Daemonic ergotropy: generalised measurements and multipartite settings
arXiv:1907.01970 · doi:10.3390/e21080771
The paper extends the concept of daemonic ergotropy to include generalized (POVM) measurements, introduces an algorithm to find optimal measurements for work extraction, and generalizes the framework to multipartite systems to study the role of quantum correlations.
Abstract
Recently, the concept of daemonic ergotropy has been introduced to quantify the maximum energy that can be obtained from a quantum system through an ancilla-assisted work extraction protocol based on information gain via projective measurements [G. Francica {\it et al.}, npj Quant. Inf. {\bf 3}, 12 (2018)]. We prove that quantum correlations are not advantageous over classical correlations if projective measurements are considered. We go beyond the limitations of the original definition to include generalised measurements and provide an example in which this allows for a higher daemonic ergotropy. Moreover, we propose a see-saw algorithm to find a measurement that attains the maximum work extraction. Finally, we provide a multipartite generalisation of daemonic ergotropy that pinpoints the influence of multipartite quantum correlations, and study it for multipartite entangled and classical~states.
6+3 pages, 2 figures