The very successful theory of metals is based upon a Boltzmann equation for an electron liquid. But the “strange metals’ found in high temperature superconductors do not have well-defined electron-like excitations, which raises the problem of a theory of electrical transport in such metals. In their quantum theory of black holes, Gibbons and Hawking applied the Boltzmann statistical ensemble to the Einstein-Maxwell theory, and obtained results for black hole entropy which did not have an evident interpretation in terms of the eigenstates of a quantum Hamiltonian. I will introduce and describe these long-standing problems in two very different fields of physics, and review progress in resolving them using insights from the solvable Sachdev-Ye-Kitaev model of fermions with random interactions.

Bio

Subir Sachdev was educated at the Indian Institute of Technology, Delhi, the Massachusetts Institute of Technology, and Harvard University. He has held professional positions at Bell Labs, Yale University, and Harvard where he is now the Herchel Smith Professor of Physics. During 2021-22 he is also the Maureen and John Hendricks Distinguished Visiting Professor at The Institute for Advanced Study, Princeton.

He has been elected to national academies of science in India and the U.S. and is a recipient of a number of awards and honors which include the Dirac Medal from the International Center for Theoretical Physics, and the Lars Onsager Prize from the American Physical Society,