Lorentz-violating massive gauge and gravitational fields

TL;DR

This paper explores Lorentz-violating massive gravity models, identifying a stable theory with unique properties like only two propagating degrees of freedom and long-range instantaneous interactions, with implications for causality and phenomenology.

Contribution

It presents a stable Lorentz-violating massive gravity model with unusual properties, expanding understanding of possible consistent theories.

Findings

Identified a stable Lorentz-violating massive gravity model

Discovered models with long-range instantaneous interactions

Analyzed causality and phenomenological implications of these models

Abstract

We study nonlinear dynamics in models of Lorentz-violating massive gravity. The Boulware-Deser instability restricts severely the class of acceptable theories. We identify a model that is stable. It exhibits the following bizarre but interesting property: there are only two massive propagating degrees of freedom in the spectrum, and yet long-range instantaneous interactions are present in the theory. We discuss this property on a simpler example of a photon with a Lorentz-violating mass term where the issues of (a)causality are easier to understand. Depending on the values of the mass parameter these models can either be excluded, or become phenomenologically interesting. We discuss a similar example with more degrees of freedom, as well as a model without the long-range instantaneous interactions.