Irrational versus rational charge and statistics in two-dimensional quantum systems

Abstract

We show that quasiparticle excitations with irrational charge and irrational exchange statistics exist in tight-binding systems described, in the continuum approximation, by the Dirac equation in (2+1)-dimensional space and time. These excitations can be deconfined at zero temperature, but when they are, the charge rerationalizes to the value 1/2 and the exchange statistics to that of quartons (half-semions). © 2008 The American Physical Society.