Nonlinear axions and how to observe them

17.05.2022 13:30 – 14:30

Axions are some of the best-motivated dark matter candidates, with vacuum misalignment providing a very natural and well-understood cosmological production mechanism. Misalignment also, however, allows an axion to naturally explore the nonlinear parts of its potential at early times. If the initial misalignment angle is large or if there are multiple interacting axions in the theory, this can result in a parametric resonance that significantly enhances density fluctuations and leads to the eventual formation of bound structures. Over a broad range of axion mass, from $10^{-22}$ eV up to eV scales, such a resonance can have observable consequences ranging from gravitational lensing signatures to changes to early star formation to modifications of direct detection sensitivities. In this talk I will discuss the generic features of these early dynamics with an emphasis on the present-day and near-future observational techniques that can probe them.

Lieu

Bâtiment: Ecole de Physique

Room 234

entrée libre