• About
  • Advertise
  • Contact
Saturday, May 31, 2025
Manhattan Tribune
  • Home
  • World
  • International
  • Wall Street
  • Business
  • Health
No Result
View All Result
  • Home
  • World
  • International
  • Wall Street
  • Business
  • Health
No Result
View All Result
Manhattan Tribune
No Result
View All Result
Home Science

Fundamental equation of superconducting qubits revised

manhattantribune.com by manhattantribune.com
14 February 2024
in Science
0
Fundamental equation of superconducting qubits revised
0
SHARES
0
VIEWS
Share on FacebookShare on Twitter


Cryogenic microwave setup used for measurements of quantum devices. Credit: Qinu GmbH, qinu.de

Physicists from Forschungszentrum Jülich and the Karlsruhe Institute of Technology have discovered that Josephson tunnel junctions – the fundamental building blocks of superconducting quantum computers – are more complex than previously thought.

Just like the harmonics of a musical instrument, the harmonics are superimposed on the fundamental mode. As a result, corrections can lead to qubits that are two to seven times more stable. The researchers support their findings with experimental evidence from several laboratories around the world, including the University of Cologne, the Ecole Normale Supérieure in Paris and IBM Quantum in New York.

It all started in 2019, when two doctoral students, Dr. Dennis Willsch and Dennis Rieger, studied. students of FZJ and KIT at the time and co-authors of a new article published in Natural physics— had difficulty understanding their experiments using the standard Josephson tunnel junction model. This model earned Brian Josephson the Nobel Prize in Physics in 1973.

Eager to get to the bottom of things, the team led by Professor Ioan Pop examined further data from the École Normale Supérieure in Paris and a 27-qubit device from IBM Quantum in New York, as well as than previously published experimental data. Independently, researchers at the University of Cologne observed similar discrepancies between their data and the standard model.

“Fortunately, Gianluigi Catelani, who was involved in both projects and realized the overlap, brought the research teams together,” recalls Dr. Dennis Willsch from FZ Jülich. “The timing was perfect,” adds Dr. Chris Dickel of the University of Cologne, “since at that time we were exploring very different consequences of the same underlying problem.”

Josephson tunnel junctions consist of two superconductors separated by a thin insulating barrier, and for decades these circuit elements have been described with a simple sinusoidal model (see image below).

Bottom: By exciting superconducting circuits (yellow/blue) with microwave signals (wavy red arrow), researchers can analyze the fundamental equation that describes the circuit’s Josephson tunnel junction. Right part: Research has observed significant deviations (red curve) from the standard sinusoidal model (green curve). Left part: schematic zoom in of a tunnel junction composed of two superconductors (yellow/blue) with a thin insulating barrier between the two. The large conduction channels (red loops) may be responsible for the observed deviations from the standard model. Credit: Dennis Rieger/Patrick Winkel, KIT

However, as the researchers demonstrate, this “standard model” fails to fully describe the Josephson junctions used to construct quantum bits. Instead, an extended model including higher harmonics is needed to describe the tunneling current between the two superconductors. The principle is also found in the field of music. When the string of an instrument is struck, the fundamental frequency is covered by several harmonics.

“It is exciting that the measurements made in the community have reached the level of precision at which we can make these small corrections to a model that has been considered sufficient for over 15 years,” notes Dennis Rieger.

When the four coordinating professors – Ioan Pop from KIT and Gianluigi Catelani, Kristel Michielsen and David DiVincenzo from FZJ – realized the impact of their results, they brought together a broad collaboration of experimentalists, theorists and materials scientists to unite their efforts to present a convincing argument for Josephson’s harmonic model.

In the Natural physics publication, researchers explore the origin and consequences of Josephson harmonics. “As an immediate consequence, we believe that Josephson harmonics will help design better and more reliable quantum bits by reducing errors by up to an order of magnitude, bringing us closer to the dream of a fully universal superconducting quantum computer,” he said. stated the report. conclude two first authors.

More information:
Dennis Willsch et al, Observation of Josephson harmonics in tunnel junctions, Natural physics (2024). DOI: 10.1038/s41567-024-02400-8

Provided by Karlsruhe Institute of Technology

Quote: Fundamental equation for superconducting quantum bits revised (February 14, 2024) retrieved February 14, 2024 from

This document is subject to copyright. Apart from fair use for private study or research purposes, no part may be reproduced without written permission. The content is provided for information only.



Tags: equationfundamentalqubitsrevisedSuperconducting
Previous Post

Researchers are finding that having good neighbors and few large predators makes predatory fish populations more resilient.

Next Post

The study of the morphology and mineralogy of Mars suggests that it may have once experienced active volcanism and crustal recycling.

Next Post
The study of the morphology and mineralogy of Mars suggests that it may have once experienced active volcanism and crustal recycling.

The study of the morphology and mineralogy of Mars suggests that it may have once experienced active volcanism and crustal recycling.

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Category

  • Blog
  • Business
  • Health
  • International
  • National
  • Science
  • Sports
  • Wall Street
  • World
  • About
  • Advertise
  • Contact

© 2023 Manhattan Tribune -By Millennium Press

No Result
View All Result
  • Home
  • International
  • World
  • Business
  • Science
  • National
  • Sports

© 2023 Manhattan Tribune -By Millennium Press