Gravitational reheating at strong coupling

Abstract

We use gauge/gravity correspondence to study the gravitational reheating of strongly coupled gauge theories in the rapid exit from the long inflationary (de Sitter) phase. We estimate the maximal reheating temperature of holographic models in $d$-spatial dimensions, which scale invariance is explicitly broken by a source term for an operator ${\cal O}_\Delta$ of dimension $\frac d2+\frac 12< \Delta< d+1$, as well as the top-down ${\cal N}=2^*$ and the cascading gauge theories. The reheating is most efficient when the inflationary phase Hubble constant is much larger than the mass scale of the conformal symmetry breaking of the theory, and for theories with the conformal symmetry breaking operators that are close to marginal.