1:30 pm VIA ZOOM
The Gravitino Swampland Conjecture, Evan McDonough, UChicago
The QCD axion solves the strong CP problem and is an attractive dark matter candidate. In the case when the relic density is produced by symmetry breaking in the early Universe, the model is uniquely predictive, with a single free parameter specifying the relic density and particle mass. I will review this scenario and recent predictions of the particle mass, that lie somewhere around 1 meV. The model also makes predictions about the existence of low mass (<1e-10 Msol) and dense objects known as miniclusters, which can have interesting effects on astrophysics and direct detection. Finally, I will discuss recent ideas to detect meV axions using antiferromagnetic materials.