Is the entire system of quantum observers and objects relatively linear?

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Discussion Overview

The discussion revolves around the nature of linearity in quantum mechanics and its interactions with gravitational forces. Participants explore whether quantum mechanics guarantees linearity in all interactions, particularly in the context of gravitational nonlinearity and the implications of measurement on perceived linearity.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants question whether quantum mechanics ensures linearity in all interactions, suggesting that gravitational interactions are inherently nonlinear.
  • Others propose that the coexistence of gravitational and quantum mechanical interactions introduces nonlinearity where linearity is typically expected.
  • One participant raises the idea that the perceived linearity or nonlinearity of a system may depend on the type of measurement performed.
  • There is a discussion about the correspondence principle and its implications for the transformation between macroscopic gravitational situations and microscopic quantum mechanics.
  • Some participants note that while one can derive nonlinear theories from linear ones, the reverse is not necessarily true, particularly in the context of gravity and quantum field theories.
  • Concerns are raised about the validity of linear approximations in the context of weak gravitational fields and the challenges in confirming linearized theories through experiments.

Areas of Agreement / Disagreement

Participants express disagreement regarding the nature of linearity in quantum mechanics and its relationship with gravitational interactions. Multiple competing views are presented, and the discussion remains unresolved.

Contextual Notes

Limitations include the ambiguity in definitions of "linearity," the dependence on specific measurement types, and the unresolved nature of how gravitational interactions integrate with quantum mechanics.

Loren Booda
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In a universe of particles and measurers, does quantum mechanics guarantee the linearity between all possible interactions?
 
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No.The gravitational interaction is a perfect example of nonlinear interaction...


Daniel.
 
Though gravitation exists, must it not co-exist with quantum mechanical interactions, that is, bestow nonlinearity where linearity is usually considered the rule? How does the graviton quantum justify this ambiguity? Does not the correspondence principle infer a gradual transformation between macroscopic gravitational (nonlinear) situations and those microscopically quantum mechanical (linear)? Could the perceived (non)linearity of a system depend primarily on the type of measurement performed upon it?
 
What exactly do you mean by "linearity"...?For example,QCD and EW are both nonlinear field theories...I have no idea what you meant by "correspondence principle infer a gradual transformation between macroscopic gravitational (nonlinear) situations and those microscopically quantum mechanical (linear)"...

As for the last question,i frankly doubt there would be any connection in the sense you described,more viceversa:linearity is confirmed or infirmed by measurements...

Daniel.
 
One can construct a nonlinear theory from a linear one, but not vice versa?
 
Both ways;of course,it's easier to linearize,but,for gravity for example,it's just an approximation valid for weak fields (waves included)...As for QCD or EW,basically everything is lost...I doubt any experiment would confirmed the linearized theories...

Daniel.
 

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