Finite temperature transition for 2-flavor lattice QCD at finite isospin density

We simulate 2-flavor lattice QCD at finite isospin chemical potential ₈, for temperatures close to the finite temperature transition from hadronic matter to a quark-gluon plasma. The ₈ dependence of the transition coupling is observed and used to estimate the decrease in the transition temperature with increasing ₈. These simulations are performed on an 8^34 lattice at three different quark masses. Our estimate of the magnitude of the fluctuations of the phase of the fermion determinant at small quark-number chemical potential, suggest that the position of the small and small ₈ transitions should be the same for ₈=2, and we argue that the nature of these transitions should be the same. For all ₈m_/2 over the considered range of quark masses. For ₈>m_ and a small isospin (I₃) breaking term, we do find evidence of a critical endpoint which would indicate that, for =0, there is a tricritical point on the phase boundary where the pion condensate evaporates, where this phase transition changes from second to first-order.