Hartree-Fock study of phase sensitivity in disordered rings

For a system of spinless fermions in a disordered mesoscopic ring, interact ions can give rise to an enhancement of the persistent current by orders of magnitude. The increase in the current is associated with a charge reorgan ization of the ground state. The interaction strength for which this reorga nization takes place is sample dependent and the logarithm averages over th e ensemble are not representative. In this paper we demonstrate that the Ha rtree-Fock method closely reproduces results obtained by exact diagonalizat ion. For spinless fermions subject to a short-range Coulomb repulsion U, we show that plots of phase sensitivity versus U exhibit sharp peaks associat ed with significant charge reorganization. Their positions are highly sampl e dependent and they disappear upon ensemble averaging. Having established that the Hartree-Fock method works well in one dimension, we present corres ponding results for the phase sensitivity in two coupled chains. [S0163-182 9(99)04435-5].