EPJ Web of Conferences 13, 06004 (2011)
https://doi.org/10.1051/epjconf/20111306004

Transport coefficients in non-quasiparticle systems

Institute of Physics, BME Technical University, H-l 111 Budapest, Hungary

^a e-mail: jakovac@phy.bme.hu

Abstract

Transport coefficients, in particular the shear viscosity to entropy density ratio are studied in systems where the small-width quasiparticle assumption is not valid. It is found that η/s has no universal lower bound, the minimal value depends on the system and the temperature, and can be even zero. We construct models where the 1/4π conjectured bound is violated.