Topological bulk and edge correlations in a Kitaev model on a square lattice

Abstract We study the topological bulk and edge correlations of condensed ground state in a p -wave Kitaev model on a square lattice. It is shown that the ground state of the system has the form of the condensate of the Bardeen-Cooper-Schrieffer pair, and the topological transition is associated with the nonanalytic behavior of the pairing order parameters. A real space correlation function is proposed to characterizing the topological phase of the many-body ground state. Numerical results demonstrate that this method works well in the presence of disordered perturbation, lattice defects, or irregular boundary conditions. In addition, the real space correlation function between two edges of the system is investigated, which directly reflects the existence of topological edge modes in the many-body ground state.