Pion superfluid phase transition at finite isospin chemical potential.

The pion superfluidity phase transition at T - μ I and μ q - μ I planes are studied in the framework of Dyson-Schwinger equations. The rainbow truncation and Gaussian effective gluon propagator are employed to calculate pion condensate, ⟨ π ⟩ , as a function of μ I at finite T and μ q . At T = (0 , 80 , 113 , 120) MeV, the ⟨ π ⟩ keeps zero when μ I is less than a critical value μ Ic (T) . The ⟨ π ⟩ at T = 113 MeV agrees with the lattice QCD result. At the T - μ I plane, the pion superfluid phase appears at low temperature and high isospin chemical potential region. At finite μ q , ⟨ π ⟩ varying with μ I almost coincide for μ q < 400 MeV. At μ q - μ I plane, the pion superfluid phase appears at μ I ≳ m π when μ q < 400 MeV. [ABSTRACT FROM AUTHOR]