Discriminating the Phase of a Coherent Tone with a Flux-Switchable Superconducting Circuit

Year: 2023

Authors: Di Palma L., Miano A., Mastrovito P., Massarotti D., Arzeo M., Pepe GP., Tafuri F., Mukhanov O.

Autors Affiliation: Univ Napoli Federico II, Dipartimento Fis Ettore Pancini, I-80125 Naples, Italy; SEEQC, Corso Protopisani 70, I-80146 Naples, Italy; Yale Univ, Dept Appl Phys, New Haven, CT 06520 USA; Univ Napoli Federico II, Dipartimento Ingn Elettr & Tecnol Informaz, via Claudio, I-80125 Naples, Italy; UOS Napoli, CNR SPIN, Monte S Angelo,Via Cinthia, I-80126 Naples, Italy; CNR Ist Nazl Ott CNR INO, Largo Enr Fermi 6, I-50125 Florence, Italy; SEEQC, Elmsford, NY 10523 USA.

Abstract: We propose a new phase detection technique based on a flux-switchable superconducting circuit, the Josephson digital phase detector (JDPD), which is capable of discriminating between two phase values of a coherent input tone. When properly excited by an external flux, the JDPD is able to switch from a single-minimum to a double-minima potential and, consequently, relax in one of the two stable configurations depending on the phase sign of the input tone. The result of this operation is digitally encoded in the occupation probability of a phase particle in either of the two JDPD wells. In this work, we demonstrate the working principle of the JDPD up to a frequency of 400 MHz with a remarkable agreement with theoretical expectations. As a future scenario, we discuss the implementation of this technique to superconducting qubit readout. We also examine the JDPD compatibility with the single-flux-quantum architecture, employed to fast-drive and measure the device state.

Journal/Review: PHYSICAL REVIEW APPLIED

Volume: 19 (6)      Pages from: 64025-1  to: 64025-15

More Information: The research activities were also supported by the PNRR MUR project PE0000023-NQSTI and the PNRR MUR project CN_00000013-ICSC. The authors would like to thank D. Yohannes, J. Vivalda, M. Renzullo, and A. Chambal-Jacobs for the fabrication of the samples, and A. Kirichenko, A. Salim, and R. Albu for advice in design. The work was supported by the project Onchip signal generation for superconducting quantum processors (SFQ4QPU) , in the frame of Eurostars CoD 15 Call 2021; the project SQUAD – On-chip control and advanced read-out for superconducting qubit arrays (SQUAD) in the frame of Programme STAR Plus, financially supported by UniNA and Compagnia di San Paolo; and the project Superconducting quantum-classical linked computing systems (SuperLink ) , in the frame of Quan- tERA2 ERANET COFUND in Quantum Technologies.
KeyWords: Harmonic-oscillator; Quantum; Comparator; Device; Qubit
DOI: 10.1103/PhysRevApplied.19.064025

Citations: 2
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