Axion Bose-Einstein Condensation: a modelbeyond Cold Dark Matter

摘要

Cold dark matter axions form a Bose-Einstein condensate if the axions thermalize. Recently, it was found [1] that they do thermalize when the photon temperature reaches T ～ 100 eV(fl10~(12)GeV)~(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.