A Model of Anthropic Reasoning, Addressing the Dark to Ordinary Matter Coincidence

TL;DR

This paper explores a multiverse-based model where inflation after Peccei-Quinn symmetry breaking allows large axion scales, potentially explaining the dark matter and baryon matter density coincidence.

Contribution

It proposes a novel multiverse scenario linking inflation timing and axion scale, offering an explanation for dark and baryon matter density coincidence.

Findings

Large axion scales are possible with post-Peccei-Quinn inflation.

Regions with small initial misalignment dominate observer count.

The model provides a potential explanation for dark and baryon matter density equality.

Abstract

If inflation occurs after the breaking of Peccei-Quinn symmetry then large values of the breaking scale $F$, which are forbidden in conventional axion cosmology, are permitted, provided that we inhabit a region of the Multiverse where the initial misalignment is small. Regions having approximately this initial misalignment may occupy a small volume of the Multiverse, but they contain a large fraction of potential observers. This scenario has many consequences, including a possible explanation of the approximate equality of dark and baryon matter densities.