Dark Matter Superfluidity and Galactic Dynamics
  We propose a unified framework that reconciles the stunning success of MOND
on galactic scales with the triumph of the LambdaCDM model on cosmological
scales. This is achieved through the physics of superfluidity. Dark matter
consists of self-interacting axion-like particles that thermalize and condense
to form a superfluid in galaxies, with ~mK critical temperature. The superfluid
phonons mediate a MOND acceleration on baryonic matter. Our framework naturally
distinguishes between galaxies (where MOND is successful) and galaxy clusters
(where MOND is not): dark matter has a higher temperature in clusters, and
hence is in a mixture of superfluid and normal phase. The rich and well-studied
physics of superfluidity leads to a number of striking observational
signatures.
