Identification of collisional resonances and three-body universality based on an ultracold mixture of Li-6 and Cs-133 atoms

One unique feature about ultracold atom experiments is that we are able to control how atoms interact. When two atoms move towards each other, their scattering wavefunction can couple to a bound state near the scattering continuum, and the scattering amplitude can develop a resonant enhancement, which we called a Feshbach resonance. Here we report our observations on the Feshbach resonances in an ultracold mixture of fermionic Li-6 and bosonic Cs-133 atoms. Those resonances provides us essential information to control the interactions between the two atomic species, which opens up many exciting research fronts, especially to explore the three-body universality of the mixture.