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Entropy and Temperature of Black 3-Branes

High Energy Physics - Theory · Submitted 25 Feb 1996 · 21 references

Pith's verdict: The scaling match between the black 3-brane horizon area and a 3+1 dimensional blackbody on the D3-brane is real and parameter-free; the coefficient mismatch is acknowledged up front, so the paper's actual claim is narrower than its reputation.

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arXiv IDhep-th/9602135 (version 3)
Pith IDO7XEIZYQ, Pith's permanent record of this paper and its review
CitationA.W. Peet (Princeton University), I.R. Klebanov, S.S. Gubser. "Entropy and Temperature of Black 3-Branes." arXiv:hep-th/9602135 (1996). https://pith.science/paper/O7XEIZYQ
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The paper

The paper claims

Black 3-brane entropy follows a hot open-string gas

The reading

The paper asks whether the horizon entropy of a black 3-brane in type IIB supergravity can be reproduced by counting microstates of the D3-brane that carries the same charge. For a slight departure from extremality, the supergravity entropy scales as $(/delta M/M_0)^{3/4}$, exactly the scaling of a $3+1$ dimensional gas of massless bosons and fermions, which is blackbody radiation. Counting the open-string modes on $n_w$ coincident D3-branes gives an entropy with the same power law and a normalization that matches the horizon-area result if the gas has six effective massless modes per brane rather than the eight expected from the worldvolume gauge theory. The paper also constructs a boosted 3-brane carrying longitudinal momentum and shows that its extremal horizon area still vanishes, consistent with the non-extensive BPS entropy on the D-brane side. If the identification is right, the horizon area is counting the states of a hot gas on the brane, and the Hawking temperature is the temperature of that gas.

What carries the argument

Two calculations carry the argument. On the gravity side, the horizon area of the type IIB 3-brane solution is expressed through the ADM mass and the deviation $/delta M/M_0$, giving $S_{/rm BH}/propto n_w^{5/4}L^3(/delta M/M_0)^{3/4}$. On the brane side, the grand-canonical partition function of a $3+1$ dimensional gas of $N$ massless bosons and fermions on a torus of side $L$ is $Z=/prod_{/vec n/in/mathbb{Z}^3}/left[(1+q^{|/vec n|})/(1-q^{|/vec n|})/right]^N$ with $q=e^{-2/pi/LT}$; it yields $E=/pi^2NL^3T^4/16$ and $S=/pi^2NL^3T^3/12$, so eliminating $T$ gives $S/propto N^{1/4}L^{3/4}E^{3/4}$. The boost of the 3-brane solution supplies the momentum-carrying case and lets the paper compare the extremal horizon area with the BPS entropy.

Extended reading notes

Core claim

The central claim is that a slightly non-extremal black 3-brane has a Bekenstein-Hawking entropy $S_{/rm BH}=2^{5/4}3^{-3/4}/pi^{7/8}n_w^{5/4}/kappa^{-3/4}L^3(/delta M/M_0)^{3/4}$ (Eq. 31) whose energy dependence matches the entropy $S=(2/3)N^{1/4}/sqrt{/pi}/,n_wL^{3/4}E^{3/4}$ (Eq. 24) of a $3+1$ dimensional gas of $N$ massless bosons and fermions on the D3-brane. With the expected $N=8$ the two entropies differ by the factor $(4/3)^{1/4}$; with $N=6$ they agree exactly. The paper calls the $N=8$ mismatch a mysterious numerical factor and does not derive the reduction to six, offering instead an unpublished suggestion about altered gaugino boundary conditions. It also shows that an extremal 3-brane carrying finite longitudinal momentum still has vanishing horizon area, matching the non-extensive BPS entropy of the momentum-carrying D3-brane.

Load-bearing premise

The argument rests on treating the non-BPS excitations of the D3-brane as a free $3+1$ dimensional gas of massless open-string modes and on reducing the expected eight massless modes to six so that the normalizations match, a reduction the paper itself leaves to an unpublished suggestion rather than deriving.

Editorial extensions

If this is right

  • If the matching is not accidental, the Bekenstein-Hawking entropy of a near-extremal D3-brane is the entropy of a $3+1$ dimensional blackbody gas of open strings, with the horizon area counting that gas's microstates.
  • The Hawking temperature is independent of the string coupling and equals the blackbody temperature when the effective mode count is $N=6$; for the expected $N=8$ it differs by the factor $(4/3)^{1/4}$.
  • For $n_w$ coincident D3-branes the gas has $n_w^2$ species, matching the enhanced symmetry of coincident branes.
  • An extremal 3-brane carrying finite longitudinal momentum still has zero horizon area, so unlike the black string, momentum does not stabilize a horizon for $p=3$; this agrees with the non-extensive BPS entropy on the D-brane side.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • The scaling agreement is insensitive to the mode count, so the real test of the proposal is the coefficient: a first-principles finite-temperature computation of the D3-brane worldvolume theory should decide whether the effective light-mode count is six, eight, or something else.
  • If six is correct, it is an indirect clue about which worldvolume degrees of freedom survive at the temperatures where the supergravity description applies, possibly pointing to a topological or confining phase of the gauge theory rather than a free gas of all modes.
  • The $g$-independent Hawking temperature gives a concrete weak-coupling target: a string-amplitude calculation of the decay of an excited D3-brane should reproduce the same temperature and, if the identification is right, the same entropy coefficient.
  • Because the paper expects the comparison to fail for $p<3$ when the string coupling grows near the brane, mapping where the $p=3$ agreement breaks down would delineate the domain where horizon area is a reliable microstate counter.
Original abstract

We consider slightly non-extremal black 3-branes of type IIB supergravity and show that their Bekenstein-Hawking entropy agrees, up to a mysterious factor, with an entropy derived by counting non-BPS excitations of the Dirichlet 3-brane. These excitations are described in terms of the statistical mechanics of a 3+1 dimensional gas of massless open string states. This is essentially the classic problem of blackbody radiation. The blackbody temperature is related to the temperature of the Hawking radiation. We also construct a solution of type IIB supergravity describing a 3-brane with a finite density of longitudinal momentum. For extremal momentum-carrying 3-branes the horizon area vanishes. This is in agreement with the fact that the BPS entropy of the momentum-carrying Dirichlet 3-branes is not an extensive quantity.

The compiled record

The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.

Compiled by classifier-1.13-20260917 via OpenRouter, question bank abstract-p1-20260923, 2026-09-23: 1 request, 5,526 input tokens, $0.0002 reported.

What the abstract itself states, as probabilities: claims first 0.03 · states limitation 0.89 · human participants 0.01 · controlled comparison 0.03 · randomized assignment 0.01 · states quantitative result 0.12 · compares with prior results 0.84 · mentions code or data availability 0.01.

The abstract, sentence by sentence

arXiv listing abstract v3. Results and the main claim are underlined; .

We consider slightly non-extremal black 3-branes of type IIB supergravity and show that their Bekenstein-Hawking entropy agrees, up to a mysterious factor, with an entropy derived by counting non-BPS excitations of the Dirichlet 3-brane. These excitations are described in terms of the statistical mechanics of a 3+1 dimensional gas of massless open string states. This is essentially the classic problem of blackbody radiation. The blackbody temperature is related to the temperature of the Hawking radiation. We also construct a solution of type IIB supergravity describing a 3-brane with a finite density of longitudinal momentum. For extremal momentum-carrying 3-branes the horizon area vanishes. This is in agreement with the fact that the BPS entropy of the momentum-carrying Dirichlet 3-branes is not an extensive quantity.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#sentencerolethe authors' own workstates the main conclusionstrength
s0 We consider slightly non-extremal black 3-branes of type IIB supergravity and show that their Bekenstein-Hawking entropy agrees, up to a mysterious factor, with an entropy derived by counting non-BPS excitations of the Dirichlet 3-brane. result 0.69 0.93 0.79 asserted 1.00
s1 These excitations are described in terms of the statistical mechanics of a 3+1 dimensional gas of massless open string states. method 0.80 0.45 0.06 asserted 1.00
s2 This is essentially the classic problem of blackbody radiation. background 0.78 0.09 0.03 asserted 0.99
s3 The blackbody temperature is related to the temperature of the Hawking radiation. interpretation 0.32 0.24 0.05 asserted 1.00
s4 We also construct a solution of type IIB supergravity describing a 3-brane with a finite density of longitudinal momentum. contribution 0.98 0.94 0.07 asserted 1.00
s5 For extremal momentum-carrying 3-branes the horizon area vanishes. result 1.00 0.71 0.08 asserted 1.00
s6 This is in agreement with the fact that the BPS entropy of the momentum-carrying Dirichlet 3-branes is not an extensive quantity. interpretation 0.89 0.40 0.11 asserted 0.60

What kind of paper the classifier reports this is: theoretical result 1.00 · evidence from proof or derivation 1.00.

What was examined, and what was not

sources read
  • arXiv listing abstract v3
not examined
  • full text
  • figures and tables
  • references and citing sentences
  • relations to other papers
levels run
  • P abstract
not run
  • S sections
  • T body sentences
  • C citations
  • R cross-paper relations

Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

References
How later papers used it

124 later papers cite it

Evidence: substantial. 121 of the citing papers share no author with it, and 26 of those carry a confident label from Pith's citation classifier.

Pith read 28 of the 145 citing sentences, choosing only those whose citation markers point at this paper alone, and wrote the paraphrases from them. The summary, the counts, the evidence level, the links and the quotes come from code; the summary counts the papers listed below. A later paper is listed under a label when Pith's citation classifier gives one of its sentences that label at probability 0.8 or more (0.95 for support), Pith's reading finds that the citing paper itself did it, and a second check confirms the paraphrase against the sentence. This section lists uses only. It does not list criticism or disagreement, so their absence here says nothing about how the paper has been received. Papers that share an author with this one are listed apart, under "By the same authors". A quote is the citing authors' own sentence, shown when their paper's licence is CC BY, CC BY-SA or CC0. JSON

Uses its data or values 3 of 10 papers with this label
How the literature uses it

121 arXiv papers cite this in 142 sentences

Each citing sentence is taken from the citing paper's LaTeX source and typed by Pith's classifier. A label appears at probability 0.8 or more (0.95 for support), a contest at 0.7 or more; the quoted words are the citing authors'. How each label was checked · JSON

Papers citing it · 85 sentences without a confident label

Contests it 1 paper
  • Even though the framework proposed in [ref] can not be consistently implemented within a supergravity approximation of the string theory dual to $=4$ supersymmetric Yang-Mills (SYM) plasma in the Bjorken flow [ref] (see [ref] ), if correctly reproduces the equilibrium and near-equilibrium properties of the $=4$ SYM plasma obtained from the equilibrium correlation functions, , the equilibrium equation of state [ref] , its shear viscosity at infinite 't Hooft coupling [ref] , and its relaxation time[Related work appeared in [ref] .] [ref] .

    Shear viscosity of boost invariant plasma at finite coupling · Introduction · contest 0.79

Builds on it 1 paper
Uses its method or tool 1 paper
  • In the large 't Hooft coupling limit, $λ_4 ≫1$, the entropy density can be calculated from the Bekenstein-Hawking entropy [ref] of non-extremal D3-branes with Ramond-Ramond charge (RR-charge) $N_c$, which is [ref] [equation] where $T$ is identified with the Hawking temperature of the black brane.

    AdS/CFT aspects of the cosmological QCD phase transition · $𝒩 = 4$ SYM theory · 0.86

Uses its data or values 10 papers
Compares with it 13 papers
Cites it as background 30 papers
  • In more detail, the starting point for the classic derivation of AdS/CFT is the statement [ref] that [equation] and Maldacena's low-energy/near-horizon limit transmutes this equivalence into[Here we write AdS$_p+2×$S$^8-p$ as a metonym for the conformally-related [ref] near-horizon geometry of the RR black $p$-brane [ref] , Eq. ([ref]).

    On the Underlying Nonrelativistic Nature of Relativistic Holography · Nonrelativity in Relativistic Holography · 0.92

  • Supergravity models provided a new way of understanding the unexpected “$3/4×$SB” entropy law [ref] that appears to explain numerical lattice QCD data above $T_c$ and the unexpected low viscosity of SQGP [ref] determined from collective elliptic flow data.

    Conical Di-jet Correlations from a Chromo-Viscous Neck in AdS/CFT · Introduction · 0.82

  • The lessons learned from applying the AdS/CFT correspondence [ref] to the plasma phase of strongly coupled non-abelian gauge theories [ref] played a major role (see [ref] for a recent review).

    Anomaly induced transport coefficients, from weak to strong coupling · Kubo Formulae and Holographic Triangle Anomalies · 0.90

Discussion

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