Energy distribution and equation of state of the early Universe: matching the end of inflation and the onset of radiation domination

Stefan Antusch; Daniel G. Figueroa; Kenneth Marschall; Francisco Torrenti

doi:10.1016/j.physletb.2020.135888

paper

Energy distribution and equation of state of the early Universe: matching the end of inflation and the onset of radiation domination

arXiv:2005.07563 · doi:10.1016/j.physletb.2020.135888

Abstract

We study the energy distribution and equation of state of the universe between the end of inflation and the onset of radiation domination (RD), considering observationally consistent single-field inflationary scenarios, with a potential 'flattening' at large field values, and a monomial shape $V (ϕ) \propto ∣ ϕ ∣^{p}$ around the origin. As a proxy for (p)reheating, we include a quadratic interaction $g^{2} ϕ^{2} X^{2}$ between the inflaton $ϕ$ and a light scalar 'daughter' field $X$ , with $g^{2} > 0$ . We capture the non-perturbative and non-linear nature of the system dynamics with lattice simulations, obtaining that: $i)$ the final energy transferred to $X$ depends only on $p$ , not on $g^{2}$ , ; $ii)$ the final transfer of energy is always negligible for $2 \leq p < 4$ , and of order $\sim 50%$ for $p \geq 4$ ; $iii)$ the system goes at late times to matter-domination for $p = 2$ , and always to RD for $p > 2$ . In the latter case we calculate the number of e-folds until RD, significantly reducing the uncertainty in the inflationary observables $n_{s}$ and $r$ .

7 pages + references, 5 figures. It matches published version

Energy distribution and equation of state of the early Universe: matching the end of inflation and the onset of radiation domination

Abstract

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