Axion Bose-Einstein Condensation: a model beyond Cold Dark Matter

Abstract

Cold dark matter axions form a Bose-Einstein condensate if the axions thermalize. Recently, it was found that they do thermalize when the photon temperature reaches T ~ 100 eV(f/10^12GeV)^1/2 and that they continue to do so thereafter. We discuss the differences between axion BEC and CDM in the linear regime and the non-linear regime of evolution of density perturbations. We find that axion BEC provides a mechanism for the production of net overall rotation in dark matter halos, and for the alignment of cosmic microwave anisotropy multi-poles.

Comments: 5 pages. Presented as "Axion BEC" in Axions 2010 conference at UF(http://www.phys.ufl.edu/research/Axions2010/).