Normal-transport behavior in finite one-dimensional chaotic quantum systems

Abstract

We investigate the transport of energy, magnetization, etc. in several finite one-dimensional (1D) quantum systems only by solving the corresponding time-dependent Schrodinger equation. We explicitly renounce any other transport analysis technique. Varying model parameters we find a sharp transition from non-normal to normal transport and a transition from integrability to chaos, i.e., from Poissonian to Wigner-like level statistics. These transitions always appear in conjunction with each other. We investigate some rather abstract ``design models'' and a ( locally perturbed) Heisenberg spin chain.