Nonperturbative preheating decay of postinflationary condensates often results in a high density, low momenta, nonthermal gas. In the case where the nonperturbative classical evolution also leads to $Q$ balls, this effect shields them from instant dissociation, and may radically change the thermal history of the Universe. For example, in a large class of inflationary scenarios, motivated by the minimal supersymmetric standard model and its embedding in string theory, the reheat temperature changes by a multiplicative factor of ${10}^{12}$.

• Received 23 October 2005

DOI:https://doi.org/10.1103/PhysRevLett.96.031303