Kolmogorov-type non-thermal fixed points and beyond of far-from-equilibrium dilute system: ultra-cold Fermi gas

Abstract: The far-from-equilibrium dynamics driven by the scattering from next-to-leading-order (NLO) corrections in the quantum field theory has stationary solutions for the particle distribution characterized as the Kolmogorov-type non-thermal fixed points. The dynamics of the spatially homogeneous, isotropic dilute ultra-cold Fermi gas is investigated, and its kinetic equation confirms the Kolmogorov-type non-thermal fixed points in the perturbation theory by the quasi-particle assumption, in contrast to the wave turbulence of the weakly coupled ultra-cold Bose gas. In addition, other stationary states are found without the quasi-particle assumption and in a strongly coupled system. These analytical solutions provide chances for future experiments and numerical simulations in search of far-from-equilibrium stationary states of the dilute system.