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

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.

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Cited by in corpus (4)

• Mitigating Errors on Superconducting Quantum Processors through Fuzzy Clustering
• Detector of microwave photon pairs based on a Josephson photomultiplier
• Simulation of a rapid qubit readout dependent on the transmission of a single fluxon
• On-chip microwave coherent source with in-situ control of the photon number distribution