Growth of Linear Perturbations in a Universe with Superfluid Dark Matter
  The Lambda-Cold Dark Matter (LCDM) model agrees with most of the cosmological
observations, but has some hindrances from observed data at smaller scales such
as galaxies. Recently, Berezhiani and Khoury (2015) proposed a new theory
involving interacting superfluid dark matter with three model parameters, which
explains galactic dynamics with great accuracy. In the present work, we study
the cosmological behaviour of this model in the linear regime of cosmological
perturbations. In particular, we compute both analytically and numerically the
matter linear growth factor and obtain new bounds for the model parameters
which are significantly stronger than previously found. These new constraints
come from the fact that structures within the superfluid dark matter framework
grow quicker than in LCDM, and quite rapidly when the DM-baryon interactions
are strong.
