Fermi-surface deformation and collective modes of microwave-shielded polar molecules

Long-range, anisotropic dipole–dipole interactions in ultracold polar molecules open routes toward exotic quantum many-body phases, yet accessing the deeply degenerate interacting regime remains challenging. Here we use microwave shielding to fundamentally modify both the sign and symmetry of dipolar interactions in a fermionic gas of NaK molecules, enabling stable and highly tunable dipolar matter. In particular, microwave dressing can realize effectively negated dipolar interactions with engineered anisotropy, a key ingredient predicted to favor the emergence of chiral topological px +ipy superfluidity in two dimensions.

We will present our progress on evaporative cooling of microwave-shielded NaK molecules into the deeply degenerate regime and report the observation of interaction-driven, symmetry-breaking Fermi-surface deformation as a direct many-body signature of engineered dipolar interactions. We will also show preliminary results on collective modes of the degenerate molecular Fermi gas as a dynamical probe of dipolar many-body physics. Finally, we will report ongoing progress toward trapping highly degenerate fermionic NaK molecules in an optical lattice, providing a pathway to low-entropy lattice dipolar matter and interaction-driven quantum phases.