Method of numerical simulation of interacting quantum gas kinetics on finite momentum lattice

We present the efficient and universal numerical method for simulation of interacting quantum gas kinetics on a finite momentum lattice, based on the Boltzmann equation for occupation numbers. Usually, the study of models with two-particle interaction generates the excessive amount of terms in the equations essentially limiting the possible system size. Here we employ the original analytical transformation to decrease the scaling index of the amount of calculations. As a result, lattice sizes as large as 48x48x48 can be simulated, allowing to study realistic problems with complex interaction models. The method was applied to the simulation of weakly interacting Fermi and Bose gases where we calculated the relaxation times depending on the momentum and temperature.

I. O. Kuznetsov, P. F. Kartsev · 2020