Geometric phase for a dimerized disordered continuum: topological shot noise

Abstract

Geometric phase shift associated with an electron propagating through a dimerized disordered continuum is shown to be 0, or ±π (modulo 2π), according to whether the associated circuit traversed in the two-dimensional parameter space excludes, or encircles a certain singularity. This phase shift is a topological invariant. Its discontinuous dependence on the electron energy and disorder implies a statistical spectral and conductance fluctuation in a corresponding mesoscopic system. Inasmuch as the fluctuation derives from the discreteness of the phase shift, it may aptly be called a topological shot noise.