A Rydberg blockade CNOT gate and entanglement in a 2D array of neutral atom qubits

TL;DR

This paper demonstrates high-fidelity two-qubit Rydberg blockade gates and entanglement in a 2D array of neutral atom qubits, achieving the highest Bell state fidelity reported to date without post selection.

Contribution

It presents the first experimental realization of a Rydberg blockade CNOT gate and entanglement in a 2D neutral atom array with optimized conditions for maximum fidelity.

Findings

Bell state fidelity of 0.73 achieved

High-fidelity entanglement in a 2D array

Analysis of AC Stark shift effects

Abstract

We present experimental results on two-qubit Rydberg blockade quantum gates and entanglement in a two-dimensional qubit array. Without post selection against atom loss we achieve a Bell state fidelity of $0.73\pm 0.05$, the highest value reported to date. The experiments are performed in an array of single Cs atom qubits with a site to site spacing of $3.8 ~ \mu\rm m$. Using the standard protocol for a Rydberg blockade C$_Z$ gate together with single qubit operations we create Bell states and measure their fidelity using parity oscillations. We analyze the role of AC Stark shifts that occur when using two-photon Rydberg excitation and show how to tune experimental conditions for optimal gate fidelity.