Soliton Systems at Finite Temperatures and Finite Densities

The finite-density and finite-temperature phase portraits of the baby-Skyrme and Skyrme models are investigated. Both grand-canonical and canonical approaches are employed. The grand-canonical approach can be used to find the ``natural’’ crystal structure of the baby-Skyrme model and it is shown to have triangular symmetry. The phase portraits include solid, liquid and phase-coexistence between solids and vacuum states. Furthermore, a chiral phase transition can be observed for both models. The phase portrait of the Skyrme model is compared with that expected of strongly interacting matter, and we also contrast our results to other models.