Incoherent transport induced by a single static impurity in a Heisenberg chain

TL;DR

This paper investigates how a single static impurity disrupts coherent transport in a Heisenberg chain, leading to incoherent behavior and diffusive transport at finite temperatures.

Contribution

It demonstrates that a single impurity breaks integrability, causing a transition from dissipationless to incoherent transport and establishing a linear relationship between relaxation time, conductivity, and chain length.

Findings

Impurity induces Wigner-Dyson level statistics.

Incoherent transport emerges at high temperatures.

Relaxation time and conductivity scale linearly with length.

Abstract

The effect of a single static impurity on the many-body states and on the spin and thermal transport in the one-dimensional anisotropic Heisenberg chain at finite temperatures is studied. Whereas the pure Heisenberg model reveals Poisson level statistics and dissipationless transport due to integrability, we show using the numerical approach that a single impurity induces Wigner-Dyson level statistics and at high enough temperature incoherent transport within the chain, whereby the relaxation time and d.c. conductivity scale linearly with length.