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 σ+/σ− 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 133Cs, we predict that our protocol could produce a CZ gate in <10μs with error probability on the order of 10−3.
@article{arxiv.1411.2622,
title = {Robust quantum logic in neutral atoms via adiabatic Rydberg dressing},
author = {Tyler Keating and Robert L. Cook and Aaron Hankin and Yuan-Yu Jau and Grant W. Biedermann and Ivan H. Deutsch},
journal= {arXiv preprint arXiv:1411.2622},
year = {2015}
}