Published February 23, 2024 | Version in press
Journal Article Open

Non-classical microwave–optical photon pair generation with a chip-scale transducer

Abstract

Modern computing and communication technologies such as supercomputers and the Internet are based on optically connected networks of microwave-frequency information processors. An analogous architecture has been proposed for quantum networks, using optical photons to distribute entanglement between remote superconducting quantum processors. Here we report a step towards such a network by observing non-classical correlations between photons in an optical link and a superconducting quantum device. We generate these states of light through a spontaneous parametric down-conversion process in a chip-scale piezo-optomechanical transducer, and we measure a microwave–optical cross-correlation exceeding the Cauchy–Schwarz classical bound for thermal states. As further evidence of the non-classical character of the microwave–optical photon pairs, we observe antibunching in the microwave state conditioned on detection of an optical photon. Such a transducer can be readily connected to an independent superconducting qubit module and serve as a key building block for optical quantum networks of microwave-frequency qubits.

Copyright and License

© The Author(s), under exclusive licence to Springer Nature Limited 2024.

Acknowledgement

We thank M. Mirhosseini, M. Kalaee, A. Sipahigil and J. Banker for contributions in the early stages of this work, E. Kim, A. Butler, G. Kim, S. Sonar, U. Hatipoglu and J. Rochman for helpful discussions and B. Baker and M. McCoy for experimental support. We thank MIT Lincoln Laboratories for providing the travelling-wave parametric amplifier used in the microwave readout chain in our experimental set-up. NbN deposition during the fabrication process was performed at the Jet Propulsion Laboratory. This work was supported by the ARO/LPS Cross Quantum Technology Systems program (grant W911NF-18-1-0103), the US Department of Energy Office of Science National Quantum Information Science Research Centers (Q-NEXT, award DE-AC02-06CH11357), the Institute for Quantum Information and Matter (IQIM) and the NSF Physics Frontiers Center (grant PHY-1125565) with support from the Gordon and Betty Moore Foundation, the Kavli Nanoscience Institute at Caltech and the AWS Center for Quantum Computing. L.J. acknowledges support from the AFRL (FA8649-21-P-0781), NSF (ERC-1941583, OMA-2137642) and the Packard Foundation (2020-71479). S.M. acknowledges support from the IQIM Postdoctoral Fellowship.

Contributions

These authors contributed equally: Srujan Meesala, Steven Wood, David Lake.

S.M., S.W., D.L. and O.P. came up with the concept, S.M., S.W. and D.L. planned the experiment. S.M., S.W., D.L. and P.C. designed the device. S.M. and S.W. performed device fabrication with help from A.D.B. and M.D.S. for NbN deposition. M.D.S. provided the single photon detector used in the experiments. S.M., S.W. and D.L. performed the measurements and analysed the data. S.M., D.L., C.Z. and L.J. developed the theoretical model. O.P. supervised the project. All authors contributed to the writing of the manuscript.

Data Availability

Data shown in the main text and Supplementary Information are available on Zenodo50Source data are provided with this paper.

Conflict of Interest

O.P. is currently employed by Amazon Web Services (AWS) as Director of their quantum hardware program. AWS provided partial funding support for this work through a sponsored research grant.

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Additional details

Identifiers

ISSN
1745-2481
URL
https://rdcu.be/dzGnE

Funding

United States Army Research Office
W911NF-18-1-0103
United States Department of Energy
DE-AC02-06CH11357
California Institute of Technology
Institute for Quantum Information and Matter
National Science Foundation
PHY-1125565
Gordon and Betty Moore Foundation
California Institute of Technology
Kavli Nanoscience Institute
California Institute of Technology
AWS Center for Quantum Computing
Amazon (United States)
United States Air Force Research Laboratory
FA8649-21-P-0781
National Science Foundation
EEC-1941583
National Science Foundation
OSI-2137642
David and Lucile Packard Foundation
2020-71479

Caltech Custom Metadata

Caltech groups
Kavli Nanoscience Institute, Institute for Quantum Information and Matter, AWS Center for Quantum Computing