General Physics Colloquium, Prof. Alex Maloney, McGill University

Title:  Quantum Fields, Quantum Gravity, and Black Holes

Host:  Tom Hartman

Abstract:  Black hole physics provides a powerful window onto some of the deepest and most perplexing questions in quantum field theory and quantum gravity.  This can be made precise using the AdS/CFT correspondence, which relates theories of quantum gravity to conformal field theories (CFTs) in one less dimension.  These CFTs are similar to the gauge theories which describe the fundamental forces of particle physics, as well as to those which describe important statistical and condensed matter systems at criticality.  In studying this correspondence, we have made a surprising discovery: the simplest theories of gravity are related to field theories where the coupling constants are essentially random variables, much like in a spin glass or other disordered system.  This has allowed us to answer one of the longest standing problems in theoretical physics –  what is quantum gravity? – in certain simple, solvable cases.  In answering this question, we have discovered a remarkable relationship between the microscopic physics of black holes and quantum chaos, and opened up new perspectives onto the relationship between the space-time, quantum information theory, and statistical mechanics.