Topological Heat Transport and Symmetry-Protected Boson Currents

TL;DR

This paper investigates topological heat transport in a bosonic lattice system, revealing symmetry-protected chiral heat currents and novel dissipative phenomena, with potential experimental realizations.

Contribution

It introduces the concept of dissipative symmetry-protection for topological heat currents in open quantum systems, extending topological protection to non-equilibrium thermal transport.

Findings

Discovery of chiral edge heat currents in a bosonic Hofstadter lattice.

Identification of dissipative symmetry-protection mechanisms.

Observation of heat currents flowing opposite to temperature gradients.

Abstract

The study of non-equilibrium properties in topological systems is of practical and fundamental importance. Here, we analyze the stationary properties of a two-dimensional bosonic Hofstadter lattice coupled to two thermal baths in the quantum open-system formalism. Novel phenomena appear like chiral edge heat currents that are the out-of-equilibrium counterparts of the zero-temperature edge currents. They support a new concept of dissipative symmetry-protection, where a set of discrete symmetries protects topological heat currents, differing from the symmetry-protection devised in closed systems and zero-temperature. Remarkably, one of these currents flows opposite to the decreasing external temperature gradient. As the starting point, we consider the case of a single external reservoir already showing prominent results like thermal erasure effects and topological thermal currents. Our results are experimentally accessible with platforms like photonics systems and optical lattices.