Maxwell's demons in multipartite quantum correlated systems

TL;DR

This paper explores how multipartite quantum correlations, quantified by thermal global quantum discord, enable a Maxwell's demon to extract more work from quantum systems than classical demons, with exact quantification for pure states.

Contribution

It introduces a protocol linking quantum correlations to work extraction advantage and demonstrates this relation using thermal global quantum discord in multipartite systems.

Findings

Quantum advantage quantified by thermal global quantum discord.

Exact quantification for pure n-partite states with Schmidt decomposition.

Upper bounds for work extraction in mixed states.

Abstract

We investigate the extraction of thermodynamic work by a Maxwell's demon in a multipartite quantum correlated system. We begin by adopting the standard model of a Maxwell's demon as a Turing machine, either in a classical or quantum setup depending on its ability of implementing classical or quantum conditional dynamics, respectively. Then, for an n-partite system (A_1, A_2, ..., A_n), we introduce a protocol of work extraction that bounds the advantage of the quantum demon over its classical counterpart through the amount of multipartite quantum correlation present in the system, as measured by a thermal version of the global quantum discord. This result is illustrated for an arbitrary n-partite pure state of qubits with Schmidt decomposition, where it is shown that the thermal global quantum discord exactly quantifies the quantum advantage. Moreover, we also consider the work extraction via mixed multipartite states, where examples of tight upper bounds can be obtained.