Study on Cooling of Positronium for Bose-Einstein Condensation

A proposed new method of cooling positronium is to realize the Bose-Einstein condensation (BEC) of positronium. We perform detailed studies of three processes: (1) thermalization processes between positronium and the silica walls of a cavity, (2) Ps-Ps scattering and (3) laser cooling. The thermalization process is shown to be not sufficient for BEC. Ps-Ps collision is shown to have a big effect on the cooling performance. We combine both methods and establish an efficient cooling process for BEC. We also propose a new optical laser system for the cooling.