Non-thermal quantum channels as a thermodynamical resource

TL;DR

This paper investigates how non-thermal quantum channels can be used as resources in quantum thermodynamics to maximize work extraction, providing formulas and bounds for different types of channels and applying them to collapse models.

Contribution

It introduces a framework for quantifying the work extractable from non-thermal quantum channels within thermodynamic resource theory, including additive formulas and bounds.

Findings

Distillable work is additive for multiple channel uses.

Formulas are provided for finite-dimensional and bosonic channels.

Collapse models predict minimal work extraction from vacuum, with very low power.

Abstract

Quantum thermodynamics can be understood as a resource theory, whereby thermal states are free and the only allowed operations are unitary transformations commuting with the total Hamiltonian of the system. Previous literature on the subject has just focused on transformations between different state resources, overlooking the fact that quantum operations which do not commute with the total energy also constitute a potentially valuable resource. In this Letter, given a number of non-thermal quantum channels, we study the problem of how to integrate them in a thermal engine so as to distill a maximum amount of work. We find that, in the limit of asymptotically many uses of each channel, the distillable work is an additive function of the considered channels, computable for both finite dimensional quantum operations and bosonic channels. We apply our results to bound the amount of distillable work due to the natural non-thermal processes postulated in the Ghirardi-Rimini-Weber (GRW) collapse model. We find that, although GRW theory predicts the possibility to extract work from the vacuum at no cost, the power which a \emph{collapse engine} could in principle generate is extremely low.