Molecular Quantum Matter

It has been a long quest in ultracold quantum science to realize many-body systems with strong and tunable long-range interactions that reach beyond the typical contact interactions of ultracold atoms. In this talk, I will report on recent advances from our lab that have led to the creation of ultracold gases of dipolar NaCs molecules [1-3]. NaCs is a bosonic molecule with a large dipole moment (4.6 Debye). The resulting dipolar interactions are highly controllable and allow us to reach an effective interaction range that is significantly larger than typical interparticle spacings, giving us access deep into the strongly interacting regime. I will report on microwave shielding in NaCs, a technique that protects molecules from lossy inelastic collisions and increases the lifetime of our molecular samples by more than a factor of 100. We now observe lifetimes on the scale of one second, which makes ultracold gases of NaCs a "fully usable" quantum liquid. This new form of dipolar quantum matter presents us with a wide range of opportunities to study new emergent quantum phases in 2D (quantum crystals, supersolidity, hexatic phases), realize extended Hubbard models (including Mott insulators with fractional filling), and open up new avenues for quantum simulation of frustrated spin systems.