Title: "Electrons at finite temperature"

So Hirata, Marvin T. Schmidt Professor
Department of Chemistry, University of Illinois at Urbana-Champaign

Host: Mark Gordon

Abstract: Ab initio electronic structure theory has transformed gas-phase molecular sciences with its predictive abilities. To bring such predictive abilities to macroscopic systems and condensed matter, the theory must integrate quantum mechanics and statistical thermodynamics, so that thermodynamic functions such as free energy, internal energy, entropy, and chemical potentials are computed as functions of temperature in a systematically converging series of approximations. I will present a plain and reliable (if tedious) algebraic method of derivation of finite-temperature many-body perturbation theory for electrons, deriving its grand potential, chemical potential, and internal energy formulas at any arbitrary perturbation orders, and then stipulate its diagrammatic rules and prove a linked-diagram theorem. I will also analyze the root cause of the 60-plus-year-old controversy or confusion known as the Kohn–Luttinger nonconvergence problem and offer a simple, practical solution.

Bio: So Hirata is the Marvin T. Schmidt Professor of Chemistry at University of Illinois at Urbana−Champaign. Previously, he was Assistant Professor, then Associate Professor of Chemistry and Physics at the Quantum Theory Project, University of Florida, following his appointment as Senior Research Scientist at Pacific Northwest National Laboratory. He earned his B.S. and M.S. from The University of Tokyo and Ph.D. from The Graduate University for Advanced Studies (Institute for Molecular Science) all in chemistry. He is an elected member of the International Academy of Quantum Molecular Science. He specializes in quantum many-body theory for chemistry.