Axiverse Baryogenesis

Abstract

The QCD axion may offer a unified origin for the baryon asymmetry and dark matter through axiogenesis. However, in the minimal QCD axion scenario, axiogenesis either underproduces baryons or overproduces dark matter, and the required kinetic misalignment initial conditions are in tension with axion quality. In this \textit{Letter}, we demonstrate that the axiverse naturally resolves these tensions: the QCD axion emerges as a linear combination of multiple axion-like fields, evading the overclosure problem thanks to new dissipation channels , while introducing additional Peccei--Quinn symmetries that ensure a high quality QCD axion. We illustrate these points in a toy model with two axions. This framework predicts a rich phenomenology within experimental reach, including dark matter detection prospects, astrophysical signals, and collider signatures.