Study of stability of relativistic ideal Bose–Einstein condensates

A relativistic complex scalar boson field at finite temperature T is examined below its critical Bose–Einstein condensation temperature. It is shown that at the same T the state with antibosons has higher entropy, lower Helmholtz free energy and higher pressure than the state without antibosons — but the same Gibbs free energy as it should. This implies that the configuration without antibosons is metastable. Results are generalized for arbitrary d spatial dimensions. -- Highlights: ► A recent study of the relativistic Bose gas based on the Helmholtz free energy is generalized. ► The generalization introduced is in terms of the entropy. ► In addition, the system internal energy and pressure are calculated. ► The study is extended to arbitrary d>0 spatial dimensions.