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Advances in High Energy Physics
Volume 2013 (2013), Article ID 627137, 15 pages
http://dx.doi.org/10.1155/2013/627137
Research Article

Viscous Coefficients of a Hot Pion Gas

Theoretical Physics Division, Variable Energy Cyclotron Centre, 1/AF, Bidhannagar, Kolkata 700064, India

Received 26 March 2013; Accepted 20 May 2013

Academic Editor: Edward Sarkisyan-Grinbaum

Copyright © 2013 Sourav Sarkar. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The steps essentially involved in the evaluation of transport coefficients in linear response theory using Kubo formulas are to relate the defining retarded correlation function to the corresponding time-ordered one and to evaluate the latter in the conventional perturbation expansion. Here we evaluate the viscosities of a pion gas carrying out both the steps in the real-time formulation. We also obtain the viscous coefficients by solving the relativistic transport equation in the Chapman-Enskog approximation to leading order. An in-medium cross-section is used in which spectral modifications are introduced in the propagator of the exchanged .