Gapless CFL and its competition with mixed phases

Abstract

We recently argued that as the density of quark matter decreases, there is a continuous transition from the color-flavor-locked (CFL) phase to a gapless "gCFL" phase. The reason is the growing importance of the strange quark mass, and the constraint of electric/color neutrality. In this paper we discuss mixed phases that achieve neutrality by charge seperation, and might offer an alternative to the gCFL phase. We find that none of the obvious mixtures is favored relative to gCFL.