Superconductivity in quark matter

We explore the possibility of superconductivity of a system composed of an infinite number of quarks with a single flavor. If we assume that such quarks interact which each other via the one-gluon exchange potential, we find an attractive force between a pair of quarks in the color-triplet and spin-parallel state. Applying the mean field (BCS) theory to the system, we have a new superconducting state that has lower energy than the normal (degenerate Fermi gas) state. It is also shown that our system is described by both usual quasi-particles with a finite energy gap and gapless quasi-particles.