Efficient Production of Large 39K Bose-Einstein Condensates

TL;DR

This paper presents an efficient experimental method for producing large 39K Bose-Einstein condensates using sympathetic cooling with 87Rb and a large optical dipole trap, enabling precise control of interactions via Feshbach resonance.

Contribution

The paper introduces a novel combined cooling approach and trap configuration for large 39K BECs, with tunable interactions using a broad Feshbach resonance.

Findings

Produced over 4x10^5 39K atoms in BEC

Achieved quasi-pure 87Rb condensates of over 8x10^5 atoms

Demonstrated control of interactions via Feshbach resonance

Abstract

We describe an experimental setup and the cooling procedure for producing 39K Bose-Einstein condensates of over 4x10^5 atoms. Condensation is achieved via a combination of sympathetic cooling with 87Rb in a quadrupole-Ioffe-configuration (QUIC) magnetic trap, and direct evaporation in a large volume crossed optical dipole trap, where we exploit the broad Feshbach resonance at 402 G to tune the 39K interactions from weak and attractive to strong and repulsive. In the same apparatus we create quasi-pure 87Rb condensates of over 8x10^5 atoms.