Properties of gluons in color superconductors

I give an introduction to color superconductivity in cold, dense quark matter. I focus in particular on how the solution to the gap equation is qualitatively different in ordinary BCS theory with local four-fermion interactions, in theories with non-local, but screened boson exchange, and in QCD, where magnetic gluon exchange is not screened at zero temperature. I argue that a reliable computation of the gap parameter requires knowledge of the gluon self-energy in a color superconductor. As a first step to determine the gluon self-energy, I report calculations of the Debye and Meissner masses in two- and three-flavor color superconductors.