Condensed Matter Physics Seminars
Stony Brook University
Topological phases in driven systems and quantum information flow
It has recently been realized that there exist strongly disordered `many-body localized' (MBL) quantum systems, which fail to thermalize their subsystems. Their excited states can then share the same qualitative properties as the ground state, including area law entanglement, making it possible to realize exotic topological orders at finite energy density. Here we will discuss the driven (or `Floquet') version of such MBL systems, where even more exotic phases, having no equilibrium analogues, can be realized. These novel phases are characterized by chiral transport along their edges. However, since there are no conserved quantities, including energy, in these systems, it is difficult to determine what is being transported. Here we will provide a formula for a quantized invariant, first introduced by Gross, Nesme, Vogts, and Werner, that describes quantum information being transported in a chiral fashion at the edges of these systems.