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Carroll Expansion of General Relativity

by Dennis Hansen, Niels A. Obers, Gerben Oling, Benjamin T. Søgaard

This Submission thread is now published as

Submission summary

Authors (as registered SciPost users): Gerben Oling
Submission information
Preprint Link: https://arxiv.org/abs/2112.12684v4  (pdf)
Date accepted: 2022-07-29
Date submitted: 2022-07-27 04:42
Submitted by: Oling, Gerben
Submitted to: SciPost Physics
Ontological classification
Academic field: Physics
Specialties:
  • Gravitation, Cosmology and Astroparticle Physics
  • High-Energy Physics - Theory
Approach: Theoretical

Abstract

We study the small speed of light expansion of general relativity, utilizing the modern perspective on non-Lorentzian geometry. This is an expansion around the ultra-local Carroll limit, in which light cones close up. To this end, we first rewrite the Einstein-Hilbert action in pre-ultra-local variables, which is closely related to the 3+1 decomposition of general relativity. At leading order in the expansion, these pre-ultra-local variables yield Carroll geometry and the resulting action describes the electric Carroll limit of general relativity. We also obtain the next-to-leading order action in terms of Carroll geometry and next-to-leading order geometric fields. The leading order theory yields constraint and evolution equations, and we can solve the evolution analytically. We furthermore construct a Carroll version of Bowen-York initial data, which has associated conserved boundary linear and angular momentum charges. The notion of mass is not present at leading order and only enters at next-to-leading order. This is illustrated by considering a particular truncation of the next-to-leading order action, corresponding to the magnetic Carroll limit, where we find a solution that describes the Carroll limit of a Schwarzschild black hole. Finally, we comment on how a cosmological constant can be incorporated in our analysis.

Author comments upon resubmission

We thank both referees for their second report. We have clarified the point raised in Report 2 and we have rewritten the relevant paragraph.

List of changes

The paragraph directly below Equation (2.30) has been rewritten.

Published as SciPost Phys. 13, 055 (2022)

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