Speaker: Matthew Cha (UC Davis)
Title: Gapped ground state phases, topological order and anyons
Time/Date: 4:45-6:15, Wed. June 24, 2014
Abstract: The ground state of a many-body quantum system can be topologically ordered. This may be manifested through ground state degeneracy on surfaces of different genus, long range entanglement within the ground state, and, in two dimensions, quasi-particle excitations which have braided statistic. Working in the framework of quantum spin systems, we will review the notion of a gapped ground state phase and discuss the role of topological order in the stability of ground state phases. We then consider certain Hamiltonian lattice models that have quasi-particle excitations with braid statistics, these are called anyons. In the abelian case, an analysis of the superselection sectors will recover the complete particle type, fusion and braiding.