{ "id": "1303.5193", "version": "v1", "published": "2013-03-21T08:57:14.000Z", "updated": "2013-03-21T08:57:14.000Z", "title": "From the Boltzmann $H$-theorem to Perelman's $W$-entropy formula for the Ricci flow", "authors": [ "Xiang-Dong Li" ], "categories": [ "math.DG", "math-ph", "math.MP" ], "abstract": "In 1870s, L. Boltzmann proved the famous $H$-theorem for the Boltzmann equation in the kinetic theory of gas and gave the statistical interpretation of the thermodynamic entropy. In 2002, G. Perelman introduced the notion of $W$-entropy and proved the $W$-entropy formula for the Ricci flow. This plays a crucial role in the proof of the no local collapsing theorem and in the final resolution of the Poincar\\'e conjecture and Thurston's geometrization conjecture. In our previous paper \\cite{Li11a}, the author gave a probabilistic interpretation of the $W$-entropy using the Boltzmann-Shannon-Nash entropy. In this paper, we make some further efforts for a better understanding of the mysterious $W$-entropy by comparing the $H$-theorem for the Boltzmann equation and the Perelman $W$-entropy formula for the Ricci flow. We also suggest a way to construct the \"density of states\" measure for which the Boltzmann $H$-entropy is exactly the $W$-entropy for the Ricci flow.", "revisions": [ { "version": "v1", "updated": "2013-03-21T08:57:14.000Z" } ], "analyses": { "keywords": [ "ricci flow", "entropy formula", "boltzmann equation", "thurstons geometrization conjecture", "poincare conjecture" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1303.5193L" } } }