical aspects of measurement, noting that unmeasured particles can still be assumed to have well-defined properties, which contrasts with some theoretical interpretations.
  • Some contributions highlight that the measurement problem exists in both classical and quantum contexts, emphasizing the need for a deeper understanding of how measurements relate to physical facts.
  • There is a critique of traditional foundational discussions for being superficial and not adequately addressing the complexities involved in measurement processes.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the role of measurement in classical and quantum mechanics. The discussion remains unresolved, with differing opinions on the implications of measurement and the nature of observables.

Contextual Notes

Some participants note that the traditional foundations of quantum mechanics may oversimplify the measurement process, while others argue that classical mechanics' predictions can still be compared to measurements. The discussion highlights the unresolved nature of the measurement problem in both fields.

  • #31
Prathyush said:
The well known problem of classical stability of the atom would apply.
Only if you model atoms as composite. But one can model atoms as point particles with effective interactions.

Prathyush said:
Its probably much easier to do if you work with hard potentials
Yes, but then it is not microscopic. The challenge in solving the quantum mechanical measurement problem also goes away if you don't model the detectors as multiparticle systems. Nothing worth doing remains once you take an apparatus as a black box with simplified laws - whether exact reflection classically or some form of collapse quantum mechanically. The foundational challenge is to show how these assumptions are compatible with an underlying microscopic dynamical law. The work by Allahverdyan, Balian and Nieuwenhuizen is relevant only if one is interested in taking up this challenge.

Prathyush said:
You can always construct a domino like effect, with a ball on top of a potential rolling down knocking out other which are heavier etc.
There are indeed papers that address this quantum mechanically, using multiparticle models. Doing the same with classical multiparticle models is an interesting challenge.
 

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