Do dark matter axions form a condensate with long-range correlation?

Abstract

The authors investigate the formation of Bose-Einstein condensates from axion dark matter, and it is shown that a homogeneous condensate with long range correlations is unstable when $a\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}c\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}v\phantom{\rule{0}{0ex}}e$ interactions like gravity are taken into account. Instead many Bose-Einstein condensates in form of Bose stars with correlation lengths much below galactic scales are created.