Null Infinity as a Weakly Isolated Horizon

Fuente: arXiv
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Main Authors: Ashtekar, Abhay, Speziale, Simone
Format: Preprint
Published: 2024
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author Ashtekar, Abhay
Speziale, Simone
author_facet Ashtekar, Abhay
Speziale, Simone
contents Null infinity arises as a boundary of the Penrose conformal completion of an asymptotically flat physical space-time. We first note that null infinity is a weakly isolated horizon (WIH), and then show that its familiar properties can be derived from the general WIH framework. This seems quite surprising because physics associated with black hole (and cosmological) WIHs is very different from that extracted at null infinity. We show that these differences can be directly traced back to the fact that null infinity is a WIH in the conformal completion rather than the physical space-time. In particular, the BMS group at null infinity stems from the symmetry group of WIHs. In a companion paper, we obtain fluxes and charges associated with symmetries associated with both null infinity and black hole (and cosmological) horizons using a new Hamiltonian framework. The fact that is there is a single mathematical framework underlying these different situations paves the way to explore the relation between horizon dynamics in the strong field region and waveforms at infinity. It should also be useful in the analysis of black hole evaporation in quantum gravity.
format Preprint
id arxiv_https___arxiv_org_abs_2402_17977
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Null Infinity as a Weakly Isolated Horizon
Ashtekar, Abhay
Speziale, Simone
High Energy Physics - Theory
General Relativity and Quantum Cosmology
Mathematical Physics
Null infinity arises as a boundary of the Penrose conformal completion of an asymptotically flat physical space-time. We first note that null infinity is a weakly isolated horizon (WIH), and then show that its familiar properties can be derived from the general WIH framework. This seems quite surprising because physics associated with black hole (and cosmological) WIHs is very different from that extracted at null infinity. We show that these differences can be directly traced back to the fact that null infinity is a WIH in the conformal completion rather than the physical space-time. In particular, the BMS group at null infinity stems from the symmetry group of WIHs. In a companion paper, we obtain fluxes and charges associated with symmetries associated with both null infinity and black hole (and cosmological) horizons using a new Hamiltonian framework. The fact that is there is a single mathematical framework underlying these different situations paves the way to explore the relation between horizon dynamics in the strong field region and waveforms at infinity. It should also be useful in the analysis of black hole evaporation in quantum gravity.
title Null Infinity as a Weakly Isolated Horizon
topic High Energy Physics - Theory
General Relativity and Quantum Cosmology
Mathematical Physics
url https://arxiv.org/abs/2402.17977