Speaker
Description
Spin mixtures of ultracold fermions are a cornerstone of quantum many-body physics, enabling superfluidity, polaron formation, and rich spin dynamics. Introducing strong, long-range dipolar forces into such mixtures promises even more exotic phases, but has been hampered by the loss of two molecules at short range. Microwave dressing can prevent the gas from the short-range collapse and induce the field-linked scattering resonance. This shield has already stabilised the first shallowly degenerate gas of dipolar fermions, but only with a single internal state, leaving the physics of spin mixtures largely unexplored. Here, we show that introducing a second spin state unlocks a new and simple handle on interactions. In particular, tuning the microwave power sweeps the s-wave interaction from strongly attractive to strongly repulsive, crossing a field-link scattering resonance. This control enables fast s-wave evaporative cooling and opens new routes to stable, strongly interacting dipolar Fermi gases.
