Planckian Metals and Black Holes

ABSTRACT
Many modern materials feature a “Planckian metal”: a phase of electronic quantum matter without quasiparticle excitations, and relaxation in a time of order Planck's constant divided by the absolute temperature. The semiclassical theory of black holes predicts thermodynamic properties which are difficult to connect to a unitary quantum theory with a discrete spectrum. I will review recent progress in understanding these problems in very different fields of physics by using insights from the Sachdev-Ye-Kitaev model of many-particle quantum dynamics.
BIO
Subir Sachdev is Herchel Smith Professor of Physics at Harvard University and Maureen and John Hendricks Distinguished Visiting Professor at the Institute for Advanced Study, Princeton, specializing in condensed-matter physics. He was elected to the U.S. National Academy of Sciences in 2014 and Foreign Fellow of the Indian National Science Academy in 2019. He received the Lars Onsager Prize from the American Physical Society and the Dirac Medal from the ICTP in 2018. His research describes the connection between physical properties of modern quantum materials and the nature of quantum entanglement in the many-particle wavefunction. He has made extensive contributions to the description of the diverse varieties of entangled states of quantum matter. These include states with topological order, with and without an energy gap to excitations, and critical states without quasiparticle excitations.