If dark matter in the galactic halo is composed of bosons that form a Bose-Einstein condensate then it is likely that the rotation of the halo will lead to the nucleation of vortices. After a review of the Gross-Pitaevskii equation, the Thomas-Fermi approximation and vortices in general, we consider vortices in detail. We find strong bounds for the boson mass, interaction strength, the shape and quantity of vortices in the halo, the critical rotational velocity for the nucleation of vortices and, in the Thomas-Fermi regime, an exact solution for the mass density of a single, axisymmetric vortex.PACS numbers: 05.30.Jp, 95.35.+d

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We consider a polaronic model in which impurity fermions interact with background bosons in a dipolar condensate. The polaron in this model emerges as an impurity dressed with a cloud of phonons of the dipolar condensate, which, due to the competition between the attractive and repulsive parts of the dipole-dipole interaction, obey an anisotropic dispersion spectrum. We study how this anisotropy affects theČerenkov-like emission of Bogoliubov phonon modes, which can be directly verified by experiments in which a dipolar Bose-Einstein condensate moves against an obstacle. We also study the spectral function of impurity fermions, which is directly accessible to the momentum-resolved rf spectroscopy in cold atoms.

Yin and Radzihovsky [1] recently developed a self-consistent extension of a Bogoliubov theory, in which the condensate number density nc is treated as a mean field that changes with time, in order to analyze a JILA experiment by Makotyn et al.[2] on a 85 Rb Bose gas following a deep quench to a large scattering length. We apply this theory to construct a closed set of equations that highlight the role ofṅc, which is to induce an effective interaction between quasiparticles. We show analytically that such a system supports a steady state characterized by a constant condensate density and a steady but periodically changing momentum distribution, whose time average is described exactly by the generalized Gibbs ensemble. We discuss how theṅc-induced effective interaction, which cannot be ignored on the grounds of the adiabatic approximation for modes near the gapless Goldstone mode, can significantly affect condensate populations and Tan's contact for a Bose gas that has undergone a deep quench.