Bose-Einstein Condensation in Quasi-2D Trapped Gases

Abstract

We discuss Bose-Einstein condensation (BEC) in quasi-2D trapped gases and find that well below the transition temperature ${T}_{c}$ the equilibrium state is a true condensate, whereas at intermediate temperatures $T<{T}_{c}$ one has a quasicondensate (condensate with fluctuating phase). The mean-field interaction in a quasi-2D gas is sensitive to the frequency ${\ensuremath{\omega}}_{0}$ of the (tight) confinement in the ``frozen'' direction, and one can switch the sign of the interaction by changing ${\ensuremath{\omega}}_{0}$. Variation of ${\ensuremath{\omega}}_{0}$ can also reduce the rates of inelastic processes. This offers promising prospects for tunable BEC in trapped quasi-2D gases.