Heisenberg Soft Hair on Robinson-Trautman Spacetimes

Fuente: arXiv
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Autori principali: Adami, H., Parvizi, A., Sheikh-Jabbari, M. M., Taghiloo, V.
Natura: Preprint
Pubblicazione: 2024
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author Adami, H.
Parvizi, A.
Sheikh-Jabbari, M. M.
Taghiloo, V.
author_facet Adami, H.
Parvizi, A.
Sheikh-Jabbari, M. M.
Taghiloo, V.
contents We study 4 dimensional $(4d$) gravitational waves (GWs) with compact wavefronts, generalizing Robinson-Trautman (RT) solutions in Einstein gravity with an arbitrary cosmological constant. We construct the most general solution of the GWs in the presence of a causal, timelike, or null boundary when the usual tensor modes are turned off. Our solution space besides the shape and topology of the wavefront which is a generic compact, smooth, and orientable $2d$ surface $Σ$, is specified by a vector over $Σ$ satisfying the conformal Killing equation and two scalars that are arbitrary functions over the causal boundary, the boundary modes (soft hair). We work out the symplectic form over the solution space using covariant phase space formalism and analyze the boundary symmetries and charges. The algebra of surface charges is a Heisenberg algebra. Only the overall size of the compact wavefront and not the details of its shape appears in the boundary symplectic form and is canonical conjugate to the overall mass of the GW. Hence, the information about the shape of the wavefront can't be probed by the boundary observer. We construct a boundary energy-momentum tensor and a boundary current, whose conservation yields the RT equation for both asymptotically AdS and flat spacetimes. The latter provides a hydrodynamic description for our RT solutions.
format Preprint
id arxiv_https___arxiv_org_abs_2402_17658
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Heisenberg Soft Hair on Robinson-Trautman Spacetimes
Adami, H.
Parvizi, A.
Sheikh-Jabbari, M. M.
Taghiloo, V.
High Energy Physics - Theory
General Relativity and Quantum Cosmology
We study 4 dimensional $(4d$) gravitational waves (GWs) with compact wavefronts, generalizing Robinson-Trautman (RT) solutions in Einstein gravity with an arbitrary cosmological constant. We construct the most general solution of the GWs in the presence of a causal, timelike, or null boundary when the usual tensor modes are turned off. Our solution space besides the shape and topology of the wavefront which is a generic compact, smooth, and orientable $2d$ surface $Σ$, is specified by a vector over $Σ$ satisfying the conformal Killing equation and two scalars that are arbitrary functions over the causal boundary, the boundary modes (soft hair). We work out the symplectic form over the solution space using covariant phase space formalism and analyze the boundary symmetries and charges. The algebra of surface charges is a Heisenberg algebra. Only the overall size of the compact wavefront and not the details of its shape appears in the boundary symplectic form and is canonical conjugate to the overall mass of the GW. Hence, the information about the shape of the wavefront can't be probed by the boundary observer. We construct a boundary energy-momentum tensor and a boundary current, whose conservation yields the RT equation for both asymptotically AdS and flat spacetimes. The latter provides a hydrodynamic description for our RT solutions.
title Heisenberg Soft Hair on Robinson-Trautman Spacetimes
topic High Energy Physics - Theory
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2402.17658