Characterizing the post-inflationary reheating history, Part II: Multiple interacting daughter fields

Stefan Antusch; Kenneth Marschall; Francisco Torrenti

doi:10.1088/1475-7516/2023/02/019

paper

Characterizing the post-inflationary reheating history, Part II: Multiple interacting daughter fields

arXiv:2206.06319 · doi:10.1088/1475-7516/2023/02/019

Abstract

We characterize the post-inflationary dynamics of an inflaton $ϕ$ coupled to multiple interacting daughter fields $X_{n}$ ( $n = 1, \dots N_{d}$ ) through quadratic-quadratic interactions $g_{n}^{2} ϕ^{2} X_{n}^{2}$ . We assume a monomial inflaton potential $V (ϕ) \propto ∣ ϕ ∣^{p}$ ( $p \geq 2$ ) around the minimum. By simulating the system in 2+1-dimensional lattices, we study the post-inflationary evolution of the energy distribution and equation of state, from the end of inflation until a stationary regime is achieved. We show that in this scenario, the energy transferred to the daughter field sector can be larger than $50%$ , surpassing this way the upper bound found previously for single daughter field models. In particular, for $p \geq 4$ the energy at very late times is equally distributed between all fields, and only $100/ (N_{d} + 1) %$ of the energy remains in the inflaton. We also consider scenarios in which the daughter fields have scale-free interactions $λ_{nm} X_{n}^{2} X_{m}^{2}$ , including the case of quartic daughter field self-interactions (for $n = m$ ). We show that these interactions trigger a resonance process during the non-linear regime, which in the single daughter field case already allows to deplete more than $50%$ of the energy from the inflaton for $p \geq 4$ .

23 pages + appendix, 15 figures

Characterizing the post-inflationary reheating history, Part II: Multiple interacting daughter fields

Abstract

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