Nav: Home

Essential quantum computer component downsized by two orders of magnitude

November 14, 2017

Qubits, or quantum bits, are the key building blocks that lie at the heart of every quantum computer. In order to perform a computation, signals need to be directed to and from qubits. At the same time, these qubits are extremely sensitive to interference from their environment, and need to be shielded from unwanted signals, in particular from magnetic fields. It is thus a serious problem that the devices built to shield qubits from unwanted signals, known as nonreciprocal devices, are themselves producing magnetic fields. Moreover, they are several centimeters in size, which is problematic, given that a large number of such elements is required in each quantum processor. Now, scientists at the Institute of Science and Technology Austria (IST Austria), simultaneously with competing groups in Switzerland and the United States, have decreased the size of nonreciprocal devices by two orders of magnitude. Their device, whose function they compare to that of a traffic roundabout for photons, is only about a tenth of a millimeter in size, and--maybe even more importantly--it is not magnetic. Their study was published in the open access journal Nature Communications.

When researchers want to receive a signal, for instance a microwave photon, from a qubit, but also prevent noise and other spurious signals from traveling back the same way towards the qubit, they use nonreciprocal devices, such as isolators or circulators. These devices control the signal traffic, similar to the way traffic is regulated in everyday life. But in the case of a quantum computer, it is not cars that cause the traffic but photons in transmission lines. "Imagine a roundabout in which you can only drive counterclockwise", explains first author Dr. Shabir Barzanjeh, who is a postdoc in Professor Johannes Fink's group at IST Austria. "At exit number one, at the bottom, there is our qubit. Its faint signal can go to exit number two at the top. But a signal coming in from exit number two cannot travel the same path back to the qubit. It is forced to travel in a counterclockwise manner, and before it reaches exit one, it encounters exit three. There, we block it and keep it from harming the qubit."

The 'roundabouts' the group has designed consist of aluminum circuits on a silicon chip and they are the first to be based on micromechanical oscillators: Two small silicon beams oscillate on the chip like the strings of a guitar and interact with the electrical circuit. These devices are tiny in size--only about a tenth of a millimeter in diameter--, one of the major advantages the new component has over its traditional predecessors, which were a few centimeters wide.

Currently, only a few qubits have been used to test the principles of quantum computers, but in the future, thousands or even millions of qubits will be connected together, and many of these qubits will require their own circulator. "Imagine building a processor that has millions of such centimeter-size components. It would be enormous and impractical," says Shabir Barzanjeh. "Using our nonmagnetic and very compact on-chip circulators instead makes life a lot easier." Yet some hurdles need to be overcome before the devices will be used for this specific application. For example, the available signal bandwidth is currently still quite small, and the required drive powers might harm the qubits. However, the researchers are confident that these problems will turn out to be solvable.

Professor Johannes Fink joined IST Austria in the beginning of 2016. He and his group study quantum physics in electrical, mechanical and optical chip-based devices with the main objective of advancing and integrating quantum technology. Earlier this year, he received a prestigious ERC Starting Grant for his project to develop a fiber optic transceiver for superconducting qubits, as well as a research grant from the Swiss NOMIS foundation. Dr. Shabir Barzanjeh was awarded a Marie Sk?odowsa-Curie fellowship to work at IST Austria. His main interests are in circuit quantum electrodynamics and optomechanics. From February 12 to 14, 2018, Johannes Fink und Shabir Barzanjeh will host the international conference „Frontiers of Circuit QED and Optomechanics" (FCQO 2018) in Klosterneuburg with the aim to bring together leading scientists in the field. Registration is already open: https://ist.ac.at/fcqo18
-end-
IST Austria

The Institute of Science and Technology (IST Austria) is a PhD granting research institution located in Klosterneuburg, 18 km from the center of Vienna, Austria. Inaugurated in 2009, the Institute is dedicated to basic research in the natural and mathematical sciences. IST Austria employs professors on a tenure-track system, postdoctoral fellows, and doctoral students at its international graduate school. While dedicated to the principle of curiosity-driven research, the Institute owns the rights to all scientific discoveries and is committed to promote their use. The first president of IST Austria is Thomas A. Henzinger, a leading computer scientist and former professor at the University of California in Berkeley, USA, and the EPFL in Lausanne, Switzerland. http://www.ist.ac.at

Institute of Science and Technology Austria

Related Magnetic Fields Articles:

New metrology technique measures electric fields
It is crucial that mobile phones and other wireless devices -- so prevalent today -- have accurate and traceable measurements for electric fields and radiated power.
First direct exploration of magnetic fields in the upper solar atmosphere
Scientists have explored the magnetic field in upper solar atmosphere by observing the polarization of ultraviolet light with the CLASP sounding rocket experiment during its 5-minute flight in space on Sept.
New method can model chemistry in extreme magnetic fields of white dwarfs
Approximately 10-20 percent of white dwarfs exhibit strong magnetic fields, which can reach up to 100,000 tesla.
Researchers control soft robots using magnetic fields
Engineering researchers have made a fundamental advance in controlling so-called soft robots, using magnetic fields to remotely manipulate microparticle chains embedded in soft robotic devices.
Steering towards grazing fields
It makes sense that a 1,200 pound Angus cow would place quite a lot of pressure on the ground on which it walks.
Researchers propose technique for measuring weak or nonexistent magnetic fields
Researchers at the University of Iowa have proposed a new approach to sampling materials with weak or no magnetic fields.
Magnetic fields at the crossroads
Almost all information that exists in contemporary society is recorded in magnetic media, like hard drive disks.
Researchers coax particles to form vortices using magnetic fields
Researchers at Argonne created tiny swirling vortices out of magnetic particles, providing insight into the behavior that governs such systems -- which opens up new opportunities for materials and devices with new properties.
Earth's magnetic fields could track ocean heat, NASA study proposes
As Earth warms, much of the extra heat is stored in the planet's ocean.
Simulations by PPPL physicists suggest that magnetic fields can calm plasma instabilities
PPPL physicists have conducted simulations that suggest that applying magnetic fields to fusion plasmas can control instabilities known as Alfvén waves that can reduce the efficiency of fusion reactions.

Related Magnetic Fields Reading:

Magnetic Fields: Expanding American Abstraction, 1960s to Today
by Valerie Cassel Oliver (Author), Lowery Stokes Sims (Author), Erin Dziedzic (Editor), Melissa Messina (Editor)

In the history of American art, the contributions of African American artists to the development of abstraction have been largely overlooked.

Magnetic Fields aims to change this perspective by focusing on nonrepresentational work by women artists of color, presenting a more complete presentation of American abstraction than has previously been offered.

Intergenerational in scope, Magnetic Fields includes more than 20 artists born between 1891 and 1981, among them Lilian Thomas Burwell, Mildred Thompson, Candida Alvarez, Betty Blayton, Nanette... View Details


Power Tools for Health: How Pulsed Magnetic Fields (Pemfs) Help You
by Msc William Pawluk MD (Author), Caitlin Layne (Author)

Power tools revolutionized the building of your family home.
Now they will revolutionize your health.

Power Tools for Health will teach you to how to:
- treat new or chronic health conditions like pain, anxiety, insomnia, diabetes and injuries
- avoid annoying or potentially harmful side effects from pharmaceuticals or other treatments
- enhance and accelerate recovery from surgery

Research shows PEMFs accelerate the healing of almost any cell, tissue, organ, or condition.
Unlike much of modern medicine, which mostly focuses on symptom... View Details


NOW 2 kNOW Electro-Magnetic Fields
by Dr. T G D'Alberto (Author)

You're taking a challenging EM Fields course or simimlar while balancing umpteen other classes and maybe even a job. Your chief concern is to figure out, in the shortest time possible, how to successfully do the homework and exam problems. So, let’s get to it. The main stumbling blocks that trip up most students are conquered by a three-time teaching assistant to this course at Cornell. Get the help those students got! From a review of vector calculus to descriptions of the physics behind the math to detailed examples, this book is a must-have companion to any course addressing EM Fields.... View Details


Magnetic Fields: A Comprehensive Theoretical Treatise for Practical Use
by Heinz E. Knoepfel (Author)

A unique resource for physicists and engineers working with magnetic fields
An understanding of magnetic phenomena is essential for anyone working on the practical application of electromagnetic theory. Magnetic Fields: A Comprehensive Theoretical Treatise for Practical Use provides physicists and engineers with a thorough treatment of the magnetic aspects of classical electromagnetic theory, focusing on key issues and problems arising in the generation and application of magnetic fields. From magnetic potentials and diffusion phenomena to magnetohydrodynamics and properties of... View Details


Magnetic Field(s)
by Ron Loewinsohn (Author), Steve Erickson (Preface)

Organized around the idea that "you can't know what a magnetic field is like unless you're inside of it, " Ron Loewinsohn's first novel opens from the disturbing perspective of a burglar in the midst of a robbery and travels through the thoughts and experiences (both real and imaginary) of a group of characters whose lives are connected both coincidentally and intimately. All of the characters have a common desire to imagine and invent rather horrifying stories about the lives of people around them. As the novel develops, certain phrasings and images recur improbably, drawing the reader into... View Details


Magnetic Field of a Wire: The Method of Equivalent Sources
by Zafar Turakulov (Author)

Magnetostatics of thin wires is a specific branch of theoretical physics. Its main equation always contains a source, which can only be an endless curve in form. The field of an arc, which has endpoints, is not defined, therefore, there exists only entire field of an entire endless wire. This feature of the subject does not allow to employ the method of Green's functions, which requires that a wire is divided into small pieces. Therefore, only entire filed of an endless wire exists, therefore, such a wire plays the role of the "elementary" source. In this book an approach is outlined, which... View Details


Know Your Magnetic Field: Change Your Thinking, Change Your Life.
by William E. Gray (Author)

“We mortals operate on wave lengths from the Universal, the Trinity; these are our life waves. They are distributed, one wave from each of the ruling suns. Each of our waves is on a set length or frequency; the blending of the three waves is the Power. This sets the pattern of our individual frequency. It is the source of our personality, our identity and it is as distinct and individual as our own finger-prints. “On the strength of our wave we, similar to a planet, operate by our magnetic field through the medium and receive the knowledge we need from the vast pool of wisdom. It is... View Details


Reconnection of Magnetic Fields: Magnetohydrodynamics and Collisionless Theory and Observations
by J. Birn (Editor), E. R. Priest (Editor)

The reconnection of magnetic fields is one of the most fascinating processes in plasma physics, responsible for phenomena such as solar flares and magnetospheric substorms. The concept of reconnection has developed through recent advances in exploring the magnetospheres of the Sun and Earth through theory, computer simulations and spacecraft observations. The great challenge in understanding it stems from balancing the large volumes of plasma and magnetic fields involved with the energy release with the physical mechanism which relies on the strongly localized behavior of charged particles.... View Details


The Magnetic Fields
by André Breton (Author), Philippe Soupault (Author), David Gascoyne (Translator)

tr David Gascoyne View Details


Magnetic Fields' 69 Love Songs: A Field Guide (33 1/3)
by LD Beghtol (Author), Ken Emerson (Introduction)

A fully illustrated oral history of the Magnetic Fields' 1999 triple album, 69 Love Songs - an album that was afforded "classic" status by many almost as soon as it was released. LD Beghtol's book is chatty, incestuous, funny, dark, digressive, sexy, maddening, and delightful in equal measures. It documents a vital and influential scene from the inside, involving ukuleles and tears, citations and footnotes, analogue drum machines, and floods of cognac. Oh, and a crossword puzzle too.



The centre of the book is the secret history of these tuneful, acerbic, and sometimes... View Details

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

The Person You Become
Over the course of our lives, we shed parts of our old selves, embrace new ones, and redefine who we are. This hour, TED speakers explore ideas about the experiences that shape the person we become. Guests include aerobatics pilot and public speaker Janine Shepherd, writers Roxane Gay and Taiye Selasi, activist Jackson Bird, and fashion executive Kaustav Dey.
Now Playing: Science for the People

#478 She Has Her Mother's Laugh
What does heredity really mean? Carl Zimmer would argue it's more than your genes along. In "She Has Her Mother’s Laugh: The Power, Perversions, and Potential of Heredity", Zimmer covers the history of genetics and what kinship and heredity really mean when we're discovering how to alter our own DNA, and, potentially, the DNA of our children.