Subscribe to our free daily newsletters
. 24/7 Space News .




Subscribe to our free daily newsletters



TIME AND SPACE
Finding the highly sought Majorana quasiparticle
by Staff Writers
Santa Barbara CA (SPX) Nov 22, 2017


Deterministic growth of InSb nanowire networks

UC Santa Barbara scientists are on the cusp of a major advance in topological quantum computing.

In a paper that appears in the journal Nature, Chris Palmstrom, a UCSB professor of electrical and computer engineering and of materials, and colleagues describe a method by which "hashtag"- shaped nanowires may be coaxed to generate Majorana quasiparticles.

These quasiparticles are exotic states that if realized, can be used to encode information with very little risk of decoherence - one of quantum computing's biggest challenges - and thus, little need for quantum error correction.

"This was a really good step toward making things happen," said Palmstrom. In 2012, Dutch scientists Leo Kouwenhoven and Erik Bakkers (also authors on the paper) from the Delft and Eindhoven Universities of Technology in the Netherlands, reported the first observation of states consistent with these quasiparticles. At the time, however, they stopped short of definitive proof that they were in fact the Majoranas, and not other phenomena.

Under the aegis of Microsoft Corporation's Research Station Q headquartered on the UCSB campus, this team of scientists is part of a greater international effort to build the first topological quantum computer.

The quasiparticles are named for Italian physicist Ettore Majorana, who predicted their existence in 1937, around the birth of quantum mechanics. They have the unique distinction of being their own antiparticles - they can annihilate one another. They also have the quality of being non-Abelian, resulting in the ability to "remember" their relative positions over time - a property that makes them central to topological quantum computation.

"If you are to move these Majoranas physically around each other, they will remember if they were moved clockwise or anticlockwise," said Mihir Pendharkar, a graduate student researcher in the Palmstrom Group. This operation of moving one around the other, he continued, is what is referred to as "braiding."

Computations could in theory be performed by braiding the Majoranas and then fusing them, releasing a poof of energy - a "digital high" - or absorbing energy - a "digital low."

The information is contained and processed by the exchange of positions, and the outcome is split between the two or more Majoranas (not the quasiparticles themselves), a topological property that protects the information from the environmental perturbations (noise) that could affect the individual Majoranas.

However, before any braiding can be performed, these fragile and fleeting quasiparticles must first be generated. In this international collaboration, semiconductor wafers started their journey with patterning of gold droplets at the Delft University of Technology.

With the gold droplets acting as seeds, Indium antimonide (InSb) semiconductor nanowires were then grown at the Eindhoven University of Technology. Next, the nanowires traveled across the globe to Santa Barbara, where Palmstrom Group researchers carefully cleaned and partially covered them with a thin shell of superconducting aluminum. The nanowires were returned to the Netherlands for low temperature electrical measurements.

"The Majorana has been predicted to occur between a superconductor and a semiconductor wire," Palmstrom explained.

Some of the intersecting wires in the infinitesimal hashtag-shaped device are fused together, while others barely miss one another, leaving a very precise gap. This clever design, according to the researchers, allows for some regions of a nanowire to go without an aluminum shell coating, laying down ideal conditions for the measurement of Majoranas.

"What you should be seeing is a state at zero energy," Pendharkar said. This "zero-bias peak" is consistent with the mathematics that results in a particle being its own antiparticle and was first observed in 2012.

"In 2012, they showed a tiny zero-bias blip in a sea of background," Pendharkar said. With the new approach, he continued, "now the sea has gone missing," which not only clarifies the 2012 result and takes the researchers one step closer to definitive proof of Majorana states, but also lays a more robust groundwork for the production of these quasiparticles.

Majoranas, because of their particular immunity to error, can be used to construct an ideal qubit (unit of quantum information) for topological quantum computers, and, according to the researchers, can result in a more practicable quantum computer because its fault-tolerance will require fewer qubits for error correction.

"All quantum computers are going to be working at very low temperatures," Palmstrom said, "because 'quantum' is a very low energy difference." Thus, said the researchers, cooling fewer fault-tolerant qubits in a quantum circuit would be easier, and done in a smaller footprint, than cooling more error-prone qubits plus those required to protect from error.

The final step toward conclusive proof of Majoranas will be in the braiding, an experiment the researchers hope to conduct in the near future. To that end, the scientists continue to build on this foundation with designs that may enable and measure the outcome of braiding.

"We've had the funding and the expertise of people who are experts in the measurements side of things, and experts in the theory side of things," Pendharkar said, "and it has been a great collaboration that has brought us up to this level."

TIME AND SPACE
Electron backscatter diffraction yields microstructure insights
Washington DC (SPX) Nov 17, 2017
High-efficiency electric motors with tailored speed-torques, determined by their magnetic components, are essential for sustainable, successful electric automobile drive concepts. Soft magnetic core engineering plays a key role in these motors, where the main soft magnetic materials used today are electrical steels. But for higher-frequency applications, soft magnetic composites (SMCs) are also ... read more

Related Links
University of California - Santa Barbara
Understanding Time and Space


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

TIME AND SPACE
New motion sensors major step towards cheaper wearable technology

Can a magnetic sail slow down an interstellar probe

SSL Selected to Conduct Power and Propulsion Study for NASA's Deep Space Gateway Concept

MDA Selects AdaCore's GNAT Pro Assurance Development Platform for ISS Software

TIME AND SPACE
Aerojet Rocketdyne supports ULA Delta II launch of JPSS-1

Old Rivals India, China Nurture New Rivalry in Satellite Launch Business

NASA launches next-generation weather satellite

SpaceX postpones launch of secretive Zuma mission

TIME AND SPACE
Winds Blow Dust off the Solar Panels Improving Energy Levels

Recurring Martian Streaks: Flowing Sand, Not Water?

From Hannover around the world and to the Mars: LZH delivers laser for ExoMars 2020

NASA Selects Instrument for Future International Mission to Martian Moons

TIME AND SPACE
China plans for nuclear-powered interplanetary capacity by 2040

China plans first sea based launch by 2018

China's reusable spacecraft to be launched in 2020

Space will see Communist loyalty: Chinese astronaut

TIME AND SPACE
Space Launch plans UK industry tour

Astronaut meets volcano

European Space Week starts in Estonia

New Chinese sat comms company awaits approval

TIME AND SPACE
New way to write magnetic info could pave the way for hardware neural networks

Borophene shines alone as 2-D plasmonic material

Metal membranes in construction: From Russia with love

Spin current from heat: New material increases efficiency

TIME AND SPACE
Lava or Not, Exoplanet 55 Cancri e Likely to have Atmosphere

Images of strange solar system visitor peel away some of the mystery

Familiar-Looking Messenger from Another Solar System

Space dust may transport life between worlds, research suggests

TIME AND SPACE
Pluto's hydrocarbon haze keeps dwarf planet colder than expected

Jupiter's Stunning Southern Hemisphere

Watching Jupiter's multiple pulsating X-ray Aurora

Help Nickname New Horizons' Next Flyby Target




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement