Gravitons as Goldstone Modes and the Spontaneous Symmetry Breaking of Diffeomorphism Invariance

TL;DR

This paper explores the idea that gravitons can be viewed as Goldstone modes resulting from spontaneous symmetry breaking of diffeomorphism invariance in general relativity, linking classical and quantum perspectives.

Contribution

It introduces a novel interpretation of gravitons as Goldstone excitations and analyzes the role of the metric and spacetime as order parameters in a quantum gravity context.

Findings

Gravitons can be understood as Goldstone modes of broken diffeomorphism symmetry.

The metric and spacetime manifold act as macroscopic order parameters.

Possible phase transitions in the early universe are discussed.

Abstract

We complement investigations of the gauge structure of general relativity with an analysis of the physical consequences of the spontaneous breaking of diffeomorphism invariance which manifests itself in e.g. the socalled Einstein hole problem. We analyze the nature of the gravitons as Goldstone excitations both in the classical and the quantum case. We show that the metrical field and the classical space-time manifold play the role of an order parameter field and order parameter manifold as macroscopic super structures living in an underlying presumed quantum space-time. We furthermore relate our observations to possible phase transitions in some pre big-bang era.