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

[Loren Booda]

In a universe of particles and measurers, does quantum mechanics guarantee the linearity between all possible interactions?

 

[dextercioby]

No.The gravitational interaction is a perfect example of nonlinear interaction...


Daniel.

 

[Loren Booda]

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?

 

[dextercioby]

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.

 

[Loren Booda]

One can construct a nonlinear theory from a linear one, but not vice versa?

 

[dextercioby]

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.