Axion miniclusters and Bose stars
Axion miniclusters and Bose stars
Evolution of inhomogeneities in the axion field around the QCD epoch is studied numerically, including for the first time important nonlinear effects. It is found that perturbations on scales corresponding to causally disconnected regions at T\ensuremath{\sim}1 GeV can lead to very dense axion clumps, with present density ${\mathrm{\ensuremath{\rho}}}_{\mathit{a}}$\ensuremath{\gtrsim}${10}^{\mathrm{\ensuremath{-}}8}$ g ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}3}$. …