{ "id": "cond-mat/0304251", "version": "v2", "published": "2003-04-10T22:02:05.000Z", "updated": "2003-06-25T18:50:36.000Z", "title": "On the (Boltzmann) Entropy of Nonequilibrium Systems", "authors": [ "S. Goldstein", "Joel L. Lebowitz" ], "comment": "31 pages, in Tex, authors' e-mails: oldstein@math.rutgers.edu, lebowitz@math.rutgers.edu", "journal": "Physica D193 (2004) 53-66", "doi": "10.1016/j.physd.2004.01.008", "categories": [ "cond-mat.stat-mech", "astro-ph" ], "abstract": "Boltzmann defined the entropy of a macroscopic system in a macrostate $M$ as the $\\log$ of the volume of phase space (number of microstates) corresponding to $M$. This agrees with the thermodynamic entropy of Clausius when $M$ specifies the locally conserved quantities of a system in local thermal equilibrium (LTE). Here we discuss Boltzmann's entropy, involving an appropriate choice of macro-variables, for systems not in LTE. We generalize the formulas of Boltzmann for dilute gases and of Resibois for hard sphere fluids and show that for macro-variables satisfying any deterministic autonomous evolution equation arising from the microscopic dynamics the corresponding Boltzmann entropy must satisfy an ${\\cal H}$-theorem.", "revisions": [ { "version": "v2", "updated": "2003-06-25T18:50:36.000Z" } ], "analyses": { "keywords": [ "nonequilibrium systems", "hard sphere fluids", "local thermal equilibrium", "appropriate choice", "dilute gases" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 31, "language": "en", "license": "arXiv", "status": "editable", "inspire": 617442 } } }