Was the Universe Actually Radiation Dominated Prior to Nucleosynthesis?

Understand

Maybe not.

• String theory approaches to both beyond the Standard Model and Inflationary model building generically predict the existence of scalars (moduli) that are light compared to the scale of quantum gravity.
• These moduli become displaced from their low energy minima in the early universe and lead to a prolonged matter-dominated epoch prior to BBN.
• In this paper, we examine whether non-perturbative effects such as parametric resonance or tachyonic instabilities can shorten, or even eliminate, the moduli condensate and matter-dominated epoch.