Colliding clouds of strongly interacting spin-polarized fermions

Understand

Motivated by a recent experiment at MIT, we consider the collision of two clouds of spin-polarized atomic Fermi gases close to a Feshbach resonance.

• We explain why two dilute gas clouds, with underlying attractive interactions between their constituents, bounce off each other in the strongly interacting regime.
• Our hydrodynamic analysis, in excellent agreement with experiment, gives strong evidence for a metastable many-body state with effective repulsive interactions.