Feshbach spectroscopy and dual-species Bose-Einstein condensation of ²³Na-³⁹K mixtures

2017/09/30 by Torben A. Schulze, Torsten Hartmann, Kai K. Voges +4 · 1 citation
Physics and Astronomy · #cond-mat.quant-gas

paper · pdf · doi:10.1103/physreva.97.023623

published as Phys. Rev. A 97, 023623 (2018) · 9 pages, 7 figures

arxiv created 2018/06/04 · arxiv updated 2018/06/05

Abstract

We present measurements of interspecies Feshbach resonances and subsequent creation of dual-species Bose-Einstein condensates of ²³Na and ³⁹K. We prepare both optically trapped ensembles in the spin state |f = 1,m_f=-1⟩ and perform atom loss spectroscopy in a magnetic field range from 0 to 700 G. The observed features include several s-wave poles and a zero crossing of the interspecies scattering length as well as inelastic two-body contributions in the M = m_Na+m_K = -2 submanifold. We identify and discuss the suitability of different magnetic field regions for the purposes of sympathetic cooling of \K and achieving dual-species degeneracy. Two condensates are created simultaneously by evaporation at a magnetic field of about 150 G, which provides sizable intra- and interspecies scattering rates needed for fast thermalization. The impact of the differential gravitational sag on the miscibility criterion for the mixture is discussed. Our results serve as a promising starting point for the magnetoassociation into quantum degenerate ²³Na³⁹K Feshbach molecules.

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