Simulations of multicomponent relativistic thermalization
  Multicomponent relativistic fluids have been studied for decades. However,
simulating the dynamics of the particles and fluids in such a mixture has been
a challenge due to the fact that such simulations are computationally expensive
in three spatial dimensions. Here, we report on the development and application
of a multi dimensional relativistic Monte Carlo code to explore of the
thermalization process in a relativistic multicomponent environment in a
computationally inexpensive way. As an illustration we simulate the fully
relativistic three dimensional Brownian-motion-like solution to the
thermalization of a high mass particle (proton) in a bath of relativistic
low-mass particles (electrons). We follow the thermalization and ultimate
equilibrium distribution of the Brownian-like particle as can happen in the
cosmic plasma during big bang nucleosynthesis. We also simulate the
thermalization of energetic particles injected into the plasma as can occur,
for example, by the decay of massive unstable particles during the big bang.
