Experimental preparation of $W$ states through frustration on a programmable quantum simulator

Abstract

$W$ states are a central class of multipartite entangled states with applications in quantum information processing, yet their scalable and deterministic preparation remains challenging. Here we propose a protocol based on {\it topological ring frustration}, where an antiferromagnetic ring with an odd number of sites hosts a delocalized excitation corresponding to a $W$ state. We implement this protocol on a Rydberg atom array -- a programmable quantum simulator -- generating $W$ states of up to 11 atoms. Our results demonstrate a fidelity of $\mathcal{F} \approx 0.77$, and numerical simulations indicate scalability to larger system sizes accessible with near-term hardware improvements. To enable certification of these many-body entangled states, we introduce a novel and efficient Bayesian tomography method that, leveraging on classical simulations, enables their certification with a cost that avoids the exponential scaling of full tomography. These results establish topological frustration as a practical mechanism for engineering multipartite entanglement and provide a scalable route toward the certification of correlated quantum many-body states in quantum simulators.