Gravitational Coleman-Weinberg Mechanism

TL;DR

This paper explores how scale symmetry breaking via quantum loop corrections can generate scalar masses in gravitational theories without explicit energy scales, extending the Coleman-Weinberg mechanism to gravity.

Contribution

It introduces the gravitational Coleman-Weinberg mechanism, analyzing scalar mass generation and symmetry breaking in a scale-invariant gravitational framework.

Findings

Derived gravitational Coleman-Weinberg potentials

Identified parameter space for symmetry breaking

Calculated scalar masses in the gravitational context

Abstract

The Coleman-Weinberg mechanism provides a procedure by which a scalar field, which initially has no mass parameters, acquires a mass due to the anomalous nature of scale symmetry. Loop corrections trigger a spontaneous symmetry breaking and the appearance of a non-trivial vacuum. We first review the basic example of the ColemanWeinberg mechanism, scalar Quantum Electrodynamics, in a perturbative regime where the scalar particle becomes massive through photon loops. We then present the main results of this article, what we name the gravitational Coleman-Weinberg mechanism: we analyse the same effect in a gravitational theory without explicit energy scales at tree-level. Finally, we also study the mechanism for two scalar fields in the mentioned gravitational theory. We will derive the gravitational Coleman-Weinberg potentials, analyse the parameter space where we have a symmetry breaking, and obtain the value of the corresponding scalar masses.