Q-ball formation through the Affleck-Dine mechanism -: art. no. 041301

We present the full nonlinear calculation of the formation of a Q ball through the Affleck-Dine (AD) mechanism by numerical simulations. It is shown that large Q balls are actually produced by the fragmentation of the condensate of a scalar field whose potential is very flat. We find that the typical size of a Q ball is determined by the most developed mode of linearized fluctuations, and almost all the initial charges which the AD condensate carries are absorbed into the formed Q balls, whose sizes and the charges depend only on the initial charge densities.