Quantum Microwave Parametric Interferometer

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Quantum Microwave Parametric Interferometer

F. Kronowetter, F. Fesquet, M. Renger, K. Honasoge, Y. Nojiri, K. Inomata, Y. Nakamura, A. Marx, R. Gross, and K.G. Fedorov

Phys. Rev. Applied 20, 024049 – Published 21 August 2023

Abstract

Classical interferometers are indispensable tools for the precise determination of various physical quantities. Their accuracy is bound by the standard quantum limit. This limit can be overcome by using quantum states or nonlinear quantum elements. Here, we present the experimental study of a nonlinear Josephson interferometer operating in the microwave regime. Our quantum microwave parametric interferometer (QUMPI) is based on superconducting flux-driven Josephson parametric amplifiers combined with linear microwave elements. We perform a systematic analysis of the implemented QUMPI. We find that its interferometric power exceeds the shot-noise limit and observe sub-Poissonian photon statistics in the output modes. Furthermore, we identify a low-gain operation regime of the QUMPI that is essential for optimal quantum measurements in quantum illumination protocols.

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Received 6 April 2023
Revised 28 July 2023
Accepted 3 August 2023

DOI:https://doi.org/10.1103/PhysRevApplied.20.024049

Physics Subject Headings (PhySH)

Nonlinear optics Optoelectronics Quantum metrology Superconducting quantum optics

Josephson junctions Optical parametric oscillators & amplifiers

Microwave techniques Optical interferometry

Quantum Information, Science & TechnologyAtomic, Molecular & OpticalCondensed Matter, Materials & Applied Physics

Authors & Affiliations

F. Kronowetter ^1,2,3,*, F. Fesquet^1,2, M. Renger^1,2, K. Honasoge^1,2, Y. Nojiri^1,2, K. Inomata ^4,5, Y. Nakamura ^4,6, A. Marx¹, R. Gross ^1,2,7, and K.G. Fedorov^1,2,†

¹Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching 85748, Germany
²School of Natural Sciences, Technische Universität München, Garching 85748, Germany
³Rohde & Schwarz GmbH & Co. KG, Munich 81671, Germany
⁴RIKEN Center for Quantum Computing (RQC), Wako, Saitama 351-0198, Japan
⁵National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan
⁶Department of Applied Physics, Graduate School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
⁷Munich Center for Quantum Science and Technology (MCQST), Munich 80799, Germany

^*fabian.kronowetter@wmi.badw.de
^†kirill.fedorov@wmi.badw.de

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Vol. 20, Iss. 2 — August 2023

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Physical Review Applied