Talk Title: Topological properties of topological superconductor
and XY model under twist We use the twist boundary condition method to study the
topological properties of one dimensional XY model and its dual model ---one
dimensional superconductor. We show that there is a topological degeneracy for
the one dimensional superconductor, and relate it to the symmetry degeneracy of
XY model. Also we find level crossing for topological superconductor when one
changes the twist angle. Finally, we propose a quantized berry phase di_erence
which can describe the phase transition in XY model. |