Robust quantum logic in neutral atoms via adiabatic Rydberg dressing

TL;DR

This paper proposes a robust method for implementing high-fidelity controlled-Z gates between neutral-atom qubits using adiabatic Rydberg dressing, effectively reducing motional and Doppler errors.

Contribution

It introduces an adiabatic dressing scheme with a Doppler-free laser configuration that enhances gate robustness against atomic motion errors.

Findings

CZ gate achievable in under 10 microseconds

Error probability estimated around 10^-3

Protocol reduces motional and Doppler errors effectively

Abstract

We study a scheme for implementing a controlled-Z (CZ) gate between two neutral-atom qubits based on the Rydberg blockade mechanism in a manner that is robust to errors caused by atomic motion. By employing adiabatic dressing of the ground electronic state, we can protect the gate from decoherence due to random phase errors that typically arise because of atomic thermal motion. In addition, the adiabatic protocol allows for a Doppler-free configuration that involves counterpropagating lasers in a $\sigma_+/\sigma_-$ orthogonal polarization geometry that further reduces motional errors due to Doppler shifts. The residual motional error is dominated by dipole-dipole forces acting on doubly-excited Rydberg atoms when the blockade is imperfect. For reasonable parameters, with qubits encoded into the clock states of $^{133}$Cs, we predict that our protocol could produce a CZ gate in $<10$ $\mu$s with error probability on the order of $10^{-3}$.