The European Physical Journal A

, Volume 31, Issue 4, pp 848–850 | Cite as

Transport coefficients in Chiral Perturbation Theory

  • D. Fernández-Fraile
  • A. Gómez Nicola
QNP 2006


We present recent results on the calculation of transport coefficients for a pion gas at zero chemical potential in Chiral Perturbation Theory (ChPT) using the Linear Response Theory (LRT). More precisely, we show the behavior of DC conductivity and shear viscosity at low temperatures. To compute transport coefficients, the standard power counting of ChPT has to be modified. The effects derived from imposing unitarity are also analyzed. As physical applications in relativistic heavy-ion collisions, we show the relation of the DC conductivity to soft-photon production and phenomenological effects related to a non-zero shear viscosity. In addition, our values for the shear viscosity to entropy ratio satisfy the KSS bound.


11.10.Wx Finite-temperature field theory 12.39.Fe Chiral Lagrangians 25.75.-q Relativistic heavy-ion collisions 


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Copyright information

© Società Italiana di Fisica and Springer-Verlag 2007

Authors and Affiliations

  • D. Fernández-Fraile
    • 1
  • A. Gómez Nicola
    • 1
  1. 1.Departamentos de Fısica Teórica I y IIUniversidad ComplutenseMadridSpain

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