Quantum thermodynamics with local control

TL;DR

This paper explores the fundamental limits of quantum thermodynamic processes when only local control over many-body systems is available, revealing constraints on efficiency and work extraction, especially in the 1D Ising model.

Contribution

It introduces a framework for analyzing thermodynamic tasks with restricted local control, highlighting novel bounds and efficiency limitations in quantum many-body systems.

Findings

Local control limitations prevent reaching Carnot efficiency in general.

Strong interactions in the ferromagnetic case hinder work extraction.

Anti-ferromagnetic interactions can approach Carnot efficiency with increasing coupling strength.

Abstract

We investigate the limitations that emerge in thermodynamic tasks as a result of having local control only over the components of a thermal machine. These limitations are particularly relevant for devices composed of interacting many-body systems. Specifically, we study protocols of work extraction that employ a many-body system as a working medium whose evolution can be driven by tuning the on-site Hamiltonian terms. This provides a restricted set of thermodynamic operations, giving rise to novel bounds for the performance of engines. Our findings show that those limitations in control render it in general impossible to reach Carnot efficiency; in its extreme ramification it can even forbid to reach a finite efficiency of work per particle. We focus on the 1D Ising model in the thermodynamic limit as a case study. We show that in the limit of strong interactions the ferromagnetic case becomes useless for work extraction, while the anti-ferromagnetic improves its performance with the strength of the couplings, reaching Carnot in the limit of arbitrary strong interactions. Our results provide a promising connection between the study of quantum control and thermodynamics and introduce a more realistic set of physical operations well suited to capture current experimental scenarios.