The Lithium-Cesium lab simultaneously creates a Bose-Einstein condensate of bosonic cesium-133 atoms and a degenerate Fermi gas of fermionic lithium-6 atoms. The two atomic samples are spatially overlapped and interact via an interspecies Feshbach resonance near 900 Gauss. This Feshbach resonance gives us the ability to tune the strength of the lithium-cesium interaction from repulsive to attractive across many orders of magnitude. A high-numerical-aperture objective lens enables imaging of the sample at sub-micron resolution, and a digital micromirror device enables the projection of arbitrary repulsive potentials onto the sample.
Lithium-cesium stands out among all the degenerate Bose-Fermi mixtures scientists have managed to create, due to its extremely high boson:fermion mass ratio of ~22:1. The dynamics of the fermionic lithium atoms are thus very fast relative to the dynamics of the cesium Bose-Einstein condensate. This makes it an exceptional platform for studying mediated interactions, a type of physics where two particles of one type interact by exchanging a particle of another type between them.
Other science goals of the experiment include Efimov physics, quantum simulation, Bose-Fermi droplets, and more.