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

We simulate 2-flavor lattice QCD at finite isospin chemical potential μI, for temperatures close to the finite temperature transition from hadronic matter to a quark-gluon plasma. The μI dependence of the transition coupling is observed and used to estimate the decrease in the transition temperature with increasing μI. These simulations are performed on an 83x4 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 μ, suggest that the position of the small μ and small μI transitions should be the same for μI=2μ, and we argue that the nature of these transitions should be the same. For all μImπ/2 over the considered range of quark masses. For μI>mπ and a small isospin (I3) breaking term λ, we do find evidence of a critical endpoint which would indicate that, for λ=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