Dense skyrmion systems

The Skyrme model is used to investigate dense baryonic matter. Solutions of static close-packed skyrmions in arrays with fcc symmetry as well as bcc and intermediate symmetry are considered as a function of the density, and the phase transition into regular arrays of half-skyrmions is investigated. The fcc array of skyrmions has lowest energy in the condensed half-skyrmion phase but not in the uncondensed phase, in which the energy depends very little on the precise symmetry. The lowest energy, just 3.8% above the theoretical lower bound, occurs in the condensed half-skyrmion phase corresponding to the fcc array.