{ "id": "1408.7043", "version": "v1", "published": "2014-08-29T14:54:30.000Z", "updated": "2014-08-29T14:54:30.000Z", "title": "Electric Conductivity from the solution of the Relativistic Boltzmann Equation", "authors": [ "A. Puglisi", "S. Plumari", "V. Greco" ], "comment": "9 pages, 9 figures", "categories": [ "hep-ph", "nucl-th" ], "abstract": "We present numerical results of electric conductivity $\\sigma_{el}$ of a fluid obtained solving the Relativistic Transport Boltzmann equation in a box with periodic boundary conditions. We compute $\\sigma_{el}$ using two methods: the definition itself, i.e. applying an external electric field, and the evaluation of the Green-Kubo relation based on the time evolution of the current-current correlator. We find a very good agreement between the two methods. We also compare numerical results with analytic formulas in Relaxation Time Approximation (RTA) where the relaxation time for $\\sigma_{el}$ is determined by the transport cross section $\\sigma_{tr}$, i.e. the differential cross section weighted with the collisional momentum transfer. We investigate the electric conductivity dependence on the microscopic details of the 2-body scatterings: isotropic and anisotropic cross-section, and massless and massive particles. We find that the RTA underestimates considerably $\\sigma_{el}$; for example at screening masses $m_D \\sim \\,T$ such underestimation can be as large as a factor of 2. Furthermore, we study a more realistic case for a quark-gluon system (QGP) considering both a quasi-particle model, tuned to lQCD thermodynamics, as well as the case of a pQCD gas with running coupling. Also for these cases more directly related to the description of the QGP system, we find that RTA significantly underestimate the $\\sigma_{el}$ by about a $60-80\\%$.", "revisions": [ { "version": "v1", "updated": "2014-08-29T14:54:30.000Z" } ], "analyses": { "subjects": [ "12.38.Mh", "25.75.Nq", "47.75.+f", "52.25.Fi" ], "keywords": [ "relativistic boltzmann equation", "relativistic transport boltzmann equation", "collisional momentum transfer", "transport cross section", "differential cross section" ], "tags": [ "journal article" ], "publication": { "doi": "10.1103/PhysRevD.90.114009", "journal": "Physical Review D", "year": 2014, "month": "Dec", "volume": 90, "number": 11, "pages": 114009 }, "note": { "typesetting": "TeX", "pages": 9, "language": "en", "license": "arXiv", "status": "editable", "inspire": 1312992, "adsabs": "2014PhRvD..90k4009P" } } }