Daemonic ergotropy: enhanced work extraction from quantum correlations

By G. Francica, John Goold, F. Plastina, Mauro Paternostro. npj Quantum Information, 2016

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We investigate how the presence of quantum correlations can influence work extraction in closed quantum systems, establishing a new link between the field of quantum non-equilibrium thermodynamics and the one of quantum information theory. We consider a bipartite quantum system and we show that it is possible to optimize the process of work extraction, thanks to the correlations between the two parts of the system, by using an appropriate feedback protocol based on the concept of ergotropy. We prove that the maximum gain in the extracted work is related to the existence of quantum correlations between the two parts, quantified by either quantum discord or, for pure states, entanglement. We then illustrate our general findings on a simple physical situation consisting of a qubit system. A strong connection exists between the ability of a quantum system to perform thermodynamic work and the amount of quantum correlations that are set in its physical configuration. Here, in this manuscript, the authors have considered the problem embodied by the extraction of thermodynamic work from an elementary quantum system. They have allowed the system to be aided by an ‘‘ancilla’’, upon which measurements can be performed in the best possible way. It has been found that more work is extracted from the system when it shares quantum correlations with its ancilla, thus shedding light on a fundamental question in quantum thermodynamics: are genuine quantum resources useful for thermodynamics purposes?

Subfields: Atomic and Molecular Physics, and Optics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/bebe7292788eb5829b45e54657f822254d9a32a1