Controlling a many-body spin system of polar molecules*

Due to their strong, long-range, and tunable dipolar interactions, ultracold molecules in optical lattices are a versatile platform for studying quantum many-body physics. We used Ramsey spectroscopy of rotational states of ultracold KRb molecules to explore the dynamics of a disordered system of interacting spins. In order to understand the microscopic mechanism of contrast decay observed in our recent work with itinerant molecules [1], we performed a systematic investigation of the role of motion on spin dynamics by adjusting the tunneling rate in a three-dimensional optical lattice. We also used Floquet engineering to tune the interactions between molecules, realizing a range of XXZ spin models and studying two-axis twisting mean-field dynamics. Finally, we will present progress towards preparing a deeply degenerate two-dimensional Fermi gas of polar molecules.

 

[1] Li, JR., Matsuda, K., Miller, C, Carroll, A. N., Tobias, W. G., Higgins, J. S., & Ye, J. Tunable itinerant spin dynamics with polar molecules. Nature 614, 70–74 (2023).