Institut de Recherche sur les Lois Fondamentales de l'Univers

Lorentz non-invariance in quantum field theory is reconsidered as well as its interplay with gravity,  diffeomorphism invariance
and changing reference frames. We clarify these issues, and argue that Lorentz violation is always an environmental effect.
We provide a holographic view of the breaking, and its connection to Horava-Lifshitz type of gravitational theories.
We also argue that dissipation is always a signal of Lorentz violation. We provide calculations of dissipation at strong coupling.