Criticality in transport through the quantum Ising chain

TL;DR

This paper investigates thermal transport in a quantum Ising chain connected to reservoirs, revealing quantum phase transition signatures in steady-state energy currents at finite temperatures.

Contribution

It introduces a rate equation approach based on quasiparticle pairs to analyze non-equilibrium transport in quantum-critical systems.

Findings

Quantum phase transition signatures appear in steady-state energy currents.

Transport properties are sensitive to the quantum critical point.

Finite temperature effects do not obscure critical behavior.

Abstract

We consider thermal transport between two reservoirs coupled by a quantum Ising chain as a model for non-equilibrium physics induced in quantum-critical many-body systems. By deriving rate equations based on exact expressions for the quasiparticle pairs generated during the transport, we observe signatures of the underlying quantum phase transition in the steady-state energy current already at finite reservoir temperatures.