Four dimensional black hole microstates: from D-branes to spacetime foam

Balasubramanian, Vijay; Gimon, Eric G.; Levi, Thomas S.

doi:10.1088/1126-6708/2008/01/056

Cited by 88 publications

(140 citation statements)

References 59 publications

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“…Large classes of such smooth supergravity solutions, asymptotically indistinguishable from black hole 6 solutions, have indeed been found [7,8,9,10,11,12,13,14] (and related [15,16] to previously known black hole composites [17,18,19]). These are complete families of solutions preserving a certain amount of supersymmetry with fixed asymptotic charges 7 and with no (or very mild) singularities.…”

Section: Introductionmentioning

confidence: 79%

Black holes as effective geometries

Balasubramanian

Boer²,

El-Showk³

et al. 2008

Class. Quantum Grav.

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144

173

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Gravitational entropy arises in string theory via coarse graining over an underlying space of microstates. In this review we would like to address the question of how the classical black hole geometry itself arises as an effective or approximate description of a pure state, in a closed string theory, which semiclassical observers are unable to distinguish from the "naive" geometry. In cases with enough supersymmetry it has been possible to explicitly construct these microstates in spacetime, and understand how coarse-graining of non-singular, horizon-free objects can lead to an effective description as an extremal black hole. We discuss how these results arise for examples in Type II string theory on AdS 5 ×S 5 and on AdS 3 ×S 3 ×T 4 that preserve 16 and 8 supercharges respectively. For such a picture of black holes as effective geometries to extend to cases with finite horizon area the scale of quantum effects in gravity would have to extend well beyond the vicinity of the singularities in the effective theory. By studying examples in M-theory on AdS 3 ×S 2 ×CY that preserve 4 supersymmetries we show how this can happen. This review is a revised and extended version of proceedings submitted for the Sower's Theoretical Physics Workshop 2007 "What is String Theory?" and of lecture notes for the CERN RTN Winter School on Strings, Supergravity and Gauge Theories [1].

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Section: Introductionmentioning

confidence: 79%

Black holes as effective geometries

Balasubramanian

Boer²,

El-Showk³

et al. 2008

Class. Quantum Grav.

Self Cite

144

173

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“…In particular bubbling solutions for black holes and black rings, to be described below, were developed in [95,96,97,98,99,100,101,102,103,104]. Four charge solutions in four dimensions have been discussed in [105,106]. Non-supersymmetric solutions were found and their properties explored in [107,108,109].…”

Section: Horizon-less Limits Of Known Black Hole Solutionsmentioning

confidence: 99%

“…We now turn our attention to the main class of fuzzball geometries which have been constructed, the so-called bubbling solutions [95,96,97,98,99,100,101,102,103,104,106].…”

Section: Bubbling Geometriesmentioning

confidence: 99%

The fuzzball proposal for black holes

2008

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The fuzzball proposal states that associated with a black hole of entropy S there are exp S horizon-free non-singular solutions that asymptotically look like the black hole but generically differ from the black hole up to the horizon scale. These solutions, the fuzzballs, are considered to be the black hole microstates while the original black hole represents the average description of the system. The purpose of this report is to review current evidence for the fuzzball proposal, emphasizing the use of AdS/CFT methods in developing and testing the proposal. In particular, we discuss the status of the proposal for 2 and 3 charge black holes in the D1-D5 system, presenting new derivations and streamlining the discussion of their properties. Results to date support the fuzzball proposal but further progress is likely to require going beyond the supergravity approximation and sharpening the definition of a "stringy fuzzball". We outline how the fuzzball proposal could resolve longstanding issues in black hole physics, such as Hawking radiation and information loss.Our emphasis throughout is on connecting different developments and identifying open problems and directions for future research.

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“…Then we can regard the fact that its entropy (76) and absorption cross section (86) agree with that of a black hole as just an observation that helps us estimate the excitation probabilities in a convenient way; the brane bound state is a normal physical system like any other detector. Second, we have learnt that even if we increase the coupling to the point where the n 1 , n 5 , n p charges should give a black hole, we actually get a "fuzzball" rather than a traditional black hole with horizon [11][12][13][14][15][16][17][18][19]. A fuzzball is again just like a normal physical system, and while the information is densely packaged into its detailed structure, it is certainly extractable in principle, given that we have an arbitrary amount of time at our disposal to extract this information when we bring the system back to infinity.…”

Section: Commentsmentioning

confidence: 99%

“…Some have argued that matter never falls into black holes because of its ever increasing redshift [8], or that the backreaction of Hawking radiation may be severe enough to prevent a shell from falling through its horizon [9,10]. In string theory one finds that black hole microstates do not have regular horizons; instead they are "fuzzballs" [11][12][13][14][15][16][17][18][19]. In such situations, one may think that the information in an infalling bit would be preserved until the infalling object reaches the horizon (or the surface of the fuzzball).…”

Section: Introductionmentioning

confidence: 99%

Losing Information Outside the Horizon

Mathur

2015

Entropy

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Suppose we allow a system to fall freely from infinity to a point near (but not beyond) the horizon of a black hole. We note that in a sense the information in the system is already lost to an observer at infinity. Once the system is too close to the horizon it does not have enough energy to send its information back because the information carrying quanta would get redshifted to a point where they get confused with Hawking radiation. If one attempts to turn the infalling system around and bring it back to infinity for observation then it will experience Unruh radiation from the required acceleration. This radiation can excite the bits in the system carrying the information, thus reducing the fidelity of this information. We find the radius where the information is essentially lost in this way, noting that this radius depends on the energy gap (and coupling) of the system. We look for some universality by using the highly degenerate BPS ground states of a quantum gravity theory (string theory) as our information storage device. For such systems one finds that the critical distance to the horizon set by Unruh radiation is the geometric mean of the black hole radius and the radius of the extremal hole with quantum numbers of the BPS bound state. Overall, the results suggest that information in gravity theories should be regarded not as a quantity contained in a system, but in terms of how much of this information is accessible to another observer.

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Four dimensional black hole microstates: from D-branes to spacetime foam

Cited by 88 publications

References 59 publications

Black holes as effective geometries

Black holes as effective geometries

The fuzzball proposal for black holes

Losing Information Outside the Horizon

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