CCQ Seminar: Philipp Dumitrescu

Wednesday Apr 1, 2020, 12:00 PM → 1:00 PM America/New_York

Title: Phases of matter and time-translation symmetries in quasiperiodically driven systems

Abstract: Conventionally, we think of phases of matter in terms of Hamiltonians and their corresponding ground states or equilibrium distributions. Driving a system out of equilibrium leads to many new physical regimes and phenomena. Excitingly, driving can enable symmetry broken phases and topological phases that are impossible in equilibrium.

Understanding the interplay of dynamical stability (heating) and phases of matter in periodically driven `Floquet' systems has received a lot of attention in the last years, which I will summarize.

Then I will generalize the discussion to quasiperiodically driven, which we have studied recently. Here the drive consists of two or more incommensurate frequencies and many of the tools of Floquet theory break down.  We show that these have a well-defined notion of  multiple time-translational symmetries (TTSes). These can be used to define many new phases of matter protected by these TTSes not realizable in a static or Floquet setting. We develop new techniques to address the stability of these interacting phases in the prethermal regime.