Heat transport in an open transverse-field Ising chain

TL;DR

This paper investigates heat transport in an open transverse-field Ising chain, revealing ballistic, diffusive, and transition behaviors, with thermal conductivity showing temperature-dependent decay.

Contribution

It introduces a quantization method in the Fock space for weak coupling regimes and characterizes different transport regimes and transitions in the system.

Findings

Ballistic transport in uniform chains.

Normal diffusion in random-exchange chains.

Transition from ballistic to diffusive transport at intermediate disorder.

Abstract

The heat conduction in an open transverse-field Ising chain is studied by using quantization in the Fock space of operators in the weak coupling regimes, i.e. the coupling is much smaller than the transverse field. The non-equilibrium steady state is obtained for large size systems coupled to Markovian baths at its ends. The ballistic transport is observed in the uniform chain and normal diffusion in the random-exchange chain. {In addition, the ballistic-diffusive transition is found at the intermediate disorder regime.} The thermal conductivity $\kappa$ is also calculated in the low and high temperature regimes. It is shown that $\kappa$ decays as $\kappa\sim T^{-2}$ at high temperatures.