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Long-lived interacting phases of matter protected by multiple time-translation symmetries in quasiperiodically driven systems

Wednesday, February 26, 2020 - 12:00 pm
Dominic Else, Ph.D. (Massachusetts Institute of Technology)

The discrete time-translation symmetry of a periodically-driven (Floquet) system allows for the existence of novel, nonequilibrium interacting phases of matter. A well-known example is the discrete time crystal, a phase characterized by the spontaneous breaking of this time-translation symmetry. In this talk, I will show that the presence of *multiple* time-translational symmetries, realized by quasiperiodically driving a system with two or more incommensurate frequencies,  leads to a panoply of novel non-equilibrium phases of matter, both spontaneous symmetry breaking ("discrete time quasi-crystals") and topological.

In order to stabilize such phases, I will outline rigorous mathematical results establishing slow heating of systems driven quasiperiodically at high frequencies. As a byproduct, I will introduce the notion of many-body localization (MBL) in quasiperiodically driven systems.

arXiv reference: 1910.03584




Dominic received his PhD from UCSB in 2018 and is currently a postdoctoral fellow at MIT. He works on the theory of phases of matter, especially topological phases and phases of matter out of equilibrium