Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Unconventional superconductor may be used to create quantum computers of the future

19.02.2018

They have probably succeeded in creating a topological superconductor

With their insensitivity to decoherence what are known as Majorana particles could become stable building blocks of a quantum computer. The problem is that they only occur under very special circumstances. Now researchers at Chalmers University of Technology have succeeded in manufacturing a component that is able to host the sought-after particles.


After an intensive period of analyses the research team led by Professor Floriana Lombardi, Chalmers University of Technology, was able to establish that they had probably succeeded in creating a topological superconductor.

Credit: Johan Bodell/Chalmers University of Technology

Researchers throughout the world are struggling to build a quantum computer. One of the great challenges is to overcome the sensitivity of quantum systems to decoherence, collaps of superpositions. One track within quantum computer research is therefore to make use of what are known as Majorana particles, which are also called Majorana fermions. Microsoft is also committed to the development of this type of quantum computer.

Majorana fermions are highly original particles, quite unlike those that make up the materials around us. In highly simplified terms, they can be seen as half electron. In a quantum computer the idea is to encode information in a pair of Majorana fermions which are separated in the material, which should, in principle, make the calculations immune to decoherence.

So where do you find Majorana fermions?

In solid state materials they only appear to occur in what are known as topological superconductors - a new type of superconductor that is so new and special that it is hardly ever found in practice. But a research team at Chalmers University of Technology is now among the first in the world to submit results indicating that they have actually succeeded in manufacturing a topological superconductor.

"Our experimental results are consistent with topological superconductivity," says Floriana Lombardi, Professor at the Quantum Device Physics Laboratory at Chalmers.

To create their unconventional superconductor they started with what is called a topological insulator made of bismuth telluride, Be2Te3. A topological insulator is mainly just an insulator - in other words it does not conduct current - but it conducts current in a very special way on the surface. The researchers have placed a layer of a conventional superconductor on top, in this case aluminium, which conducts current entirely without resistance at really low temperatures.

"The superconducting pair of electrons then leak into the topological insulator which also becomes superconducting," explains Thilo Bauch, Associate Professor in Quantum Device Physics.

However, the initial measurements all indicated that they only had standard superconductivity induced in the Bi2Te3 topological insulator. But when they cooled the component down again later, to routinely repeat some measurements, the situation suddenly changed - the characteristics of the superconducting pairs of electrons varied in different directions.

"And that isn't compatible at all with conventional superconductivity. Suddenly unexpected and exciting things occurred," says Lombardi.

Unlike other research teams, Lombardi's team used platinum to assemble the topological insulator with the aluminium. Repeated cooling cycles gave rise to stresses in the material (see image below), which caused the superconductivity to change its properties.

After an intensive period of analyses the research team was able to establish that they had probably succeeded in creating a topological superconductor.

"For practical applications the material is mainly of interest to those attempting to build a topological quantum computer. We ourselves want to explore the new physics that lies hidden in topological superconductors - this is a new chapter in physics," Lombardi says.

###

The results were recently published in the scientific journal Nature Communications: Induced unconventional superconductivity on the surface states of Bi2Te3 topological insulator

More about quantum computers and the Majorana particle

A large Quantum computer project in the Wallenberg Quantum Technology Centre is underway at Chalmers University of Technology. It is, however, based on technology other than topological superconductors.

https://www.chalmers.se/en/centres/wacqt/Pages/default.aspx

The Majorana particle was predicted by the Italian physicist Ettore Majorana in 1937. It is a highly original fundamental particle which - like electrons, neutrons and protons - belongs to the group of fermions. Unlike all other fermions the Majorana fermion is its own antiparticle.

Media Contact

Christian Borg
christian.borg@chalmers.se
46-317-723-395

 @chalmersuniv

http://www.chalmers.se/en/ 

Christian Borg | EurekAlert!

More articles from Physics and Astronomy:

nachricht What happens when we heat the atomic lattice of a magnet all of a sudden?
17.07.2018 | Forschungsverbund Berlin

nachricht Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Microscopic trampoline may help create networks of quantum computers

17.07.2018 | Information Technology

In borophene, boundaries are no barrier

17.07.2018 | Materials Sciences

The role of Sodium for the Enhancement of Solar Cells

17.07.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>