Daemonic Ergotropy: Enhanced Work Extraction from Quantum Correlations

We investigate how the presence of quantum correlations can influence work extraction in closed quantum systems, establishing anew link between the field of quantum non-equilibrium thermodynamics and the one of quantum information theory. We considera bipartite quantum system and we show that it is possible to optimize the process of work extraction, thanks to the correlationsbetween the two parts of the system, by using an appropriate feedback protocol based on the concept of ergotropy. We prove thatthe maximum gain in the extracted work is related to the existence of quantum correlations between the two parts, quantified byeither quantum discord or, for pure states, entanglement. We then illustrate our general findings on a simple physical situationconsisting of a qubit system.