Effect of atom motion in Rydberg-atom arrays

Ultracold Rydberg atoms in optical lattices and tweezer arrays are a promising platform to study quantum spin models. Ref. [1] suggests that a two-particle “interaction noise” is required to reproduce their experimentally observed Rydberg-atom dynamics, but it provided only a phenomenological description of the effect. To understand these effects without any fitting or phenomenological assumptions, we calculate dynamics of Rydberg atom spin models including atom motion, using a discrete truncated Wigner approximation. Our calculations reveal that motional effects cause deviations from the nominal quantum Ising model describing the systems. The results semi-quantitatively agree, without fitting, with Ref. [1]’s experiments and noise model. We calculate how motional effects depend on time scale, atomic mass, lattice or microtrap depth, Rydberg interactions, and other important experimental variables, which will allow this theory to guide future experimental design. We show that although trap depth mitigates these decoherence sources, the motional effects are nevertheless relevant for ongoing experiments in microtrap arrays. 

[1] Guardado-Sanchez et al. Phys. Rev. X 8, 021069 (2018)