Dark Matter in Models of String Cosmology

TL;DR

This paper explores how dark matter could originate from quantum fluctuations during string cosmology inflation, focusing on scalar particles like the QCD axion and their resulting spectra.

Contribution

It introduces models of dark matter production in string cosmology, analyzing both small fluctuation spectra and large fluctuation effects of axion-like fields.

Findings

Small fluctuation spectra lead to nonthermal dark matter distributions.

Large fluctuations of the QCD axion can significantly impact dark matter abundance.

Abstract

The origin of dark matter in the universe may be weakly interacting scalar particles produced by amplification of quantum fluctuations during a period of dilaton-driven inflation. We present two interesting cases, the case of small fluctuations, and the resulting nonthermal spectrum, and the case of large fluctuations of a field with a periodic potential, the QCD axion.