Broken phase solitons in the baby Skyrme model

The baby Skyrme model is studied in the presence of an isospin chemical potential. The inclusion of the chemical potential leads to an asymmetric vacuum. As a result, the residual SO(2) symmetry of the model is broken into the discrete Z2 group. Nontrivial topological field configurations are found to be allowed in the model. We obtained numerical solutions for the solitons on top of the new vacuum by minimizing the energy functional using a simulated annealing algorithm. All the calculations were performed by relaxing the rotational symmetry inherent to the hedgehog approximation. The corresponding soliton solutions exhibit discrete symmetries imposed by the new vacuum.