Skyrme model and Isospin Chemical Potential

Abstract

We discuss the stability of the Skyrmion solution in the presence of a finite isospin chemical potential $\mu$. Solving numerically the mass of the Skyrmion as function of $\mu$, we find a critical value ${\mu }_c=222.8$ MeV where the Skyrmion mass vanishes. We compare the exact numerical treatment with an analytical discussion based on a special shape for the profile of the Skyrmion due to Atiyah and Manton. The extension of this ansatz for finite $\mu$ works quite well for $\mu <121$ MeV. Then, for small values of $\mu$, where the analytical approach is valid, we consider the possibility of having an angular deformation for the Skyrmionic profile, which is possible for finite values of $\mu$. This is however, a small effect. Finally we introduce finite temperature corrections, which strength the instability induced by the chemical potential, finding the dependence of the critical temperature on $\mu$.

Comments: 13 pages, 7 figures