Pith. sign in

REVIEW 22 cited by

The Entropy of Dynamical Black Holes

Not yet reviewed by Pith; the record is open.

This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.

SPECIMEN: schema-true, not a live event

T0 review · schema-true

One-sentence machine reading of the paper's core claim.

pith:XXXXXXXX · record.json · timestamp

arxiv 2402.00818 v2 pith:I6OOY3PS submitted 2024-02-01 hep-th gr-qc

The Entropy of Dynamical Black Holes

classification hep-th gr-qc
keywords entropyblackholeformulageneralorderseconddynamical
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved
0 comments
Share X Bluesky LinkedIn Reddit HN
read the original abstract

We propose a new formula for the entropy of a dynamical black hole$-$valid to leading order for perturbations off of a stationary black hole background$-$in an arbitrary classical diffeomorphism covariant Lagrangian theory of gravity in $n$ dimensions. In stationary eras, this formula agrees with the usual Noether charge formula, but in nonstationary eras, we obtain a nontrivial correction term. In general relativity, our formula for the entropy of a dynamical black hole is $1/4$ of the horizon area plus a term involving the integral of the expansion of the null generators of the horizon, which we show is $1/4$ of the area of the apparent horizon to leading order. Our formula for entropy in a general theory of gravity obeys a "local physical process version" of the first law of black hole thermodynamics. For first order perturbations sourced by external matter that satisfies the null energy condition, our entropy obeys the second law of black hole thermodynamics. For vacuum perturbations, the second law is obeyed at leading order if and only if the "modified canonical energy flux" is positive (as is the case in general relativity but presumably would not hold in general theories). We obtain a general relationship between our formula for the entropy of a dynamical black hole and a formula proposed independently by Dong and by Wall. We then consider the generalized second law in semiclassical gravity for first order perturbations of a stationary black hole. We show that the validity of the quantum null energy condition (QNEC) on a Killing horizon is equivalent to the generalized second law using our notion of black hole entropy but using a modified notion of von Neumann entropy for matter. On the other hand, the generalized second law for the Dong-Wall entropy is equivalent to an integrated version of QNEC, using the unmodified von Neumann entropy for the entropy of matter.

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Forward citations

Cited by 22 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. Trapped Surface as a Cosmic Censor

    gr-qc 2026-06 unverdicted novelty 7.0

    A trapped-surface criterion, derived under null convergence and generic conditions, rules out superextremal Reissner-Nordström, Kerr-Newman, and related final states in overcharging thought experiments without using a...

  2. The BEF Symplectic Form: A Lagrangian Perspective

    hep-th 2026-04 unverdicted novelty 7.0

    The BEF symplectic form is derived from L∞-Lagrangians via covariant phase space methods and coincides with the Barnich-Brandt form for second-order equations of motion.

  3. Thermodynamics of dynamical black holes beyond perturbation theory

    gr-qc 2026-03 accept novelty 7.0

    The authors derive non-perturbative first and second laws for dynamical black holes, identifying entropy with the area of local marginally trapped surfaces rather than the global event horizon.

  4. Holography in the linearized quantum gravity regime and modular crossed product

    hep-th 2026-07 conditional novelty 6.0

    At linearized order, the vacuum-subtracted HRT entropy of a boundary region is the entropy of a coherent graviton state in the modular crossed-product algebra of the dual CFT, assuming a wedge-reconstructing holographic map.

  5. Gravitational Memory Beyond Null Infinity through Finite-Distance Carrollian Screens

    hep-th 2026-07 conditional novelty 6.0

    Finite-distance null screens carry a Carrollian memory whose leading tracefree large-radius part reproduces the standard Bondi displacement memory in Robinson–Trautman spacetimes.

  6. Covariant phase space approach to noncommutativity in tensile and tensionless open strings

    hep-th 2026-04 unverdicted novelty 6.0

    Covariant phase space analysis shows tensionless open strings in constant Kalb-Ramond background have purely boundary-supported phase space with noncommutative endpoint coordinates, recovering Seiberg-Witten noncommut...

  7. The BEF Symplectic Form: A Lagrangian Perspective

    hep-th 2026-04 conditional novelty 6.0

    The BEF symplectic form for L∞ field theories is derived from a Lagrangian and shown to equal the Barnich–Brandt form for second-order equations of motion.

  8. Thermodynamics of dynamical black holes beyond perturbation theory

    gr-qc 2026-03 unverdicted novelty 6.0

    Quasi-local dynamical horizons admit a first law for finite, far-from-equilibrium processes and a quantitative second law tying area growth to energy fluxes, so black-hole entropy is the area of marginally trapped surfaces.

  9. Black hole thermodynamics at null infinity. Part 2: Open systems, Markovian dynamics and work extraction from non-rotating black holes

    hep-th 2026-01 conditional novelty 6.0

    Null-infinity black hole thermodynamics is recast as Markovian open-system thermodynamics, with chemical-potential terms identified as extractable work and used to formulate generalized grand-potential laws for Schwar...

  10. Thermodynamics of Black Holes, far from Equilibrium

    gr-qc 2025-12 conditional novelty 6.0

    The paper derives finite, physical-process versions of the first and second laws of black hole thermodynamics for dynamical horizon segments, extending the first law to black holes arbitrarily far from equilibrium.

  11. Covariant phase space and the semi-classical Einstein equation

    hep-th 2025-10 unverdicted novelty 6.0

    A semi-classical symplectic two-form is defined as the sum of the gravitational symplectic form and the Berry curvature of the quantum matter state; it is shown to be independent of the Cauchy slice and to satisfy a q...

  12. Zeroth law of black hole thermodynamics for higher derivative Proca theories

    hep-th 2025-09 conditional novelty 6.0

    The zeroth law of black hole thermodynamics holds to all perturbative orders for higher curvature Einstein-Proca effective field theories.

  13. A comparison of two constructions for dynamical corrections to Wald entropy

    hep-th 2026-07 conditional novelty 5.0

    For small perturbations, the dynamical entropy S_dyn and Wall's entropy S_Wall satisfy S_dyn = (1-v∂_v)S_Wall, and this paper gives a local algorithm that reconstructs S_Wall from S_dyn once a bifurcation-surface cond...

  14. Dynamical Entropy Is a Noether Charge

    hep-th 2026-07 reject novelty 5.0

    A Noether-charge derivation of the known HWZ dynamical entropy for generic null surfaces, whose local second-law proof is invalid as printed because Eq. (19) has the wrong sign in K.

  15. The entropy of black hole under second-order deviation from equilibrium

    gr-qc 2026-06 unverdicted novelty 5.0

    At second order in perturbations of a stationary black hole with bifurcate Killing horizon, entropy equals apparent horizon area under the null energy condition and obeys the second law via a new balance law in covari...

  16. Holographic pressure and volume for black holes

    hep-th 2026-02 unverdicted novelty 5.0

    Introduces a holographic pressure and volume for static spherically symmetric black holes via quasi-local thermodynamics, showing large black holes become extensive in the large-system limit while small ones do not.

  17. Black hole thermodynamics at null infinity. Part 1: Dual Generalized Second Law

    hep-th 2026-01 conditional novelty 5.0

    At future null infinity, the generalized second law for a Schwarzschild black hole becomes the monotonic decrease of a free energy, or grand potential, constructed from the Bondi mass and angular-mode chemical potentials.

  18. Gravitational Entropy

    hep-th 2025-09 conditional novelty 5.0

    Gravitational entropy of horizons is reformulated as a Noether charge from a specially normalized null generator, reproducing the area law for black hole and cosmological horizons without invoking temperature.

  19. Entanglement Entropy and Thermodynamics of Dynamical Black Holes

    hep-th 2025-09 unverdicted novelty 5.0

    In f(R) theories, the replica-method gravitational entropy computed on the apparent horizon matches the Hollands-Wald-Zhang dynamical black hole entropy and satisfies the first law, while the event horizon does not; t...

  20. Semi-classical spacetime thermodynamics

    hep-th 2025-09 unverdicted novelty 5.0

    Derives semi-classical gravity from thermodynamics of stretched light cones in 2D dilaton gravity with explicit conformal anomaly backreaction and shows equations of motion follow from dynamical Wald entropy in Brans-...

  21. The entropy of black hole under second-order deviation from equilibrium

    gr-qc 2026-06 unverdicted novelty 4.0

    The entropy of a dynamical black hole equals the area of its apparent horizon at second order in perturbations when the null energy condition holds.

  22. GGI lectures on boundary and asymptotic symmetries

    hep-th 2025-12 conditional novelty 4.0

    A lecture-note review of boundary and asymptotic symmetries that re-derives the BMS group as the asymptotic symmetry group of Minkowski spacetime alone and constructs an integral Hamiltonian generator for scalar-field...