Isobars of an ideal Bose gas within the grand canonical ensemble

초록

We investigate the isobar of an ideal Bose gas confined in a cubic box within the grand canonical ensemble for a large yet finite number of particles, N. After solving the equation of the spinodal curve, we derive precise formulas for the supercooling and the superheating temperatures that reveal an N-1/3 or N-1/4 power correction to the known Bose-Einstein condensation temperature in the thermodynamic limit. Numerical computations confirm the accuracy of our analytical approximation, and further show that the isobar zigzags on the temperature-volume plane if N >= 14 393. In particular, for the Avogadro's number of particles, the volume expands discretely about 10(5) times. Our results quantitatively agree with a previous study on the canonical ensemble within 0.1% error.