The effect of atom motion in Rydberg atom quantum simulators of spin models

Rydberg atom arrays are a widely used platform to simulate lattice spin models, but some experiments reveal decoherences that we do not fully understand. Inspired by strong decoherence observed by recent experiments [Guardado-Sanchez et al. Phys. Rev. X 8, 021069 (2018)] that conjectured this to be caused by atom motion, we consider the coupling of atom motion to the spin dynamics. Our results show that, in ongoing experiments with either optical lattices or microtraps, atom motion causes decoherence that can be significant. This decoherence comes from the initial spread of atoms' positions and momenta, as well as the interaction-induced motion during the dynamics. We suggest possible ways to reduce this type of decoherence, such as using heavier atoms or deeper traps.