Shear viscosities from Kubo formalism in a large-Nc Nambu-Jona-Lasinio model

Regular Article - Theoretical Physics


In this work the shear viscosity of strongly interacting matter is calculated within a two-flavor Nambu-Jona-Lasinio model as a function of temperature and chemical potential. The general Kubo formula is applied, incorporating the full Dirac structure of the thermal quark spectral function and avoiding commonly used on-shell approximations. Mesonic fluctuations contributing via Fock diagrams provide the dominant dissipative processes. The resulting ratio η/s (shear viscosity over entropy density) decreases with temperature and chemical potential. Interpolating between our NJL results at low temperatures and hard thermal loop results at high temperatures a minimum slightly above the AdS/CFT benchmark η/s = 1/4τ is obtained.

Copyright information

© SIF, Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  1. 1.Physik DepartmentTechnische Universität MünchenGarchingGermany
  2. 2.ECTVilla TambosiVillazzano (TN)Italy

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