Quark and gluon condensates at a finite isospin chemical potential

The nonperturbative vacuum of quantum chromodynamics at a finite isospin chemical potential has been studied. Low-energy relations for the quark and gluon condensates have been derived ab initio. Analytical expressions for the quark and gluon condensates in the pion-condensate phase have been obtained at the tree level of the chiral perturbation theory. It has been shown that the quark condensate decreases with increasing $\mu_I$, whereas the gluon condensate increases.