  We consider a phase transition induced by the growth of Q-balls in a false
vacuum. Such a transition could occur in the early universe in the case of
broken supersymmetry with a metastable false vacuum. Small Q-balls with a
negative potential energy can grow in a false vacuum by accretion of global
charge until they reach critical size, expand, and cause a phase transition. We
consider the growth of Q-balls from small to large, using the Bethe-Salpeter
equation to describe small charge solitons and connecting to the growth of
larger solitons for which the semiclassical approximation is reliable. We thus
test the scenario in a simplified example inspired by supersymmetric extensions
of the standard model.
