Lattice simulation study of the properties of cold quark matter with a nonzero isospin density

The lattice simulation study of quantum chromodynamics with a nonzero isospin density has been performed. The nonzero isospin density has been introduced by means of the isospin chemical potential $\mu_I$. The simulation has been performed with dynamic $u, d$, and $s$ quarks in the Kogut–Susskind formulation. The static potential of a quark-antiquark pair for various values of the isospin chemical potential has been extracted from the calculated Wilson loops. The dependence of the string tension on the isospin chemical potential has been obtained using data for the interaction potential. The results show that the string tension decreases with an increase in $\mu_I$ and vanishes near $\mu_I\simeq 1200$ MeV. Thus, the confinement/deconfinement phase transition in cold quark matter with the nonzero isospin density has been observed for the first time.