2-STEP CONDENSATION OF THE IDEAL BOSE-GAS IN HIGHLY ANISOTROPIC TRAPS

The ideal Bose gas in a highly anisotropic harmonic potential is studi ed. It is found that Bose-Einstein condensation occurs in two distinct steps as the temperature is lowered. In the first step the specific h eat shows a sharp feature, but the system still occupies many one-dime nsional quantum states. In the second step, at a significantly lower t emperature, the ground state becomes macroscopically occupied. It shou ld be possible to verify these predictions using present-day atom trap s. The two-step behavior can occur in a rather general class of anisot ropic traps, including the box potential.