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 $\pm π$ (modulo 2$π$), according as 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.

10 pages(LATEX) + 1 figure, (revised version). Will appear in Europhys. Lett