Hartree-Bogoliubov theory of quark matter. Condensation energy in strange quark matter

We apply the Hartree-Bogoliubov theory to quark matter and discuss the stability of strange quark matter in the MIT bag model. Taking the one-gluon exchange potential between two quarks, we find attractive force between two-quarks in the color-triplet and spin-parallel state. If the Hartree-Bogoliubov approximation is applied to the quark matter, the ground state becomes a superconducting (BCS) state. It is shown that the condensation energy becomes larger with the quark density and is favorable for the stability of the strange quark matter. (author)