Utilizing the strong interactions between highly excited Rydberg states in an ultracold atomic gas offers a unique playground to study few and many-body physics. In particular, the off-resonant optical admixture of Rydberg interactions to an atomic ground state, so-called "Rydberg dressing", has been proposed as a source of novel interactions.
I will present our experimental approach of realizing Rydberg-dressed Ising spin interactions in an atomic Mott insulator of Rubidium-87 by off-resonant single-photon coupling to Rydberg p-states. First interferometric measurements on a two-dimensional sample demonstrated versatile control of these interactions, however the coherence of the observed dynamics was limited. In contrast, coherence times are substantially increased in a one-dimensional spin chain, allowing for the detection of interaction-driven coherent collapse and revival dynamics of the magnetization in the chain.
Furthermore, I will present our progress on exploring exotic Rydberg interaction potentials. In particular, we were able to observe "Rydberg macrodimers", molecular bound states between two Rydberg atoms hosted by local minima in the interaction-potential landscape.
Combining the spectroscopic measurements with microscopic readout of the atom loss allows for developing a consistent understanding of relative line strengths, opening the path to controlling molecular photo-association at the ultimate level. Moreover, the high spectral resolution of our measurements enables a precise characterization of the binding potential, challenging state-of-the-art calculations of such interactions.
In future experiments, the loss of atoms at the molecular resonances might provide a way to engineer interesting many-body phases stabilized by dissipation.