Apparent Horizons Associated with Dynamical Black Hole Entropy

2025/07/18 by Hideo Furugori, Kanji Nishii, Furugori, Hideo +5 · 2 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Black Holes and Theoretical Physics #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Theory (hep-th) #Noncommutative and Quantum Gravity Theories

paper · doi:10.48550/arxiv.2507.14105

openalex publication_date 2025/07/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We define entropic marginally outer trapped surfaces (E-MOTSs) as a generalization of apparent horizons. We then show that, under first-order perturbations around a stationary black hole, the dynamical black hole entropy proposed by Hollands, Wald, and Zhang, defined on a background Killing horizon, can be expressed as the Wall entropy evaluated on an E-MOTS associated with it. Our result ensures that the Hollands-Wald-Zhang entropy reduces to the standard Wald entropy in each stationary regime of a dynamical black hole, thereby reinforcing the robustness of the dynamical entropy formulation.

Citations

• Test fields and naked singularities: is the second law the cosmic censor?
• Gravitational focusing and horizon entropy for higher-spin fields
• The First Law and Weak Cosmic Censorship for de Sitter Black Holes
• Weak Cosmic Censorship Conjecture Cannot be Violated in Gedanken Experiments
• Marginally outer trapped tubes in de Sitter spacetime
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• Entropy of dynamical black holes
• Weak Cosmic Censorship and Second Law of Black Hole Thermodynamics in Higher Derivative Gravity
• The Quantum Focusing Conjecture Has Not Been Violated
• A Second Law for higher curvature gravity
• General definition of “conserved quantities” in general relativity and other theories of gravity
• The four laws of black hole mechanics
• Black Holes and Entropy
• Particle creation by black holes

Cited by

• A comparison of two constructions for dynamical corrections to Wald entropy
• Entanglement Entropy and Thermodynamics of Dynamical Black Holes

Related

• Entanglement Entropy and Thermodynamics of Dynamical Black Holes
• The entropy of dynamical de Sitter horizons
• Properties of Dynamical Black Hole Entropy
• Black hole entropy from non-Dirichlet sectors, and bounce solution
• Entropy of dynamical black holes