Boson stars and oscillatons in an inflationary universe

TL;DR

This paper investigates the behavior of boson stars and oscillatons in an inflationary universe, revealing that they lose mass via scalar radiation at an exponentially slow rate when the universe's expansion is slow.

Contribution

It provides a theoretical analysis of scalar lumps in de Sitter space, showing their mass loss dynamics due to inflationary expansion.

Findings

Boson stars and oscillatons emit scalar radiation in inflationary backgrounds.

Mass loss rate is exponentially suppressed with slow expansion.

Scalar lumps remain relatively stable in slowly expanding universes.

Abstract

Spherically symmetric gravitationally bound, oscillating scalar lumps (boson stars and oscillatons) are considered in Einstein's gravity coupled to massive scalar fields in 1+D dimensional de Sitter-type inflationary space-times. We show that due to inflation bosons stars and oscillatons lose mass through scalar radiation, but at a rate that is exponentially small when the expansion rate is slow.