English

Work extraction and thermodynamics for individual quantum systems

Quantum Physics 2014-09-29 v2

Abstract

Thermodynamics is traditionally concerned with systems comprised of a large number of particles. Here we present a framework for extending thermodynamics to individual quantum systems, including explicitly a thermal bath and work-storage device (essentially a `weight' that can be raised or lowered). We prove that the second law of thermodynamics holds in our framework, and give a simple protocol to extract the optimal amount of work from the system, equal to its change in free energy. Our results apply to any quantum system in an arbitrary initial state, in particular including non-equilibrium situations. The optimal protocol is essentially reversible, similar to classical Carnot cycles, and indeed, we show that it can be used it to construct a quantum Carnot engine.

Keywords

Cite

@article{arxiv.1307.1558,
  title  = {Work extraction and thermodynamics for individual quantum systems},
  author = {Paul Skrzypczyk and Anthony J. Short and Sandu Popescu},
  journal= {arXiv preprint arXiv:1307.1558},
  year   = {2014}
}

Comments

11 pages, no figures. v2: published version. arXiv admin note: substantial text overlap with arXiv:1302.2811

R2 v1 2026-06-22T00:46:04.783Z