Localization in non-Hermitian quantum mechanics and flux-line pinning in superconductors

Abstract

A recent development in studies of random non-Hermitian quantum systems is reviewed. Delocalization was found to occur under a sufficiently large constant imaginary vector potential even in one and two dimensions. The phenomenon has a physical realization as flux-line depinning in type-II superconductors. Relations between the delocalization transition and the complex energy spectrum of the non-Hermitian systems are described. Analytical and numerical results obtained for a non-Hermitian Anderson model are shown.Comment: An invited talk at StatPhys-Taipei1997 (August 1997, Taiwan). To be published in Physica A: Statistical and Mathematical Physics. 18 pages with 9 eps files embedde