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Main Authors: Chakravarti, Kabir, Reza, Amit, Trombetta, Leonardo G.
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2405.10127
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author Chakravarti, Kabir
Reza, Amit
Trombetta, Leonardo G.
author_facet Chakravarti, Kabir
Reza, Amit
Trombetta, Leonardo G.
contents Hairy black-holes are a unique prediction of certain theories that extend General Relativity (GR) with a scalar field. The presence of scalar hair is reflected non-trivially in the entropy of the black hole along with any topological coupling that may be present in the action. Demanding that a system of two merging black holes obeys the global second law of thermodynamics imposes a bound on this topological coupling coefficient. In this work we study how this bound is pushed from its GR value by the presence of scalar hair by considering estimates of binary black-hole merger parameters through inference studies of both mock and real gravitational-wave (GW) events. Although the scalar charge may produce a statistically significant deviation of the change in entropy over the GR prediction, we find no evidence of this happening in the data from real GW events taken from GWTC-1. We also find the entropy change to be susceptible to biases arising out of GW inferences which ends up being two orders of magnitude larger, therefore overwhelming any change, if at all, induced by the scalar hair.
format Preprint
id arxiv_https___arxiv_org_abs_2405_10127
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Mergers of hairy black holes: Constraining topological couplings from entropy
Chakravarti, Kabir
Reza, Amit
Trombetta, Leonardo G.
General Relativity and Quantum Cosmology
Hairy black-holes are a unique prediction of certain theories that extend General Relativity (GR) with a scalar field. The presence of scalar hair is reflected non-trivially in the entropy of the black hole along with any topological coupling that may be present in the action. Demanding that a system of two merging black holes obeys the global second law of thermodynamics imposes a bound on this topological coupling coefficient. In this work we study how this bound is pushed from its GR value by the presence of scalar hair by considering estimates of binary black-hole merger parameters through inference studies of both mock and real gravitational-wave (GW) events. Although the scalar charge may produce a statistically significant deviation of the change in entropy over the GR prediction, we find no evidence of this happening in the data from real GW events taken from GWTC-1. We also find the entropy change to be susceptible to biases arising out of GW inferences which ends up being two orders of magnitude larger, therefore overwhelming any change, if at all, induced by the scalar hair.
title Mergers of hairy black holes: Constraining topological couplings from entropy
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2405.10127