Bose-Fermi mixtures revisited A European initiative experimented on Bose-Fermi mixtures to study soliton formation in an attempt to widen the applicability of this technology. Industrial Technologies © Thinkstock Multi-component quantum gases with mixed statistics are at the frontier of research in the field of ultracold atoms. They offer unique experimental possibilities for the exploration of fundamental quantum mechanics and condensed matter physics. The EU-funded project ‘Bright solitons and dynamics in Bose-Fermi mixtures’ (Solinmix) aimed to investigate bright solitary waves of constant shape and speed – known as solitons – in an ultracold Bose-Fermi mixture. The required non-linear interaction is provided by the attraction between the Bose and Fermi components. To date, although theoretically predicted, solitons have not been observed in a Bose-Fermi mixture. Experiments were performed using a BEC condensate mixture of fermionic potassium (40K) and bosonic rubidium (87Rb) isotopes using an atom chip. Among the project’s objectives was to ascertain by experiment under which conditions a Bose-Fermi mixture can be considered as one-dimensional, and develop a new tool for varying atom-atom interaction strengths. It was found that p-wave interactions could be used to create extremely robust bright Bose-Fermi matter-wave solitons that were far more stable than their purely bosonic counterparts. Solinmix results have the potential to be used for the development of sensitive surface probes, paving the way for this technology to be used in the fields of precision measurement and surface science.
