Thermodynamics of strong coupling 2-color QCD with chiral and diquark condensates

Two-color quantum chromodynamics (QCD with Nc=2) at finite temperature T and chemical potential μ is revisited in the strong coupling limit on the lattice with staggered fermions. The phase structure in the space of T, μ, and the quark mass m is elucidated with the use of the mean field approximation and the 1/d expansion (d being the number of spatial dimensions). We put special emphasis on the interplay among the chiral condensate 〈q̄q〉, the diquark condensate 〈qq〉, and the quark density 〈q†q〉 in the T-μ-m space. Simple analytic formulae are also derived without assuming μ nor m being small. Qualitative comparisons are made between our results and those of recent Monte-Carlo simulations in 2-color QCD.