Observation of p-wave interactions between fermions in a deep optical lattice

We report the first measurements of the energy spectrum of p-wave interacting fermions in a three-dimensional optical lattice. On-site p-wave interactions between a pair of ultracold spin-polarized fermionic atoms in the lattice are directly observed via RF spectroscopy. We control the interaction strength via a magnetic field and probe the interactions on both the repulsive and attractive side of a magnetic Feshbach resonance and reach the unitary regime. Measured energies are compared to solutions of two p-wave interacting particles in a simple harmonic trap. Coherent state manipulation between two free atoms and a strongly interacting doublon state is also demonstrated; wave-function overlap is extracted from the measured Rabi frequency. The measured lifetime of two interacting fermions is observed to be up to ten times larger than that of a free-space dimer. Introducing p-wave interactions into optical lattices may enable the experimental realization of new phases of matter, as well as the simulation of orbital dynamics in natural materials.