Fast Quantum Gates for Neutral Atoms Separated by a Few Tens of Micrometers

TL;DR

This paper proposes a theoretical scheme for fast, high-fidelity two-qubit gates between neutral atoms separated by over 20 micrometers, utilizing resonant dipole-dipole interactions with optimal control.

Contribution

It introduces a novel protocol that extends interaction range and achieves high fidelity, surpassing traditional blockade-based gates using Rydberg states.

Findings

Achieves gate fidelities comparable to existing methods

Extends effective interaction range by an order of magnitude

Enables entanglement beyond the blockade radius

Abstract

We present a theoretical scheme for a family of fast and high-fidelity two-qubit iSWAP gates between neutral atoms separated by more than 20 um, enabled by resonant dipole-dipole spin-exchange interactions between Rydberg states. The protocol harnesses coherent excitation-exchange-deexcitation dynamics between the qubit and the Rydberg states within a single and smooth laser pulse, in the presence of strong dipole-dipole interactions. We utilize optimal control methods to achieve theoretical gate fidelities and durations comparable to blockade-based gates in the presence of relevant noise, while extending the effective interaction range by an order of magnitude. This enables entanglement well beyond the blockade radius, offering a route toward fast, high-connectivity quantum processors.