paper

Bulk-edge correspondence in nonunitary Floquet systems with chiral symmetry

arXiv:1609.09650 · doi:10.1103/PhysRevA.102.062202

Abstract

We study topological phases in one-dimensional open Floquet systems driven by chiral symmetric nonunitary time evolution. We derive a procedure to calculate topological numbers from nonunitary time-evolution operators with chiral symmetry. While the procedure has been applied to open Floquet systems described by nonunitary time-evolution operators, we give the microscopic foundation and clarify its validity for the first time. We construct a model of chiral symmetric nonunitary quantum walks classified into class BDI or AIII, which is one of enlarged symmetry classes for topological phases in open systems, based on experiments of discrete-time quantum walks. Then, we confirm that the topological numbers obtained from the derived procedure give correct predictions of the emergent edge states. We also show that the model retains symmetry in certain cases and its dynamics is crucially affected by the presence or absence of symmetry.

12 pages, 6 figures

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