Axiogenesis and Ultralight Dark Matter

We proposed a mechanism called axiogenesis to explain the observed cosmological excess of matter over antimatter. A rotation of the QCD axion is induced by explicit Peccei-Quinn symmetry breaking in the early universe. The rotation corresponds to the asymmetry of the PQ charge, which is converted into the baryon asymmetry via QCD and electroweak sphaleron transitions. The concrete model we explore predicts a small decay constant and has close connections with axion dark matter and new physics at the colliders. In regard to ultralight dark matter, we propose new non-thermal production mechanisms for QCD axions and dark photons. These complimentary ideas arise from different axion initial conditions and expand the parameter space to the regions of interest for the extensive experimental searches. Other potential
signatures include dark matter ultracompact minihalos, warm dark matter, and gravitational waves.