High-fidelity Rydberg quantum gate via a two-atom dark state

TL;DR

This paper introduces a high-fidelity two-qubit quantum gate for neutral atoms using a two-atom dark state involving Rydberg states, which is robust, scalable, and minimizes decoherence.

Contribution

It presents a novel adiabatic gate scheme leveraging a two-atom dark state with optimal error scaling and resilience to interaction variations.

Findings

Error probability scales as (Bτ)^{-1} with interaction strength and lifetime.

Gate is robust against interaction strength variations.

No atomic motion or decoherence from internal-translational entanglement.

Abstract

We propose a two-qubit gate for neutral atoms in which one of the logical state components adiabatically follows a two-atom dark state formed by the laser coupling to a Rydberg state and a strong, resonant dipole-dipole exchange interaction between two Rydberg excited atoms. Our gate exhibits optimal scaling of the intrinsic error probability $E \propto (B\tau)^{-1}$ with the interatomic interaction strength $B$ and the Rydberg state lifetime $\tau$. Moreover, the gate is resilient to variations in the interaction strength, and even for finite probability of double Rydberg excitation, the gate does not excite atomic motion and experiences no decoherence due to internal-translational entanglement.