Quasilocal energy in modified gravity

TL;DR

This paper introduces a generalized method for defining quasilocal energy in scalar-tensor gravity, extending previous concepts without relying on symmetries or specific spacetime conditions.

Contribution

It proposes a new approach to quasilocal energy in scalar-tensor gravity by rewriting field equations as effective Einstein equations and applying standard mass definitions.

Findings

Generalization applicable without symmetry assumptions

Provides a straightforward method for scalar-tensor theories

Enhances understanding of energy localization in modified gravity

Abstract

A new generalization of the Hawking-Hayward quasilocal energy to scalar-tensor gravity is proposed without assuming symmetries, asymptotic flatness, or special spacetime metrics. The procedure followed is simple but powerful and consists of writing the scalar-tensor field equations as effective Einstein equations and then applying the standard definition of quasilocal mass.