Transport and Control in One-Dimensional Systems

TL;DR

This paper investigates magnetization transport in a Heisenberg spin chain, comparing integrable and non-integrable regimes, and explores quantum control methods to manipulate transport behavior in chaotic systems.

Contribution

It provides a comparative analysis of transport in integrable and non-integrable spin chains and demonstrates how quantum control can modify transport properties in chaotic systems.

Findings

Ballistic transport observed in integrable chains

Diffusive decay in non-integrable chains with defects

Quantum control can induce desired transport behaviors

Abstract

We study transport of local magnetization in a Heisenberg spin-1/2 chain at zero temperature. The system is initially prepared in a highly excited pure state far from equilibrium and its evolution is analyzed via exact diagonalization. Integrable and non-integrable regimes are obtained by adjusting the parameters of the Hamiltonian, which allows for the comparison of transport behaviors in both limits. In the presence of nearest neighbor interactions only, the transport behavior in the integrable clean system contrasts with the chaotic chain with on-site defects, oscillations in the first suggesting ballistic transport and a fast decay in the latter indicating diffusive transport. The results for a non-integrable system with frustration are less conclusive, similarities with the integrable chain being verified. We also show how methods of quantum control may be applied to chaotic systems to induce a desired transport behavior, such as that of an integrable system.