Black Holes: Complementarity, Fuzz, or Fire?
Coordinators: Raphael Bousso (UCB), Samir Mathur (Ohio State), Rob Myers (Perimeter), Joe Polchinski (UCSB), Lenny Susskind (Stanford)
Scientific Advisors: Don Marolf (UCSB)
Understanding the quantum properties of black holes --- the nature of black hole entropy, and the fate of black hole information --- has been a driving problem in theoretical physics, leading in particular to the discovery of AdS/CFT duality. This duality implies that quantum mechanics is unmodified and information is not lost. However, important questions remain: (1) quantum mechanics is saved by sacrificing locality, but the nature of this nonlocality is not clear; (2) AdS/CFT gives a precise construction of quantum gravity in an AdS box, but the extension to more general spacetimes is not understood; (3) the black hole interior is a toy model of a cosmology, so an understanding of the implications of the duality for the interior would be a stepping-stone to larger questions.
Ongoing developments in this area have included the fuzzball program and new ideas from quantum information theory such as black holes as fast scramblers and information mirrors. Building on these, it has recently been argued that the existing framework of black hole complementarity is inconsistent, and that an infalling observer may encounter a `firewall' rather than the expected smooth horizon. This has led to a new wave of interest, with an enlarged circle of ideas.
The purpose of this program is to bring together a broad spectrum of researchers in this area for formal and informal discussions. Topics will include: the smoothness of the horizon and the experience of the infalling observer; the relation between entanglement and the emergence of spacetime; expanded notions of black hole complementarity; the fast-scrambling conjecture; limitations on information decoding from quantum computation; the black hole final state proposal and other potential modifications of quantum mechanics; the relation between the firewall and the fuzzball program; forms of nonlocal dynamics other than black hole complementarity; lessons from AdS/CFT duality; the possibility of observable effects outside black holes or at cosmological horizons.