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±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 3.8μm. Using the standard protocol for a Rydberg blockade CZ 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.
@article{arxiv.1506.06416,
title = {A Rydberg blockade CNOT gate and entanglement in a 2D array of neutral atom qubits},
author = {K. M. Maller and M. T. Lichtman and T. Xia and Y. Sun and M. J. Piotrowicz and A. W. Carr and L. Isenhower and M. Saffman},
journal= {arXiv preprint arXiv:1506.06416},
year = {2015}
}