Abstract:
Many-body localization (MBL) is Anderson localization of many interacting quantum degrees of freedom in highly-excited states at conditions that correspond to a nonzero entropy density at thermal equilibrium.
The opposite of MBL is thermalization, where the isolated quantum many-body system successfully acts as a thermal bath for itself, bringing all of its small subsystems to thermal equilibrium with each other via the unitary quantum dynamics of the closed system.
For finite systems with short-range interactions the transition from thermalization to MBL occurs in two stages as the interactions are reduced: First is a smooth crossover to a “glassy” prethermal MBL regime, where the thermalization time of a large system becomes extremely large but not infinite.
Then, at still weaker interaction is the dynamical phase transition in to the MBL phase, which in many cases occurs at a strength of interactions that is so small that it is thermodynamically insignificant in the limit of large systems, even though it has strong long-time dynamical effects.
Bio:
Ph.D. in theoretical physics from Cornell University, 1983, Michael E Fisher, thesis advisor. Research staff at Bell Laboratories 1983-1996, then professor of physics at Princeton University 1996-. Some honors: member of National Academy of Science; Lars Onsager Prize of American Physical Society 2022. Topics of noted works: Spin glasses, vortices in superconductors, many-body quantum dynamics.