Phase Structure of 1d Interacting Floquet Systems I: Abelian SPTs

TL;DR

This paper classifies one-dimensional interacting Floquet localized systems with abelian symmetry protected phases, extending the understanding of non-equilibrium quantum phases beyond static systems.

Contribution

It introduces a classification scheme for Floquet SPT phases in 1D, combining static classification with a set of twisted 1D representations of the symmetry group.

Findings

Floquet phases correspond to elements of Cl×A_G

Classification extends static SPT phases to driven systems

Framework applicable to interacting, localized systems

Abstract

Recent work suggests that a sharp definition of `phase of matter' can be given for some quantum systems out of equilibrium---first for many-body localized systems with time independent Hamiltonians and more recently for periodically driven or Floquet localized systems. In this work we propose a classification of the finite abelian symmetry protected phases of interacting Floquet localized systems in one dimension. We find that the different Floquet phases correspond to elements of $\text{Cl}\times\mathcal{A}_G$, where $\text{Cl}$ is the undriven interacting classification, and $\mathcal{A}_G$ is a set of (twisted) 1d representations of $G$. We will address symmetry broken phases in a subsequent paper.