Demonstration of dual Shapiro steps in small Josephson junctions

authored by: Fabian Kaap, Christoph Kissling, Victor Gaydamachenko, Lukas Grünhaupt, Sergey Lotkhov
Abstract: Bloch oscillations in small Josephson junctions were predicted theoretically as the quantum dual to Josephson oscillations. A significant consequence of this prediction is the emergence of quantized current steps, so-called dual Shapiro steps, when synchronizing Bloch oscillations to an external microwave signal. These steps potentially enable a fundamental standard of current $I$, defined via the frequency $f$ of the external signal and the elementary charge $e$, $I=\pm n \times 2ef$, where $n$ is a natural number. Here, we realize this fundamental relation by synchronizing the Bloch oscillations in small Al/AlO$_\mathrm{x}$/Al Josephson junctions to sinusoidal drives with frequencies varying from $1$ to $6\:\mathrm{GHz}$ and observe dual Shapiro steps up to $I\approx 3 \: \mathrm{nA}$. Inspired by today's voltage standards and to further confirm the duality relation, we investigate a pulsed drive regime, which is dual to the single flux quantum mode of Josephson oscillations, and observe a similar asymmetric pattern of dual Shapiro steps. This work confirms quantum duality effects in Josephson junctions and paves the way towards a range of applications in quantum metrology based on well-established fabrication techniques and straightforward circuit design.
External Organisation(s): National Metrology Institute of Germany (PTB)
Type: Article
Journal: Nature Communications
Volume: 15
ISSN: 2041-1723
Publication date: 09.10.2024
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Physics and Astronomy(all), Chemistry(all), Biochemistry, Genetics and Molecular Biology(all)
Electronic version(s): https://doi.org/10.1038/s41467-024-53011-z (Access: Open)

BibTeX

@article{d5744771cd14404eaa5b6b629e5580af,
title = "Demonstration of dual Shapiro steps in small Josephson junctions",
abstract = " Bloch oscillations in small Josephson junctions were predicted theoretically as the quantum dual to Josephson oscillations. A significant consequence of this prediction is the emergence of quantized current steps, so-called dual Shapiro steps, when synchronizing Bloch oscillations to an external microwave signal. These steps potentially enable a fundamental standard of current $I$, defined via the frequency $f$ of the external signal and the elementary charge $e$, $I=\pm n \times 2ef$, where $n$ is a natural number. Here, we realize this fundamental relation by synchronizing the Bloch oscillations in small Al/AlO$_\mathrm{x}$/Al Josephson junctions to sinusoidal drives with frequencies varying from $1$ to $6\:\mathrm{GHz}$ and observe dual Shapiro steps up to $I\approx 3 \: \mathrm{nA}$. Inspired by today's voltage standards and to further confirm the duality relation, we investigate a pulsed drive regime, which is dual to the single flux quantum mode of Josephson oscillations, and observe a similar asymmetric pattern of dual Shapiro steps. This work confirms quantum duality effects in Josephson junctions and paves the way towards a range of applications in quantum metrology based on well-established fabrication techniques and straightforward circuit design. ",
keywords = "cond-mat.mes-hall, cond-mat.supr-con, quant-ph",
author = "Fabian Kaap and Christoph Kissling and Victor Gaydamachenko and Lukas Gr{\"u}nhaupt and Sergey Lotkhov",
note = "Publisher Copyright: {\textcopyright} The Author(s) 2024.",
year = "2024",
month = oct,
day = "9",
doi = "10.1038/s41467-024-53011-z",
language = "English",
volume = "15",
journal = "Nature Communications",
issn = "2041-1723",
publisher = "Nature Publishing Group",
number = "1",
}