Regensburg 2016 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 17: Statistical Physics far from Thermal Equilibrium

DY 17.8: Vortrag

Dienstag, 8. März 2016, 12:00–12:15, H48

Defining work from operational principles — •Rodrigo Gallego, Jens Eisert, and Henrik Wilming — Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, 14195 Berlin, Germany

In recent years we have witnessed a concentrated effort to make sense of thermodynamics for small-scale systems. One of the main difficulties is that, at the nano-scale, thermal fluctuations of energy in general render it conceptually difficult to distinguish work from heat. Despite of several attempts to resolve this issue, many of which inspired by quantum information theory, there is still remarkable little consensus on it. In this work, we attempt to define work in a strictly operational way. In our resource-theoretic approach, agents wish to agree upon how much work needs to be invested to effect a transition from one state of an arbitrary quantum work-storage device to another. We introduce basic operational principles, and deduce from them a strict set of mathematical properties that any reasonable function quantifying such work has to fulfill. We show that one work quantifier satisfying all the required properties is the difference of the non-equilibrium free energy of the initial and final state of the work-storage system. More generally, for any work quantifier fulfilling the stated properties, we can derive a quantitative second law in the sense of bounding the work that can be performed using some non-equilibrium resource by the work that is needed to create it. We furthermore discuss the role of path dependence for work quantifiers and the connection to the concept of probability-distributions of work.