Since 2002 Perimeter Institute has been recording seminars, conference talks, and public outreach events using video cameras installed in our lecture theatres. Perimeter now has 7 formal presentation spaces for its many scientific conferences, seminars, workshops and educational outreach activities, all with advanced audio-visual technical capabilities. Recordings of events in these areas are all available On-Demand from this Video Library and on Perimeter Institute Recorded Seminar Archive (PIRSA). PIRSA is a permanent, free, searchable, and citable archive of recorded seminars from relevant bodies in physics. This resource has been partially modelled after Cornell University's arXiv.org.
Condensed matter systems at ultra low-temperature that show purely quantum phenomena – even on big scales (superfluidity, superconductivity, Bose-Einstein condensates); measurements in the quantum world; probing the foundations of quantum theory.
Many aspects of geometry, black holes, novel views on the evolution of the universe (was there something before the Big Bang?), the interplay and unification of general relativity and quantum physics, and science of consciousness.
In this talk, I start with a short review of the available mechanisms for extracting energy from rotating black holes, in particular superradiance and the Blandford-Znajek process. I then describe how these mechanisms may be realized and studied via the AdS/CFT and Kerr/CFT correspondence.
We consider the problem of how fast a quantum system can scramble (thermalize) information, given that the interactions are between bounded clusters of degrees of freedom. Based on previous work, we conjecture: 1) The most rapid scramblers take a time logarithmic in the number of degrees of freedom. 2)Matrix quantum mechanics (systems whose degrees of freedom are n by n matrices) saturate the bound. 3) Black holes are the fastest scramblers in nature.
Holography is usually applied to black holes that are supersymmetric, charged, or living in higher dimensions. The astrophysical Kerr black holes that have been observed in the sky have none of these nice properties, and AdS/CFT does not apply. Nevertheless, by studying the symmetries of the near horizon region, I will show that extreme Kerr black holes are holographically dual to a two-dimensional conformal field theory. The U(1) isometry of the near horizon region extends asymptotically to a Virasoro algebra.
I'll discuss information retrieval from evaporating black holes, assuming that the internal dynamics of a black hole is unitary and rapidly mixing, and assuming that the retriever has unlimited control over the emitted Hawking radiation. If the evaporation of the black hole has already proceeded past the 'half-way' point, where half of the initial entropy has been radiated away, then additional quantum information deposited in the black hole is revealed in the Hawking radiation very rapidly.
We present new results from our Monte Carlo simulation of SUSY matrix quantum mechanics with 16 supercharges at finite temperature. The internal energy can be fitted nicely to the behavior predicted from the dual black hole thermodynamics including the alpha' corrections. The temporal Wilson loop can also be predicted from the gravity side, and it is directly related to the Schwarzschild radius of the dual black hole geometry. Our results for the Wilson loop indeed confirm this prediction up to subleading terms anticipated from the alpha' corrections on the gravity side.
I'll discuss some large N quantum mechanical theories that are toy models for eternal black holes in AdS via gauge/gravity duality. They can be used to study the classical limit and quantum corrections in gravity, and their roles in the information paradox. We demonstrate that such large N models can exhibit late time fall-off of a two-point function. By computing higher genus corrections explicitly, we argue that the fall-off, and thus information loss, persist even after perturbative gravity corrections are included.