Fate of chiral critical point under the strong isospin asymmetry

Abstract: We study the influence of the isospin asymmetry on the phase structure of strongly interacting quark matter near the critical point (CP) using a Ginzburg-Landau approach. The effect is found to be drastic, not only bringing about the shift of the location of the CP, but resulting in a rich phase structure in the vicinity of the CP. In particular, new tricritical and triple points emerge as soon as the isospin density becomes finite. Moreover, we find the CP being washed out from the phase diagram due to the stabilization of a homogeneous charged pion condensate when the isospin chemical potential exceeds a critical value. We derive a model-independent universal relation between the critical isospin chemical potential and the chiral condensate at the CP. We also study the effect of the $\mathrm{U}(1)_\mathrm{A}$ anomaly on the phase transition to the pion condensate in the vicinity of chiral crossover.