  We studied a single atom trapped in an optical tweezer interacting with a
thermal bath of ultracold atoms of a different species. Because of the
collisions between the trapped atom and the bath atoms, the trapped atom
undergoes changes in its vibrational states occupation to reach thermal
equilibrium with the bath. By using Monte Carlo simulations, we characterized
the single atom's thermalization process, and we studied how this can be used
for cooling. Our simulations demonstrate that, within known experimental
limitations, it is feasible to cool a trapped single atom with a thermal bath.
