Non-Abelian Quantum Transport and Thermosqueezing Effects

TL;DR

This paper develops a theoretical framework for non-Abelian quantum transport using generalized Gibbs ensembles with non-commuting charges, revealing how quantum coherence influences dissipation and entropy production in quantum thermodynamic systems.

Contribution

It introduces a novel linear response theory for non-Abelian transport with non-commuting charges, demonstrating Onsager reciprocity and the impact of quantum coherence on entropy production.

Findings

Quantum coherence reduces net entropy production.

Transport coefficients obey Onsager reciprocity.

Thermosqueezing effects have potential applications in quantum metrology.

Abstract

Modern quantum experiments provide examples of transport with non-commuting quantities, offering a tool to understand the interplay between thermal and quantum effects. Here we set forth a theory for non-Abelian transport in the linear response regime. Our key insight is to use generalized Gibbs ensembles with non-commuting charges as the basic building blocks and strict charge-preserving unitaries in a collisional setup. The linear response framework is then built using a collisional model between two reservoirs. We show that the transport coefficients obey Onsager reciprocity. Moreover, we find that quantum coherence, associated to the non-commutativity, acts so as to reduce the net entropy production, when compared to the case of commuting transport. This therefore provides a clear connection between quantum coherent transport and dissipation. As an example, we study heat and squeezing fluxes in bosonic systems, characterizing a set of thermosqueezing coefficients with potential applications in metrology and heat-to-work conversion in the quantum regime.