Yang-Lee circle theorem for an ideal pseudospin-1/2 Bose gas in an external magnetic field - art. no. 046103

The Yang-Lee circle theorem is extended to an ideal pseudospin-1/2 Bose gas in an external magnetic field. It is found that the zeros of the canonical partition function are located on the unit circle in the complex activity plane if the temperature is above the critical temperature of ideal Bose-Ei nstein condensation. No zeros exist if the temperature is below the critica l temperature.