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AdS/CFT Duals of Topological Black Holes and the Entropy of Zero-Energy States

High Energy Physics - Theory · Submitted 4 Jun 1999 · 40 references

Pith's verdict: A useful, honest paper whose headline reading rests on an unproven protection argument the author himself flags.

T0 · AI review

How this review was made: An AI referee (selfhosted/deepseek-v4.1-flash) read the paper on October 29, 2026 and answered a fixed list of questions about it. T0 is the starting level every paper gets. The levels describe how deeply Pith has checked the paper, never the authors.

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  5. T4 Proof Those claims proved, and the proof checked by computer.

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arXiv IDhep-th/9906040 (version 2)
Pith IDJMVFSV36, Pith's permanent record of this paper and its review
CitationRoberto Emparan. "AdS/CFT Duals of Topological Black Holes and the Entropy of Zero-Energy States." arXiv:hep-th/9906040 (1999). https://pith.science/paper/JMVFSV36
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Claim paper

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Referee report
The paper

The paper claims

Hyperbolic black holes in anti-de Sitter space suggest that strongly coupled Super-Yang-Mills theory carries states that add entropy without adding energy, including a zero-temperature ground state with large degeneracy.

The reading

Static black holes in anti-de Sitter space can have spherical, planar, or hyperbolic horizons. The first two have been used heavily to test the AdS/CFT correspondence; the third has been comparatively neglected. This paper works out the hyperbolic case in detail, computing the dual field theory's stress tensor and entropy at both weak coupling (one-loop free fields on $S^1$ times a three-dimensional hyperboloid) and strong coupling (the black hole side), and comparing them state by state. The payoff is a set of mismatches that are hard to explain away: a state with zero temperature and zero energy density that nonetheless has large entropy, and a state whose energy agrees exactly at weak and strong coupling while its entropy is $3/2$ times larger at strong coupling. If the author is right, the dual gauge theory must contain states that store entropy but contribute nothing to the local energy density.

What carries the argument

The machinery is a three-way comparison. On the gravity side, the paper uses the counterterm-subtraction prescription for the quasilocal stress tensor of asymptotically AdS solutions, which yields $⟨T_{μν}⟩$, the energy $E(β)$ and the entropy $S(β)$ for the hyperbolic black hole family as functions of the horizon radius, with the pure-AdS member sitting at $β=2πl$ and the extremal member at $β→∞$. On the field theory side, it uses the Plancherel measure for the wave operator on hyperbolic space to compute one-loop energy and entropy densities for fields of spin 0, $1/2$ and $1$ on $S^1 × H^3$, then specializes to the $N=4$ supermultiplet content. The comparison is made meaningful by the fact that the $β=2πl$ state is conformally flat and its energy is fixed by the central charge, so both regimes can be trusted there. A conformal transformation between the hyperboloid and Rindler space then reinterprets the whole comparison as a statement about accelerating observers in flat space.

Extended reading notes

Core claim

The central claim is that hyperbolic black holes expose a genuine strong-coupling surprise in $N=4$ Super-Yang-Mills on a hyperboloid. Two states carry the argument. First, the extremal hyperbolic black hole has a stress tensor that vanishes identically, so its energy density is zero, yet its Bekenstein-Hawking entropy is nonzero; the author identifies this with a highly degenerate ground state at infinite 't Hooft coupling, in contrast to the free-field result of zero entropy. Second, the solution that is locally isometric to pure $AdS_5$ (temperature $1/(2πl)$) has an energy that matches the one-loop field theory value exactly, but an entropy larger than the weak-coupling value by a factor of $3/2$. The author stresses that the pattern is the same in both cases: entropy is enhanced at strong coupling while the energy is not, so the strong-coupling theory appears to have more states contributing to entropy than to energy. He also shows that hyperbolic black holes are, in the flat-space description of the dual theory, thermal Rindler states, so the same statements become claims about the degeneracy of the Rindler vacuum and about entanglement entropy across a Rindler horizon in exact $AdS_5$.

Load-bearing premise

The claim that the $β=2πl$ entropy mismatch is a real strong-coupling effect rests on the assumption that all string $α'$ corrections can be written in a scheme built from the Weyl tensor, so that the conformally flat pure-AdS solution is uncorrected and its free energy is protected; the author calls this reasonable rather than established, and it conflicts with a background-subtraction calculation in which that same state is corrected.

Editorial extensions

If this is right

  • At infinite 't Hooft coupling the ground state of the theory on a hyperboloid is highly degenerate even though its energy density vanishes, so the usual identification of zero energy with a unique vacuum fails in this sector.
  • The entropy of the $β=2πl$ state is $3/2$ times the one-loop value while its energy and specific heat agree exactly, which points to states that contribute to entropy but not to the stress tensor.
  • Because hyperbolic black holes are thermal Rindler states of the flat-space dual, the mismatch becomes a statement that the Minkowski vacuum, as seen by an accelerating observer, has more entanglement entropy in the strong-coupling description than free-field counting suggests.
  • The ratio $S/E$ at strong coupling exceeds the weak-coupling ratio at every finite temperature, with equality only in the infinite-temperature limit.
  • In the $AdS_4$ and $AdS_7$ cases the mismatch is sharper still: the state isometric to $AdS_4$ has finite temperature and nonzero entropy but zero energy density, and there are states of negative total energy.
  • The author notes that the required hidden degrees of freedom resemble the 'precursor' states postulated elsewhere to preserve causality in AdS/CFT scattering, suggesting a common origin.

Reading between the lines

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

  • If states carrying entropy but no local energy really exist in the gauge theory, they should show up as an anomalous contribution to the free energy on $S^1 × H^3$ that is invisible in the stress tensor; a direct resummation or lattice-style check of the one-loop result beyond leading order would be the natural place to look.
  • The $3/2$ factor is numerically the reciprocal of the familiar $3/4$ reduction seen for planar black holes, which suggests the two discrepancies may be two faces of one coupling-dependent reweighting of degrees of freedom rather than two separate puzzles.
  • Because the argument for protection relies on the solution being conformally flat, any state with a nonzero Weyl tensor should show ordinary coupling dependence; comparing the size of the $β=2πl$ anomaly with the known $α'^3$ corrections at nearby temperatures would test whether the effect is a threshold jump or a smooth drift.
  • The Rindler reformulation makes the claim in principle accessible to entanglement-entropy calculations in the field theory itself, independent of any black hole background, which is a cleaner setting in which to confirm or refute the enhancement.
Original abstract

The horizon of a static black hole in Anti-deSitter space can be spherical, planar, or hyperbolic. The microscopic dynamics of the first two classes of black holes have been extensively discussed recently within the context of the AdS/CFT correspondence. We argue that hyperbolic black holes introduce new and fruitful features in this respect, allowing for more detailed comparisons between the weak and strong coupling regimes. In particular, by focussing on the stress tensor and entropy of some particular states, we identify unexpected increases in the entropy of Super-Yang-Mills theory at strong coupling that are not accompanied by increases in the energy. We describe a highly degenerate state at zero temperature and zero energy density. We also find that the entanglement entropy across a Rindler horizon in exact AdS_5 is larger than might have been expected from the dual SYM theory. Besides, we show that hyperbolic black holes can be described as thermal Rindler states of the dual conformal field theory in flat space.

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, 5,594 input tokens, $0.0002 reported.

What the abstract itself states, as probabilities: claims first 0.07 · states limitation 0.09 · human participants 0.01 · controlled comparison 0.10 · randomized assignment 0.01 · states quantitative result 0.10 · compares with prior results 0.61 · mentions code or data availability 0.01.

The abstract, sentence by sentence

arXiv listing abstract v2. Results and the main claim are underlined; .

The horizon of a static black hole in Anti-deSitter space can be spherical, planar, or hyperbolic. The microscopic dynamics of the first two classes of black holes have been extensively discussed recently within the context of the AdS/CFT correspondence. We argue that hyperbolic black holes introduce new and fruitful features in this respect, allowing for more detailed comparisons between the weak and strong coupling regimes. In particular, by focussing on the stress tensor and entropy of some particular states, we identify unexpected increases in the entropy of Super-Yang-Mills theory at strong coupling that are not accompanied by increases in the energy. We describe a highly degenerate state at zero temperature and zero energy density. We also find that the entanglement entropy across a Rindler horizon in exact AdS_5 is larger than might have been expected from the dual SYM theory. Besides, we show that hyperbolic black holes can be described as thermal Rindler states of the dual conformal field theory in flat space.

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 The horizon of a static black hole in Anti-deSitter space can be spherical, planar, or hyperbolic. background 1.00 0.06 0.02 asserted 1.00
s1 The microscopic dynamics of the first two classes of black holes have been extensively discussed recently within the context of the AdS/CFT correspondence. background 0.99 0.04 0.02 asserted 1.00
s2 We argue that hyperbolic black holes introduce new and fruitful features in this respect, allowing for more detailed comparisons between the weak and strong coupling regimes. contribution 0.75 0.27 0.27 asserted 0.75
s3 In particular, by focussing on the stress tensor and entropy of some particular states, we identify unexpected increases in the entropy of Super-Yang-Mills theory at strong coupling that are not accompanied by increases in the energy. result 0.98 0.95 0.51 asserted 1.00
s4 We describe a highly degenerate state at zero temperature and zero energy density. result 0.95 0.93 0.14 asserted 1.00
s5 We also find that the entanglement entropy across a Rindler horizon in exact AdS_5 is larger than might have been expected from the dual SYM theory. result 1.00 0.94 0.08 asserted 0.93
s6 Besides, we show that hyperbolic black holes can be described as thermal Rindler states of the dual conformal field theory in flat space. result 0.87 0.92 0.23 asserted 1.00

What kind of paper the classifier reports this is: theoretical result 0.99 · evidence from proof or derivation 0.74.

What was examined, and what was not

sources read
  • arXiv listing abstract v2
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

Figures
Figure 1. Regions of Anti-deSitter space covered by the para

Figures reproduced from arXiv:hep-th/9906040 by the authors.

References
How later papers used it

86 later papers cite it

Evidence: substantial. 83 of the citing papers share no author with it, and 19 of those carry a confident label from Pith's citation classifier.

Pith read 22 of the 153 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 method or tool 1 of 5 papers with this label
  • Computed the energy and entropy of this state via the AdS/CFT method of this paper.

    Holographic de Sitter Universe (2011) · 1.00 · paraphrased: the licence does not allow quoting

How the literature uses it

77 arXiv papers cite this in 141 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 · 98 sentences without a confident label

Builds on it 2 papers
  • The analysis of [ref] was done only for uncharged hyperbolic black holes, but the main conclusions relevant for our purposes extend to the charged case.

    Black funnels and droplets in thermal equilibrium · Holographic interpretation of black droplets and funnels · 0.90

  • One can also study the string in the hyperbolic AdS black hole (which generalizes [ref] by replacing $-1+r^2/ℓ^2→-1+μ/r^d-1+r^2/ℓ^2$ [ref] ; for $μ≠0$ this describes the exterior of a true black hole with non-zero mass and a singularity at $r=0$), which is dual to a stationary quark in $ℝ×H^d-1$ at finite temperature.

    Chaos and the reparametrization mode on the AdS$_2$ string · Discussion · 0.96

Uses its method or tool 4 papers
  • We now compute the energy and entropy of this state via AdS/CFT method [ref] - [ref] .

    Holographic de Sitter Universe · Holographic Static de Sitter · 1.00

  • The $n$-th Rényi entropy is obtained by extending the periodicity to $τ∼τ+ 2πn$, which in the bulk corresponds to replacing $f(ζ)$ by the topological black hole [ref]

    Nonlocal Nonstabilizerness from Holographic Schwinger Pair Production · Casini–Huerta–Myers (CHM) map and topological black holes · 0.89

  • The states $|Ψ_β⟩$ for free conformal field theories can be obtained by first solving for the thermal state of the field in $ℝ×H_n-1$, which can be done with spectral methods, and then Weyl-transforming to Rindler space [ref] .

    Tearing down spacetime with quantum disentanglement · Rindler entanglement for free conformal fields · 0.96

Uses its data or values 1 paper
  • First of all note that the boundary stress tensor for the hyperbolic black hole hypbh has been previously determined in [ref] :

    Holographic models of de Sitter QFTs · Higher-dimensional conformal field theories on de Sitter spacetime. · 0.89

Compares with it 8 papers
  • Of course, this is the same factor that appears in the usual AdS/CFT computations of the CFT at finite temperature [ref] .

    Strongly Coupled Radiation from Moving Mirrors and Holography in the Karch-Randall model · Bootstrap Domain Wall Spacetimes · 0.86

  • Comparison with [ref], taking $α' = 0$ and $β' = -1$ and thus $α= β= 1$, gives us g^(n)_ab x^a x^b = - f(r) t^2 + r^2/f(r) , ϕ = - ln(H'r) = - ln(r/ℓ) , and the corresponding AdS metric obtained via the map [ref] reads [equation] Changing coordinates to $z = ℓ/(H r)$ and $t = τ/(Hℓ)$, we obtain [equation] with [equation] which is the metric for an AdS black hole with hyperbolic horizon geometry [ref] .

    Mapping AdS to dS spaces and back · Black holes · 0.86

  • The results agree with those found in [ref] in the counterterm formalism of Balasubramanian and Kraus [ref] , but we include here some of the computational steps as done in the counterterm formalism of de Haro, Skenderis and Solodukhin [ref] , since comparison with this computation will allow a concise treatment of the nonstatic foliation in Section [ref].

    Isotropic AdS/CFT fireball · Static FRW as the conformal boundary · 0.91

Cites it as background 26 papers

Discussion

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