Bose–Einstein condensation and liquid–gas phase transition in strongly interacting matter composed of α particles

Systems of Bose particles with both repulsive and attractive interactions are studied using the Skyrme-like mean-field model. The phase diagram of such systems exhibits two special lines in the chemical potential-temperature plane: one line which represents the first-order liquid–gas phase transition with the critical end point, and another line which represents the onset of Bose–Einstein condensation. The calculations are made for strongly interacting matter composed of α particles. The phase diagram of this matter is qualitatively similar to that observed for the atomic 4He liquid. The sensitivity of the results to the model parameters is studied. For weak interaction coupling, the critical point is located at the Bose-condensation line.