Pure quantum extension of the semiclassical Boltzmann-Uehling-Uhlenbeck equation (2109.07021v2)

Abstract: The Boltzmann equation is the traditional framework in which one extends the time-dependent mean field classical description of a many-body system to include the effect of particle-particle collisions in an approximate manner. A semiclassical extension of this approach to quantum many body systems was suggested by Uehling and Uhlenbeck in 1933 for both Fermi and Bose statistics, and many further developments of this approach are known as the BoltzmannUehling-Uhlenbeck (BUU) equations. Here I introduce a pure quantum version of the BUU type of equations, which is mathematically equivalent to a generalized Time-Dependent Density Functional Theory extended to superfluid systems. As expected, during non-equilibrium processes the quantum Boltzmann one body entropy increases during evolution.