{ "id": "2005.06289", "version": "v1", "published": "2020-05-13T12:40:34.000Z", "updated": "2020-05-13T12:40:34.000Z", "title": "Sustaining a temperature difference", "authors": [ "Matteo Polettini", "Alberto Garilli" ], "comment": "Submission to SciPost", "categories": [ "cond-mat.stat-mech" ], "abstract": "We derive an expression for the minimal rate of entropy that sustains two reservoirs at different temperatures $T_0$ and $T_\\ell$. The law displays an intuitive $\\ell^{-1}$ dependency on the relative distance and a characterisic $\\log^2 (T_\\ell/T_0)$ dependency on the boundary temperatures. First we give a back-of-envelope argument based on the Fourier Law (FL) of conduction, showing that the least-dissipation profile is exponential. Then we revisit a model of a chain of oscillators, each coupled to a heat reservoir. In the limit of large damping we reobtain the exponential and squared-log behaviors, providing a self-consistent derivation of the FL. For small damping \"equipartition frustration\" leads to a well-known balistic behaviour, whose incompatibility with the FL posed a long-time challenge.", "revisions": [ { "version": "v1", "updated": "2020-05-13T12:40:34.000Z" } ], "analyses": { "keywords": [ "temperature difference", "well-known balistic behaviour", "exponential", "dependency", "boundary temperatures" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }