Abstracts

Matthew Kleban

Universal axions: cosmology in an axion landscape

I will describe a novel technique that renders theories of N axion fields analytically and numerically tractable. The number of local minima of the potential scales exponentially with N, making a brute-force analysis impossible for N >> 1. With the help of this new technique, I will show that for N~100 and with Planckian or GUT/string energy scales one finds values of the vacuum energy consistent with the observed dark energy. Moreover, this landscape supports a variety of types of slow-roll inflation that can take place after tunneling from a local minimum, and it naturally contains one or more ultralight fields that can serve as fuzzy dark matter. Hence one model with no small parameters and ~100 fields with random couplings can simultaneously account for the big bang (tunneling), inflation, dark matter, and dark energy.