Talk Title: Symmetry protected topological phases: realizations in spin chains and
spin ladders Topological orders are non-symmetry breaking orders of
gapped quantum phases. In one dimension (1D), topological orders are protected
by symmetry and are called symmetry protected topological (SPT) orders. The 1D
SPT orders are classified by projective representations of the symmetry group
of the system. In this talk, we will study a specific SPT order in integer spin
models that respect D2 + T symmetry. Here D2 is a discrete spin rotation
symmetry group and T means time reversal. We show that there are totally 16
different SPT phases protected by D2 + T symmetry, all of them can be realized
in S = 1 spin chains or ladders. We show that these phases can be distinguished
by their different behaviors of `end spins'. We come up with an experimental
scenario to separate these phases. Click to download: Presentation File |