Highly-linear flux-to-voltage transducer based on superconducting quantum interference proximity transistors

Fuente: arXiv
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Auteurs principaux: Greco, Angelo, De Simoni, Giorgio, Giazotto, Francesco
Format: Preprint
Publié: 2026
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author Greco, Angelo
De Simoni, Giorgio
Giazotto, Francesco
author_facet Greco, Angelo
De Simoni, Giorgio
Giazotto, Francesco
contents Superconducting quantum interference devices (SQUIDs) are state-of-the-art in ultra-sensitive magnetometry; however, conventional SQUID devices are fundamentally limited by the inherently nonlinear and periodic nature of their transfer function. Although flux-locked loop (FLL) configurations can mitigate this issue, they introduce electronic complexity and bandwidth constraints that hinder scalability in quantum circuits. In this work, we present an experimental demonstration of the bi-SQUIPT, a flux transducer that modulates the density of states in a proximitized superconducting weak link. The device employs a dual-loop architecture with differential readout, which enables cancellation of non-linearities typical of individual elements, achieving a voltage swing of approximately 120 $μ$V. Measurements yield a spurious-free dynamic range (SFDR) of up to 60 dB, consistent with theoretical predictions and comparable to that of SQUID arrays, while maintaining power dissipation in the femtowatt range. The results further highlight a remarkable operational stability up to 600 mK, positioning the bi-SQUIPT as an enabling technology for high-density cryogenic quantum electronics.
format Preprint
id arxiv_https___arxiv_org_abs_2602_24075
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Highly-linear flux-to-voltage transducer based on superconducting quantum interference proximity transistors
Greco, Angelo
De Simoni, Giorgio
Giazotto, Francesco
Superconductivity
Quantum Physics
Superconducting quantum interference devices (SQUIDs) are state-of-the-art in ultra-sensitive magnetometry; however, conventional SQUID devices are fundamentally limited by the inherently nonlinear and periodic nature of their transfer function. Although flux-locked loop (FLL) configurations can mitigate this issue, they introduce electronic complexity and bandwidth constraints that hinder scalability in quantum circuits. In this work, we present an experimental demonstration of the bi-SQUIPT, a flux transducer that modulates the density of states in a proximitized superconducting weak link. The device employs a dual-loop architecture with differential readout, which enables cancellation of non-linearities typical of individual elements, achieving a voltage swing of approximately 120 $μ$V. Measurements yield a spurious-free dynamic range (SFDR) of up to 60 dB, consistent with theoretical predictions and comparable to that of SQUID arrays, while maintaining power dissipation in the femtowatt range. The results further highlight a remarkable operational stability up to 600 mK, positioning the bi-SQUIPT as an enabling technology for high-density cryogenic quantum electronics.
title Highly-linear flux-to-voltage transducer based on superconducting quantum interference proximity transistors
topic Superconductivity
Quantum Physics
url https://arxiv.org/abs/2602.24075