Strongly correlated 2D ensembles of bosonic polar molecules

Ultracold molecules are a promising candidate for the quantum simulation of many-body physics. Equipped with long-range interactions and a plethora of long-lived internal states, they can be prepared, controlled and probed using quantum gas microscopy techniques. In recent work, we demonstrated the site-resolved measurement of correlations between ultracold NaRb molecules in a 2D optical lattice [1]. Prepared in an out-of-equilibrium state, the molecules naturally realize the 2D quantum XY model with long-range interactions. The growth of spatial correlations in the thermalization process was read out using a site-resolved Ramsey interferometric technique. Through Floquet engineering using periodic microwave pulse sequences, we also simulated the correlation dynamics of a spin-anisotropic Heisenberg model. We now plan to further cool the molecules through forced evaporation in a bulk trap. Reactive collisional losses between the molecules are heavily suppressed by van der Waals interactions, which are carefully tuned using an external DC electric field. Near a rotational Forster resonance, we demonstrate one-body loss limited molecule lifetimes of several seconds in a bulk trap. Evaporation of the shielded molecules will enable the preparation and study of strongly correlated phases in the extended Bose-Hubbard model.



[1] Christakis, L., Rosenberg, J. S., Raj, R., Chi, S., Morningstar, A., Huse, D. A., Yan, Z. Z., & Bakr, W. S. (2023). Probing site-resolved correlations in a spin system of ultracold molecules. Nature, 614(7946), 64–69.