Feshbach spectroscopy and dual-species Bose-Einstein condensation of Na-23-K-39 mixtures
Authors: Schulze T.A., Hartmann T., Voges K.K., Gempel M.W., Tiemann E., Zenesini A., Ospelkaus S.
Autors Affiliation: Leibniz Univ Hannover, Inst Quantenopt, D-30167 Hannover, Germany.
Abstract: We present measurements of interspecies Feshbach resonances and subsequent creation of dual-species Bose-Einstein condensates of Na-23 and K-39. We prepare both optically trapped ensembles in the spin state vertical bar f = 1, m(f) = -1 > and perform atom loss spectroscopy in a magnetic field range from 0 to 700G. 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-39 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 (NaK)-Na-23-K-39 Feshbach molecules.
Journal/Review: PHYSICAL REVIEW A
Volume: 97(2) Pages from: 023623-1 to: 023623-9
KeyWords: QUANTUM LIQUID; GROUND-STATE; NAK; COLLISIONS; MOLECULES; DROPLETS; ATOMS; GASDOI: 10.1103/PhysRevA.97.023623