Demonstration of dual Shapiro steps in small Josephson junctions

verfasst von: 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.
Externe Organisation(en): Physikalisch-Technische Bundesanstalt (PTB)
Typ: Preprint
Publikationsdatum: 12.01.2024
Publikationsstatus: Veröffentlicht

BibTeX

@techreport{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",
year = "2024",
month = jan,
day = "12",
language = "Undefined/Unknown",
type = "WorkingPaper",
}