Quantum mechanics and gravity of Greenberger

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Discussion Overview

The discussion revolves around the interpretation of figure 2 from Greenberger's paper on quantum mechanics and gravity, specifically addressing the implications of phase space representations for harmonic oscillators and classical particles. Participants explore the relationships between mass, momentum, and position in phase space, as well as the relevance of the equivalence principle and the Bohr model of an atom.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants question the validity of figure 2, suggesting that it implies a scenario not possible for a harmonic oscillator, where maximal position and momentum are interdependent.
  • Others propose that Greenberger's illustration may refer to a pair of classical particles with different masses, rather than a single oscillator, which could allow for the depicted phase space representation.
  • One participant notes the relationship between momentum and position amplitudes, acknowledging that a larger mass could maintain the same position amplitude while altering momentum.
  • There is uncertainty regarding the interpretation of equations (19) and (20) from the paper, particularly whether they can apply to harmonic oscillators and how they relate to gravitational and nongravitational forces.

Areas of Agreement / Disagreement

Participants express differing views on the implications of figure 2 and the applicability of harmonic oscillator principles, indicating that multiple competing interpretations exist without a clear consensus.

Contextual Notes

Participants highlight limitations in their understanding of specific equations and the assumptions underlying the relationships between mass, momentum, and position in phase space.

exponent137
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I read paper https://arxiv.org/ftp/arxiv/papers/1011/1011.3719.pdf .
I do not understand figure 2. Such double phase space (x-p) can be also for a harmonic oscillator. But, at a harmonic oscillator we cannot have two ellipses (or a circle and an ellipse) which touch on some points, but have the same center.

Maybe Greenberger thought something more general than Harmonic oscillator?
 
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exponent137 said:
Maybe Greenberger thought something more general than Harmonic oscillator?

I think in Fig. 2 he's assuming something more specific, and different--a pair of classical particles, one with ##K## times the mass of the other. He's just using this as an illustration, so I don't think he intends it to be fully general.
 
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If we look at the equation for a harmonic oscillator, it forms an ellipse in phase space of x and momentum. If we change maximal momentum, maximal x is changed, thus it is not possible an example where maximal x stays the same, but momentum is enlarged. Thus example in figure 2 is not possible. But I think that he ignored this aspect and he concentrates only on the equivalence principle.

He wrote also about Bohr model of an atom, but this one does not form ellipse in phase space of x and momentum. It is valid: ##v^2\propto 1/r##.
 
exponent137 said:
If we look at the equation for a harmonic oscillator, it forms an ellipse in phase space of x and momentum. If we change maximal momentum, maximal x is changed, thus it is not possible an example where maximal x stays the same, but momentum is enlarged.

Did you read my post #2? The circle and the ellipse are not describing two different proposed states for the same particle (or oscillator). They are describing two different particles (or oscillators), one with ##K## times the mass of the other.

exponent137 said:
Thus example in figure 2 is not possible.

It is if you understand what it means. See above.
 
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Yes, I overlooked this relation: ##p_0=mx_0\omega##.
It is valid ##p_0=mx_0\omega## as a relation between amplitudes of momentum and locations.
Thus, new ellipse has the same ##x_0## amplitude when only mass is enlarged.
Thanks for help, although not for a direct answer, because you do not know what I think wrongly. :smile:
 
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1) I am still not sure if I understand eqs. (19) and (20). I think that the right sides of eqs. (20) means that in correspondence limit, (##\rightarrow c_l##), we have only one ##c_l##, thus only one frequency?
https://arxiv.org/ftp/arxiv/papers/1011/1011.3719.pdf

2) That means, we can respect a harmonic oscillator and thus (19) and (20) can also be for a harmonic oscillator?

3) He mentioned gravitational and nongravitational forces. Does Harmonic oscillator can be described for both types of forces, in this paper?
 
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