Atoms Interlinked by Light: Programmable Interactions and Entanglement

Scalable generation of entanglement among cold atoms is a crucial capability for applications ranging from quantum-enhanced measurement to quantum computation. A powerful approach to generating collective entanglement is to couple many atoms to a single mode of light that mediates interactions. I will report on advances in programming the graph of interactions [1] and entanglement [2] in an array of atom clouds trapped in an optical cavity. For our system of spin-1 atoms, the cavity-mediated interactions induce spin-nematic squeezing via the formation of correlated atom pairs. Combining such global squeezing with local spin rotations provides flexible control over the network of entanglement, as we illustrate by preparing independent locally squeezed states, a two-mode entangled state exhibiting Einstein-Podolsky-Rosen steering, and a four-mode square cluster state. Our approach generalizes to preparing arbitrary continuous-variable graph states as resources for advanced quantum sensing protocols and measurement-based quantum computation.

[1] A. Periwal, E. S. Cooper, P. Kunkel, J. F. Wienand, E. J. Davis, and M. Schleier-Smith. "Programmable Interactions and Emergent Geometry in an Array of Atom Clouds," Nature 600, 630-635 (2021).

[2] E. S. Cooper, P. Kunkel, A. Periwal, and M. Schleier-Smith. "Engineering Graph States of Atomic Ensembles by Photon-Mediated Entanglement," arXiv:2212.11961[quant-ph] (2022).