Transition Slow-Down by Rydberg Interaction of Neutral Atoms and a Fast Controlled-NOT Quantum Gate

TL;DR

This paper introduces the transition slow-down (TSD) effect in Rydberg atoms, enabling a fast and precise controlled-NOT (CNOT) gate that enhances neutral atom quantum computing capabilities.

Contribution

It demonstrates a novel TSD effect in Rydberg atoms and leverages it to implement a rapid, high-fidelity CNOT gate with sub-microsecond duration.

Findings

TSD effect causes a slowdown in Rydberg state transitions.

A CNOT gate with a duration of about 2π/Ω + ε is achieved.

TSD-based CNOT surpasses some existing quantum gate implementations.

Abstract

Exploring controllable interactions lies at the heart of quantum science. Neutral Rydberg atoms provide a versatile route toward flexible interactions between single quanta. Previous efforts mainly focused on the excitation annihilation~(EA) effect of the Rydberg blockade due to its robustness against interaction fluctuation. We study another effect of the Rydberg blockade, namely, the transition slow-down~(TSD). In TSD, a ground-Rydberg cycling in one atom slows down a Rydberg-involved state transition of a nearby atom, which is in contrast to EA that annihilates a presumed state transition. TSD can lead to an accurate controlled-{\footnotesize NOT}~({\footnotesize CNOT}) gate with a sub-$\mu$s duration about $2\pi/\Omega+\epsilon$ by two pulses, where $\epsilon$ is a negligible transient time to implement a phase change in the pulse and $\Omega$ is the Rydberg Rabi frequency. The speedy and accurate TSD-based {\footnotesize CNOT} makes neutral atoms comparable~(superior) to superconducting~(ion-trap) systems.