Mesoscopic dynamics of fermionic cold atoms — Quantitative analysis of transport coefficients and relaxation times

• Fermi statistical effect hugely increases shear viscosity at low temperature.
• Viscous relaxation times are evaluated based on new formulas derived by RG method.
• It is quantitatively confirmed that RTA is not always reliable even near equilibrium.

We give a quantitative analysis of the dynamical properties of fermionic cold atomic gases in normal phase, such as the shear viscosity, heat conductivity, and viscous relaxation times, using the novel microscopic expressions derived by the renormalization group (RG) method, where the Boltzmann equation is faithfully solved to extract the hydrodynamics without recourse to any ansatz. In particular, we examine the quantum statistical effects, temperature dependence, and scattering-length dependence of the transport coefficients and the viscous relaxation times. The numerical calculation shows that the relation τπ=η/Pτπ=η/P, which is derived in the relaxation-time approximation (RTA) and is used in most of the literature, turns out to be satisfied quite well, while the similar relation for the viscous relaxation time τJτJ of the heat conductivity is satisfied only approximately with a considerable error.