Lorentz violation in the linearized gravity

TL;DR

This paper explores the effects of Lorentz violation in linearized gravity, analyzing how such modifications alter gravitational wave dispersion and proposing mechanisms for their theoretical origin.

Contribution

It introduces a Lorentz-violating term in linearized gravity and discusses two mechanisms for its generation, expanding understanding of potential Lorentz symmetry breaking in gravity.

Findings

Modified dispersion relations for gravitational waves

Lorentz violation can be induced by quantum coupling to spinor fields

Alternative origin via noncommutative field modifications

Abstract

We study some physical consequences of the introduction of a Lorentz-violating modification term in the linearized gravity, which leads to modified dispersion relations for gravitational waves in the vacuum. We discuss two possible mechanisms for the induction of such a term in the Lagrangian. First, it is generated at the quantum level by a Lorentz-breaking coupling of the gravity field to a spinor field. Second, it appears as consequence of a particular modification of the Poisson algebra of the canonical variables, in the spirit of the so-called ``noncommutative fields approach''.