Correlations enable lossless ergotropy transport

TL;DR

This paper demonstrates that quantum correlations enable lossless transport of ergotropy, the work extractable from quantum batteries, even through energy-conserving channels, highlighting correlations as a valuable resource.

Contribution

It reveals that correlations can enable lossless ergotropy transport in quantum systems, a novel insight contrasting with the typical lossy nature of uncorrelated systems.

Findings

Correlations enable gainful ergotropy transport.

Lossless transport possible with certain correlated states.

Single correlated state can transfer multiple times without loss.

Abstract

"A battery powers a device" can be read as "work stored in the battery is being transported to the device." In quantum batteries, the total amount of stored work can be measured by ergotropy, which is the maximal work extractable by unitary operations. Transporting ergotropy is fundamentally different from transporting energy, and here we find that ergotropy can be gained even when the transmission channel is strictly energy conserving. We show that, generically, ergotropy transport is lossy whenever the two systems start uncorrelated. In contrast, for a large class of correlated initial states, transport can be gainful. Furthermore, a single correlated state can be used multiple times, allowing to transport without losses an order of magnitude more work than the battery capacity. Correlations are thus a useful resource for ergotropy transport, and we quantify how this resource is consumed during gainful transport.