Comments on black holes I: the possibility of complementarity

346

593

We describe the experience of an observer falling into a black hole using the AdS/CFT correspondence. In order to do this, we reconstruct the local bulk operators measured by the observer along his trajectory outside the black hole. We then extend our construction beyond the black hole horizon. We show that this is possible because of an effective doubling of the observables in the boundary theory, when it is in a pure state that is close to the thermal state. Our construction allows us to rephrase questions about information-loss and the structure of the metric at the horizon in terms of more familiar CFT correlators. It suggests that to precisely identify black-hole microstates, the observer would need to conduct measurements to an accuracy of e −S BH . This appears to be inconsistent with the "fuzzball" proposal, and other recent proposals in which pure states in the ensemble of the black hole are represented by macroscopically distinct geometries. Furthermore, our description of the black hole interior in terms of CFT operators provides a natural realization of black hole complementarity and a method of preserving unitarity without "firewalls."

“…9 We could also do a similar analysis for the finite temperature CFT on S d−1 × time, where we would have to replace the k momenta with discrete spherical harmonic modes.…”

Section: Mode Expansion Of Thermal 2-point Functionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An infalling observer in AdS/CFT

Papadodimas

Raju

2013

346

593

“…Recently, a modern interpretation of the information-loss paradox, known as the "firewall" problem [25] (also see [9-11, 26, 27] for earlier versions and [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] for a sample of the related literature). We find the current analysis to be an essential step toward a resolution of this puzzle, but defer this discussion to future publications [46,47].…”

Section: Jhep02(2014)116mentioning

confidence: 99%

Phases of information release during black hole evaporation

Brustein

Medved

2014

In a recent article, we have shown how quantum fluctuations of the background geometry modify Hawking's density matrix for black hole (BH) radiation. Hawking's diagonal matrix picks up small off-diagonal elements whose influence becomes larger with the number of emitted particles. We have calculated the "time-of-first-bit", when the first bit of information comes out of the BH, and the "transparency time", when the rate of information release becomes order unity. We have found that the transparency time is equal to the "Page time", when the BH has lost half of its initial entropy to the radiation, in agreement with Page's results. Here, we improve our previous calculation by keeping track of the time of emission of the Hawking particles and their back-reaction on the BH. Our analysis reveals a new time scale, the radiation "coherence time", which is equal to the geometric mean of the evaporation time and the light crossing time. We find, as for our previous treatment, that the time-of-first-bit is equal to the coherence time, which is much shorter than the Page time. But the transparency time is now much later than the Page time, just one coherence time before the end of evaporation. Close to the end, when the BH is parametrically of Planckian dimensions but still large, the coherence time becomes parametrically equal to the evaporation time, thus allowing the radiation to purify. We also determine the time dependence of the entanglement entropy of the early and late-emitted radiation. This entropy is small during most of the lifetime of the BH, but our qualitative analysis suggests that it becomes parametrically maximal near the end of evaporation.

“…Over the past few years, following its sharpening using quantum information theory [2], it has become increasingly clear that in order to solve this paradox there must be new physics at the black hole horizon. There are many arguments that lead to the same conclusion, some focused on the experience of infalling observers [3][4][5][6] (see also [7]), some based on the AdS-CFT correspondence [8,9], and some based on quantizing fields at the horizon [10].…”

Section: Introductionmentioning

confidence: 99%

Non-BPS multi-bubble microstate geometries

Bena

Bossard

Katmadas

et al. 2016

Self Cite

Abstract:We construct the first smooth horizonless supergravity solutions that have two topologically-nontrivial three-cycles supported by flux, and that have the same mass and charges as a non-extremal D1-D5-P black hole. Our configurations are solutions to sixdimensional ungauged supergravity coupled to a tensor multiplet, and uplift to solutions of Type IIB supergravity. The solutions represent multi-center generalizations of the non-BPS solutions of Jejjala, Madden, Ross, and Titchener, which have over-rotating angular momenta. By adding an additional Gibbons-Hawking center, we succeed in lowering one of the two angular momenta below the cosmic censorship bound, and bringing the other very close to this bound. Our results demonstrate that it is possible to construct multi-center horizonless solutions corresponding to non-extremal black holes, and offer the prospect of ultimately establishing that finite-temperature black holes have nontrivial structure at the horizon.