Phase structure of one-dimensional interacting Floquet systems. II. Symmetry-broken phases

Recent work suggests that a sharp definition of ``phase of matter'' can be given for periodically driven ``Floquet'' quantum systems exhibiting many-body localization. In this work, we propose a classification of the phases of interacting Floquet localized systems with (completely) spontaneously broken symmetries; we focus on the one-dimensional case, but our results appear to generalize to higher dimensions. We find that the different Floquet phases correspond to elements of Z (G), the center of the symmetry group in question. In a previous paper C. W. von Keyserlingk and S. L. Sondhi, preceding paper, Phys. Rev. B 93, 245145 (2016), we offered a companion classification of unbroken, i. e. , paramagnetic phases.