Inflaton Fragmentation and Oscillon Formation in Three Dimensions

TL;DR

This paper demonstrates through numerical simulations that oscillons, pseudo-stable scalar field configurations, can form abundantly after inflation via inflaton fragmentation, potentially dominating the post-inflationary universe and lasting longer than the Hubble time.

Contribution

It provides the first detailed three-dimensional numerical analysis confirming oscillon formation from inflaton fragmentation and explores their stability and cosmological implications.

Findings

Oscillons can form abundantly in three dimensions after inflation.

Oscillons can dominate the post-inflationary universe.

Oscillons are stable longer than the Hubble time.

Abstract

Analytical arguments suggest that a large class of scalar field potentials permit the existence of oscillons -- pseudo-stable, non-topological solitons -- in three spatial dimensions. In this paper we numerically explore oscillon solutions in three dimensions. We confirm the existence of these field configurations as solutions to the Klein-Gorden equation in an expanding background, and verify the predictions of Amin and Shirokoff for the characteristics of individual oscillons for their model. Further, we demonstrate that significant numbers of oscillons can be generated via fragmentation of the inflaton condensate, consistent with the analysis of Amin. These emergent oscillons can easily dominate the post-inflationary universe. Finally, both analytic and numerical results suggest that oscillons are stable on timescales longer than the post-inflationary Hubble time. Consequently, the post-inflationary universe can contain an effective matter-dominated phase, during which it is dominated by localized concentrations of scalar field matter.