Growth dynamics of a Bose-Einstein condensate in a dimple trap without cooling

TL;DR

This paper investigates how a localized attractive potential, or dimple, can induce Bose-Einstein condensation in a harmonic trap without traditional cooling, analyzing thermodynamics and dynamics through theory and experiments.

Contribution

It demonstrates the formation of a Bose-Einstein condensate via a dimple trap without cooling, providing a detailed theoretical and experimental analysis of the process.

Findings

Optimal dimple depth maximizes condensate fraction

Good agreement with Hartree-Fock equilibrium theory

Quantum kinetic theory accurately describes non-equilibrium dynamics

Abstract

We study the formation of a Bose-Einstein condensate in a cigar-shaped three-dimensional harmonic trap, induced by the controlled addition of an attractive "dimple" potential along the weak axis. In this manner we are able to induce condensation without cooling due to a localized increase in the phase space density. We perform a quantitative analysis of the thermodynamic transformation in both the sudden and adiabatic regimes for a range of dimple widths and depths. We find good agreement with equilibrium calculations based on self-consistent semiclassical Hartree-Fock theory describing the condensate and thermal cloud. We observe there is an optimal dimple depth that results in a maximum in the condensate fraction. We also study the non-equilibrium dynamics of condensate formation in the sudden turn-on regime, finding good agreement for the observed time dependence of the condensate fraction with calculations based on quantum kinetic theory.