David Wellnitz (Julich Institute)
Spin-motion coupled dynamics of ultracold molecules
Polar molecules open up new opportunities for quantum simulation of dipolar spin Hamiltonians. In particular, rotational states naturally couple via XY or XXZ interactions, enabling quantum gates in tweezers and the exploration of spin dynamics in optical lattices. Here, I will explore how molecular motion affects these dynamics. In optical lattices, I will discuss how coupling molecular rotations to motion affects spin relaxation dynamics. In deep lattices, many-body spin interactions govern molecular dynamics, whereas in shallow lattices two-body collisions dominate spin relaxation. The transition between the two extremes can be highly peaked, depending on the competition of Ising and exchange interactions. In optical tweezers, rotation-motion coupling induces dephasing that can limit the fidelities of entangling gates. I will discuss experimental collaborations that probe these regimes, and where dynamics can be accurately captured by numerical simulations. These works provide insights into how to simulate and understand spin-motion dynamics in polar molecules for the development of future quantum simulations.