On the Stability of the Repulsive Fermi Gas with Short-Range Interactions

We investigate the stability of a uniform spin-balanced repulsive Fermi gas with short-range interactions. When the atom loss is dominated by background gas collisions, we observe isoenthalpic heating, the quantum Joule-Thomson effect of a nearly ideal Fermi gas. At stronger interactions, we observe the threshold law for three-body recombination with two indistinguishable fermions, i.e. the linear dependence of the three-body loss coefficient, K₃, on kinetic energy. We also measure the scaling relation between K₃ and the two-body scattering length, K₃ ∝ a⁶ across more than three decades.