The Operational Meaning of Total Energy of Isolated Systems in General Relativity

TL;DR

This paper explores thought experiments to measure different notions of total energy in isolated systems within general relativity, highlighting potential applications in quantum gravity.

Contribution

It introduces a protocol for measuring Bondi-Sachs energy and discusses its relevance to non-perturbative loop quantum gravity.

Findings

Proposes thought experiments for energy measurement in GR

Identifies the Bondi-Sachs energy as a promising operator in quantum gravity

Suggests broader applications of the energy expression

Abstract

We present thought experiments to measure the Arnowitt-Deser-Misner and Bondi-Sachs energy of isolated systems in general relativity. The expression of the Bondi-Sachs energy used in the protocol is likely to have other applications. In particular, it is well-suited to to be promoted to an operator in non-perturbative loop quantum gravity.