Violation of the equivalence principle in curvature based extended gravity at finite temperature

TL;DR

This paper explores how the Equivalence Principle can be violated at finite temperature within curvature-based extended gravity theories, using quantum field theory and generalized Einstein equations, with specific models analyzed.

Contribution

It demonstrates the derivation of Equivalence Principle violation from quantum field theory at finite temperature and applies this to various extended gravity models.

Findings

Equivalence Principle violation can be derived from quantum field theory at non-zero temperature.

Generalized Einstein equations with temperature-dependent energy-momentum tensor can recover this violation.

Quantitative analysis of violation in Brans-Dicke, Standard Model Extension, and Conformal Gravity models.

Abstract

We review the possible violation of the Equivalence Principle at finite temperature T in the framework of curvature based Extended Theories of Gravity. Specifically, we first show how it is possible to derive Equivalence Principle violation from Quantum Field Theory at non-vanishing T. Subsequently, we exhibit how this result can be precisely recovered by following an alternative path that envisages the employment of generalized Einstein equations with a temperature-dependent energy-momentum tensor. Finally, we adopt the latter formalism in the context of some Extended Gravity models to quantify the amount of Equivalence Principle violation. Specifically, Brans-Dicke Theory, Standard Model Extension and Conformal Gravity are considered in details.