We demonstrate the experimental realization of a two-qubit M{\o}lmer-S{\o}rensen gate on a magnetic field-insensitive hyperfine transition in 9Be+ ions using microwave-near fields emitted by a single microwave conductor embedded in a surface-electrode ion trap. The design of the conductor was optimized to produce a high oscillating magnetic field gradient at the ion position. The measured gate fidelity is determined to be 98.2±1.2% and is limited by technical imperfections, as is confirmed by a comprehensive numerical error analysis. The conductor design can potentially simplify the implementation of multi-qubit gates and represents a self-contained, scalable module for entangling gates within the quantum CCD architecture for an ion-trap quantum computer.
@article{arxiv.1902.07028,
title = {Integrated $^{9}$Be$^{+}$ multi-qubit gate device for the ion-trap quantum computer},
author = {Henning Hahn and Giorgio Zarantonello and Marius Schulte and Amado Bautista-Salvador and Klemens Hammerer and Christian Ospelkaus},
journal= {arXiv preprint arXiv:1902.07028},
year = {2019}
}