Ultracold polar molecules have long been heralded as ideal candidates for exploring a plethora of exotic phenomena in molecular and many-body physics. These include the study of chemistry in the quantum regime, the emulation of strongly-interacting spin models, the production of topological phases, and the exploration of fundamental symmetries. However, in many of these applications, a low-entropy, quantum degenerate gas is required.
In this talk, I will describe the production of a quantum degenerate gas of fermionic potassium-rubidium (KRb) molecules. Through coherent adiabatic association in a deeply degenerate mixture of a rubidium Bose- Einstein condensate and potassium Fermi gas, we produce 25,000 molecules with temperatures below 0.3 times the Fermi temperature. The effects of degeneracy are evident in the molecular momentum distribution, and the gas shows a clear deviation from classical behavior. Finally, we observe a chemical reaction rate that is reduced beyond the Bethe-Wigner threshold law prediction, and we show that this suppression is due to the Pauli pressure of the molecular Fermi gas.