Graviton Excitations and Lorentz-Violating Gravity with Cosmological Constant

TL;DR

This paper develops a systematic method to analyze the excitation spectrum of gravity models with Lorentz symmetry violation, including Chern-Simons terms, and computes graviton propagators in various scenarios.

Contribution

It introduces a comprehensive set of spin-type operators to account for Lorentz violation in gravity actions and derives graviton propagators considering all orders of the violation parameter.

Findings

Complete set of spin-type operators for Lorentz-violating gravity

Explicit graviton propagators in different Lorentz-violating scenarios

Framework for analyzing Lorentz symmetry breaking in gravitational models

Abstract

Motivated by the interest raised by the problem of Lorenz-symmetry violating gauge theories in connetion with gravity models, this contribution sets out to provide a general method to systematically study the excitation spectrum of gravity actions which include a Lorentz-symmetry breaking Chern-Simons-type action term for the spin connection. A complete set of spin-type operators is found which accounts for the (Lorentz) violation parameter to all orders and graviton propagators are worked out in a number of different situations.