So simple yet so problematic

[Athe]

If we consider a system (say an electron) with respect his own reference frame, we find that it is placed in an exact position (let's say the origin) and it has an exact momentum (it is at rest with respect to his own reference frame); due the very definition of such reference frame.

HEISENBERG O_O

Quantum mechanics excludes the existence of proper reference frames?. If so, what happens with proper time?. Can we talk about simultaneity when dealing with quantum mechanics? Do 'simultaneous measurements' (of non-cunmuting observables or whatever) have sense?

 

[ZapperZ]

If we consider a system (say an electron) with respect his own reference frame, we find that it is placed in an exact position (let's say the origin) and it has an exact momentum (it is at rest with respect to his own reference frame); due the very definition of such reference frame.

HEISENBERG O_O

Quantum mechanics excludes the existence of proper reference frames?. If so, what happens with proper time?. Can we talk about simultaneity when dealing with quantum mechanics? Do 'simultaneous measurements' (of non-cunmuting observables or whatever) have sense?

The problem here is that you made an explicit assumption that is your starting point which is not substantiated by evidence. You have made an explicit assumption that an "electron" is a point object like a tennis ball that can be defined clearly as to where it is in such a way that you can transform to its reference frame. How are you sure this is valid when there's plenty of indication that a "smearing" of position simultaneously can also be interpreted for the electron? Look at H2 bonding or even atomic orbitals for examples.

When you start off with the wrong premise, then any kinds of nonsensical conclusion can be possible. We don't have such luxury in physics. The parameters and scenario that we can use must be based on some ground of something realistic. Unrealistic assumption will result in unrealistic results.

Zz.

 

[Athe]

The problem here is that you made an explicit assumption that is your starting point which is not substantiated by evidence. You have made an explicit assumption that an "electron" is a point object like a tennis ball that can be defined clearly as to where it is in such a way that you can transform to its reference frame. How are you sure this is valid when there's plenty of indication that a "smearing" of position simultaneously can also be interpreted for the electron? Look at H2 bonding or even atomic orbitals for examples.
QUOTE]


I don't want to complain, I just want answers. I want to study a quantum system of two particles in a minkowskian space-time, and I have just realized I have no clue of how to draw their universe lines. I want to perform a simultaneous measurement in each of them, first simultaneous with respect the laboratory frame and then with respect an inertial frame moving with velocity v respect to the former.'Classically', the particles are at rest respect to the lab frame, separated by a space-like interval. But with Heisenberg operating...
How do quantum mechanics define the proper reference frame of a system?