Pion Superfluidity in Baryonic Matter

We investigated two pion condensed phases in the frame of two flavor Nambu‐Jona‐Lasinio model at finite baryon density: the homogeneous and isotropic Sarma phase and inhomogeneous and anisotropic LOFF phase. At small isospin chemical potential μ_I, the Sarma state is free from the Sarma instability and magnetic instability due to the strong coupling and large enough effective quark mass. At large μ_I, while the Sarma instability can be cured via fixing baryon density n_B to be nonzero, its magnetic instability implies that the LOFF state is favored than the Sarma state. In the intermediate μ_I region, the stable ground state is the Sarma state at higher n_B and LOFF state at lower n_B.