Anomalous flow in correlated quantum systems: No-go result and multiple-charge scenario

TL;DR

This paper investigates anomalous charge flow in correlated quantum systems, demonstrating conditions under which energy and other conserved charges can flow against gradients without initial correlations, expanding understanding of quantum thermodynamics.

Contribution

It introduces a global-local thermodynamic framework for charge exchange, analytically rules out AEF in uncorrelated energy systems, and uncovers a correlation-free AEF mechanism driven by drag effects in multiple-charge systems.

Findings

AEF is absent in uncorrelated energy-conserving systems, even with catalysts.

Multiple conserved charges can induce AEF without initial correlations.

Numerical examples confirm theoretical predictions.

Abstract

Correlated quantum systems can exhibit thermodynamic behaviors that defy classical expectations, with anomalous energy flow (AEF) against temperature gradients serving as a paradigmatic example. While AEF has been shown to arise from the consumption of initial quantum correlations, little is known about whether AEF can occur without correlation depletion, or if analogous anomalous transport exists for conserved quantities--dubbed charges--other than energy. Here, we develop a general global-local thermodynamic approach to describe charge exchange between arbitrary correlated quantum systems. For energy-conserving systems, we analytically rule out AEF in initially uncorrelated states, even with the involvement of quantum catalysts, thereby complementing existing studies. In contrast, in systems with multiple conserved charges, we uncover a mechanism for AEF that requires no initial correlations but is instead induced by a drag effect from normal flows of non-energy charges. Furthermore, by treating all conserved charges on equal footing, we generalize AEF to a broader concept of anomalous charge flow, applicable to any conserved charge. We confirm theoretical expectations with numerical examples. These findings deepen our understanding of nonequilibrium quantum thermodynamics and open new avenues for controlling transport phenomena in correlated quantum systems.