Topological order of mixed states in correlated quantum many-body systems

Article

关键词: QUANTIZED HALL CONDUCTANCE;    ENTANGLEMENT ENTROPY;    PHASE;    EXCITATIONS;    REALIZATION;    INVARIANT;    BANDS;    MODEL;   

DOI  :  10.1103/PhysRevB.95.075106

来源: SCIE

【 摘 要 】

Topological order has become a new paradigm to distinguish ground states of interacting many-body systems without conventional long-range order. Here, we discuss possible extensions of this concept to density matrices describing statistical ensembles. For a large class of quasithermal states, which can be realized as thermal states of some quasilocal Hamiltonian, we generalize earlier definitions of density-matrix topology to generic many-body systems with strong correlations. We point out that the robustness of topological order, defined as a pattern of long-range entanglement, depends crucially on the perturbations under consideration. While it is intrinsically protected against local perturbations of arbitrary strength in an infinite closed quantum system, purely local perturbations can destroy topological order in open systems coupled to baths if the coupling is sufficiently strong. We discuss our classification scheme using the finite-temperature quantum Hall states and point out that the classical Hall effect can be understood as a finite-temperature topological phase.

【 授权许可】

Free