The discussion centers on the implications of introducing a momentum cutoff in the context of Lorentz violation and its effects on the vacuum state. Participants agree that a preferred frame must be established, leading to a modified understanding of the vacuum, which can only be in the ground state within this frame. The introduction of a momentum cutoff without altering other theoretical aspects results in a computational approximation rather than a fully developed theory. Observations from such a setup indicate that applying a boost in the preferred direction would cause the ground state to appear excited in other frames.
PREREQUISITESThe discussion is beneficial for theoretical physicists, quantum field theorists, and researchers exploring the foundations of particle physics and Lorentz symmetry violations.
Correct. But if Lorentz symmetry is no longer the symmetry of the theory, then it is pretty much pointlesss to even ask how the vacuum (or anything else) looks in other Lorentz frames.asimov42 said:By 'empty' I mean that the vacuum can only be in the ground state in the preferred frame, correct?
An ugly but consistent theory that can be compared with experiments.asimov42 said:Thanks @Demystifier. If one were to do the totally naive thing and introduce a momentum cutoff in the preferred frame, without changing other aspects of the theory, what would one expect to observe?
Yes. I would call it a computational approximation rather than a "theory". Like ignoring the curvature of the Earth in a ballistic calculation.asimov42 said:make the ground state in the preferred frame look excited in another
I think it depends on how exactly do you compute the boost, i.e. what do you keep fixed. Have you tried to do the actual calculation? For free fields it should not be difficult.asimov42 said:Certainly - but then there should be an expected (predicted) observation. For example, applying a boost in the 'right' direction should make the ground state in the preferred frame look excited in another, no?