Prof. Ebubechukwu Ilo-Okeke 
Department of Physics
William & Mary

Abstract

Entangling gates are the fundamental building blocks of quantum computation, yet their realization in neutral atom systems remains challenging due to tradeoffs between speed, fidelity, and scalability. In this talk, I will present a new approach to implementing a fast, deterministic entangling gate for two or multiple neutral atom qubits operating in the ultrastrong coupling regime. Our method exploits the direct interaction of qubits with a shared bosonic mode, where counter-rotating terms, typically neglected under the rotating-wave approximation, play a central role. We show that the gate naturally disentangles the atomic and bosonic degrees of freedom at periodic times, while leaving behind robust qubit–qubit correlations. By tuning the coupling strength, the protocol prepares a range of highly nonclassical states, including maximally entangled Bell states, Greenberger–Horne–Zeilinger (GHZ) states, and Schrödinger-cat states. Importantly, the gate time is inversely proportional to the coupling strength, enabling ultrafast operation that outpaces decoherence. I will discuss the physical intuition behind the mechanism, and potential experimental realizations in neutral atom platforms. This work points to a practical path for achieving high-fidelity entangling gates that are both scalable and resilient, advancing the frontier of neutral atom quantum computing.

Prof. Ilo-Okeke's Website