Bose-Einstein condensation in quasi2D trapped gases

TL;DR

This paper explores Bose-Einstein condensation in quasi-2D trapped gases, highlighting the transition from true condensates to quasicondensates and how confinement tuning affects interactions and inelastic processes.

Contribution

It demonstrates the dependence of mean-field interactions on confinement frequency and proposes tunable BEC in quasi-2D gases through this mechanism.

Findings

True condensate exists well below T_c

Quasicondensate with fluctuating phase appears at intermediate temperatures

Adjusting confinement frequency can switch interaction sign and reduce inelastic rates

Abstract

We discuss 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 quasi2D gas is sensitive to the frequency $\omega_0$ of the (tight) confinement in the "frozen" direction, and one can switch the sign of the interaction by changing $\omega_0$. Variation of $\omega_0$ can also reduce the rates of inelastic processes, which opens prospects for tunable BEC in trapped quasi2D gases.