Scientific Results

A Dual-Species Bose-Einstein Condensate with Attractive Interspecies Interactions

Year: 2020

Authors: Burchianti A., D’Errico C., Prevedelli M., Salasnich L., Ancilotto F., Modugno M., Minardi F., Fort C.

Autors Affiliation: Istituto Nazionale di Ottica, CNR-INO, 50019 Sesto Fiorentino, Italy; LENS and Dipartimento di Fisica e Astronomia, Università di Firenze, 50019 Sesto Fiorentino, Italy; Dipartimento di Fisica e Astronomia, Università di Bologna, 40127 Bologna, Italy; Dipartimento di Fisica e Astronomia ’Galileo Galilei’ and CNISM, Università di Padova, 35131 Padova, Italy; CNR-IOM Democritos, 265–34136 Trieste, Italy; Depto. de Fisíca Teórica e Hist. de la Ciencia, Universidad del Pais Vasco UPV/EHU, 48080 Bilbao, Spain; IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain

Abstract: We report on the production of a 41K-87Rb dual-species Bose–Einstein condensate with tunable interspecies interaction and we study the mixture in the attractive regime; i.e., for negative values of the interspecies scattering length a12. The binary condensate is prepared in the ground state and confined in a pure optical trap. We exploit Feshbach resonances for tuning the value of a12 . After compensating the gravitational sag between the two species with a magnetic field gradient, we drive the mixture into the attractive regime. We let the system evolve both in free space and in an optical waveguide. In both geometries, for strong attractive interactions, we observe the formation of self-bound states, recognizable as quantum droplets. Our findings prove that robust, long-lived droplet states can be realized in attractive two-species mixtures, despite the two atomic components possibly experiencing different potentials.

Journal/Review:

Volume: 5      Pages from: 21-1  to: 21-15

KeyWords: Multicomponent Suerfluids, Mixtures of quantum gases
DOI: https://doi.org/10.3390/condmat5010021