High-fidelity parallel entangling gates on a neutral-atom quantum computer

Creators: Evered, Simon J.; Bluvstein, Dolev; Kalinowski, Marcin; Ebadi, Sepehr; Manovitz, Tom; Zhou, Hengyun; Li, Sophie H.; Geim, Alexandra A.; Wang, Tout T.; Maskara, Nishad; Levine, Harry; Semeghini, Giulia; Greiner, Markus; Vuletić, Vladan; Lukin, Mikhail D.

Abstract

The ability to perform entangling quantum operations with low error rates in a scalable fashion is a central element of useful quantum information processing1. Neutral-atom arrays have recently emerged as a promising quantum computing platform, featuring coherent control over hundreds of qubits2,3 and any-to-any gate connectivity in a flexible, dynamically reconfigurable architecture4. The main outstanding challenge has been to reduce errors in entangling operations mediated through Rydberg interactions5. Here we report the realization of two-qubit entangling gates with 99.5% fidelity on up to 60 atoms in parallel, surpassing the surface-code threshold for error correction6,7. Our method uses fast, single-pulse gates based on optimal control8, atomic dark states to reduce scattering9 and improvements to Rydberg excitation and atom cooling. We benchmark fidelity using several methods based on repeated gate applications10,11, characterize the physical error sources and outline future improvements. Finally, we generalize our method to design entangling gates involving a higher number of qubits, which we demonstrate by realizing low-error three-qubit gates12,13. By enabling high-fidelity operation in a scalable, highly connected system, these advances lay the groundwork for large-scale implementation of quantum algorithms14, error-corrected circuits7 and digital simulations15.

Copyright and License

© The Author(s) 2023. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

Acknowledgement

We thank S. Hollerith for discussions on error contributions from motional states and M. Cain for insights on atomic dark states. We further thank M. Abobeih, H. Bernien, N.-C. Chiu, S. Geier, J. Guo, A. Keesling, H. Pichler and P. Stroganov for useful discussions, technical support and careful reading of the manuscript. We also thank QuEra Computing and IPG Photonics and in particular N. Gemelke, M.-G. Hu, M. Kwon and A. Lukin for support in the development and testing of the high-power 1,013-nm Rydberg laser. We acknowledge financial support from the U.S. Department of Energy (DOE Quantum Systems Accelerator Center, contract numbers 7568717 and DE-SC0021013), the Center for Ultracold Atoms, the National Science Foundation, the Army Research Office MURI (grant number W911NF-20-1-0082) and the DARPA ONISQ programme (grant number W911NF2010021). S.J.E. acknowledges support from the National Defense Science and Engineering Graduate (NDSEG) fellowship. D.B. acknowledges support from the NSF Graduate Research Fellowship Program (grant DGE1745303) and the Fannie and John Hertz Foundation. T.M. acknowledges support from the Harvard Quantum Initiative Postdoctoral Fellowship in Science and Engineering. N.M. acknowledges support by the Department of Energy Computational Science Graduate Fellowship under award number DE-SC0021110.

Contributions

These authors contributed equally: Simon J. Evered, Dolev Bluvstein, Marcin Kalinowski.

S.J.E., D.B., M.K., S.E., T.M., H.Z., S.H.L. and A.A.G. contributed to the building of the experimental setup, performed the measurements and analysed the data. M.K. developed the two-qubit gate schemes and performed theoretical analysis. N.M. and M.K. developed the multi-qubit gate schemes. T.T.W., H.L. and G.S. contributed to initial developments and insights into gate error sources. All work was supervised by M.G., V.V. and M.D.L. All authors discussed the results and contributed to the manuscript.

Data Availability

The data that support the findings of this study are available from the corresponding author on reasonable request.

Conflict of Interest

M.G., V.V. and M.D.L. are co-founders and shareholders and H.Z. is an employee of QuEra Computing.

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