Heat Transport in Quantum Spin Chains: Stochastic Baths vs Quantum Trajectories

TL;DR

This paper compares two methods for modeling heat transport in quantum spin chains, using stochastic baths and quantum trajectories, to analyze heat flow in open quantum systems.

Contribution

It introduces and compares stochastic heat bath and quantum trajectories methods for studying heat conduction in quantum spin chains.

Findings

Both methods effectively model heat flow in quantum spin chains.

The stochastic bath approach operates on pure states, while quantum trajectories use density matrices.

Numerical results demonstrate the applicability of both procedures to various models.

Abstract

We discuss the problem of heat conduction in quantum spin chain models. To investigate this problem it is necessary to consider the finite open system connected to heat baths. We describe two different procedures to couple the system with the reservoirs: a model of stochastic heat baths and the quantum trajectories solution of the quantum master equation. The stochastic heat bath procedure operates on the pure wave function of the isolated system, so that it is locally and periodically collapsed to a quantum state consistent with a boundary nonequilibrium state. In contrast, the quantum trajectories procedure evaluates ensemble averages in terms of the reduced density matrix operator of the system. We apply these procedures to different models of quantum spin chains and numerically show their applicability to study the heat flow.