BMS algebra from residual gauge invariance in light-cone gravity

TL;DR

This paper demonstrates that the BMS algebra naturally emerges from residual gauge invariance in four-dimensional light-cone gravity, linking bulk gauge symmetries to asymptotic symmetries.

Contribution

It shows that the BMS algebra arises from residual gauge transformations in light-cone gravity, not just at the boundary, revealing a deeper bulk symmetry structure.

Findings

BMS algebra is realized on physical fields in light-cone gravity.

Residual gauge transformations satisfy the BMS algebra.

Connection between BMS algebra and Hamiltonian quadratic form.

Abstract

We analyze the residual gauge freedom in gravity, in four dimensions, in the light-cone gauge, in a formulation where unphysical fields are integrated out. By checking the invariance of the light-cone Hamiltonian, we obtain a set of residual gauge transformations, which satisfy the BMS algebra realized on the two physical fields in the theory. Hence, the BMS algebra appears as a consequence of residual gauge invariance in the bulk and not just at the asymptotic boundary. We highlight the key features of the light-cone BMS algebra and discuss its connection with the quadratic form structure of the Hamiltonian.