Speaker
Description
Dark matter may be composed of sufficiently light bosonic fields, such as axions or dark photons, whose wave nature can affect structure formation on astrophysical and cosmological scales. In this talk, I will describe recent progress in connecting the early-universe production of such fields to their later gravitational evolution and observational signatures. Post-inflationary production mechanisms can naturally generate dark matter with both velocity dispersion, leading to free-streaming suppression, and white-noise/isocurvature fluctuations. I will discuss a general framework for following the growth of correlators and density perturbations in particle and wave dark matter, including multi-species cases and fields with different spin. I will also describe recent 3+1 dimensional simulations of ultra-light axions with significant warmth and isocurvature enhancements, which show early nonlinear structure formation, including solitons, by (z\sim 100). These results provide a path toward connecting dark matter mass, spin, production mechanism, and species multiplicity to observables such as Milky Way satellites, Ly(\alpha), 21-cm measurements, and high-redshift structure.
| Primary Abstract Topic | Theory: Axions and Wave-Like-DM |
|---|