Analytic Solution of the Boltzmann Equation in an Expanding System
Phys. Rev. Lett. 116, 022301 – Published 15 January, 2016
DOI: https://doi.org/10.1103/PhysRevLett.116.022301
Abstract
For a massless gas with a constant cross section in a homogeneous, isotropically expanding spacetime we reformulate the relativistic Boltzmann equation as a set of nonlinear coupled moment equations. For a particular initial condition this set can be solved exactly, yielding the first analytical solution of the Boltzmann equation for an expanding system. The nonequilibrium behavior of this relativistic gas can be mapped onto that of a homogeneous, static nonrelativistic gas of Maxwell molecules.