Overdensities in the post-inflationary universe can grow via gravitational collapse. In simple models this happens long after inflation because the perturbations are initially small. However, parametric resonance after inflation can dramatically boost the amplitude of the perturbations and we explore how this can accelerate the subsequent gravitational collapse.
We perform first-of-their-kind high-resolution simulations that span the resonant phase and the subsequent gravitational collapse of the inflaton field. The calculations segue from a full Klein-Gordon treatment of resonance to a computationally efficient Schrödinger-Poisson description that accurately captures the gravitational dynamics when most quanta are nonrelativistic.
Abstract
The postinflationary Universe can pass through a long epoch of effective matter-dominated expansion. This era may allow for both the parametric amplification of initial fluctuations and the gravitational collapse of inflaton perturbations. We perform first-of-their-kind high-resolution simulations that span the resonant phase and subsequent gravitational collapse of the inflaton field by segueing from a full Klein-Gordon treatment of resonance to a computationally efficient Schrödinger-Poisson description that accurately captures the gravitational dynamics when most quanta are nonrelativistic. We consider a representative example in which resonance generates 𝒪(10-1) overdensities and gravitational collapse follows promptly as resonance ends. We observe the formation of solitonic cores inside inflaton halos and complex gravitational dynamics on scales of 10-27 m, greatly extending the possible scope of nonlinear postinflationary gravitational dynamics.
- Eggemeier, Hayman, Niemeyer and Easther
- Postinflationary structure formation boosted by parametric self-resonance
- Phys. Rev. D 109, 043521 or ArXiV:2311.08780
Schrodinger-Poisson halo in the early universe.