Spacetime Symmetry Breaking and Einstein-Maxwell Theory

TL;DR

This paper presents a vector field model that combines explicit diffeomorphism breaking with spontaneous Lorentz violation, leading to Einstein-Maxwell equations and photons as Nambu-Goldstone modes in a preferred frame.

Contribution

It introduces a novel model with hybrid spacetime symmetry breaking, unifying explicit and spontaneous violations to derive photon behavior within Einstein-Maxwell theory.

Findings

Photons emerge as massless Nambu-Goldstone modes.

The model obeys Einstein-Maxwell equations in a preferred frame.

Comparisons to previous models highlight unique features.

Abstract

A vector model with a hybrid form of spacetime symmetry breaking consisting of explicit diffeomorphism breaking but spontaneous local Lorentz violation is presented. The combined effects of these symmetry breakings give rise to a theory obeying the Einstein-Maxwell equations in a preferred spatially homogeneous and isotropic frame, with photons emerging as massless Nambu-Goldstone modes. Interpretations and possible generalizations of this model are discussed, and comparisons are made to previous models describing photons as Nambu-Goldstone modes.