Tomohisa Yoda | Searcharxiv

arXiv2023

Coherent excitation of three-atom entangled states near a two-body Förster resonance

We experimentally study three-body energy exchange during Rydberg excitation near a two-body Förster resonance. By varying the excitation pulse duration or Rabi frequency, we control the process that causes the exchange. We demonstrate the coherence of excitation to three-atom entangled states using an optical rotary echo technique, and compare with a model for excitation in a three-atom basis. Our results suggest a robust way to implement a three-body entangling operation.

physics.atom-ph↗

arXiv2022

Quantifying the impact of state mixing on the Rydberg excitation blockade

The Rydberg excitation blockade has been at the heart of an impressive array of recent achievements; however, state-mixing interactions can compromise its efficiency. When ultracold atoms are excited to Rydberg states near Förster resonance, up to $\sim 50\%$ of atoms can be found in dipole coupled product states within tens of ns after excitation. There has been disagreement in the literature regarding the mechanism by which this mixing occurs. We use state-selective field ionization spectroscopy to measure, on a shot-by-shot basis, the distribution of Rydberg states populated during narrowband laser excitation. Our method allows us to both determine the number of additional Rydberg excitations added by each mixing event, and to quantify the extent to which state mixing ``breaks'' the blockade. For excitation of ultracold rubidium atoms to $nD_{5/2}$ states, we find that the mixing is consistent with a three-body process, except near exact Förster resonance.

physics.atom-ph↗