Nav: Home

Majorana runners go long range: New topological phases of matter unveiled

February 26, 2018

Researchers from Universidad Complutense de Madrid, MIT and Harvard University have discovered a mechanism that enhances the presence of Majorana particles at the edges of a topological superconductor, thanks to the presence of long-range magnetic interactions. Moreover, they have shown that it is possible to find new topological phases of matter by merging distant Majoranas into a new particle. This great achievement could have future applications for quantum technologies.

In a recent paper published in Physical Review Letters, these researchers explain how they improve the propagation of Majorana particles at the edge of a topological superconductor by exploring the nature of long-range interactions, and transforming the Majoranas into more stable quasiparticles.

The study of topological phases of matter has become a very active field of research, that is revolutionizing our understanding of nature. It has given rise to new materials like topological insulators, Weyl semimetals, and topological superconductors.

Topological superconductors are materials that, besides conducting electric current without dissipating energy as heat, they host unconventional particles known as Majorana fermions. It is unknown whether these particles exist in high energy physics, but remarkably, Majorana fermions appear as low energy excitations (quasiparticles) in certain materials.

Useful to build quantum computers

These particles are very exotic in condensed matter. They behave as their own antiparticle and have been proposed as building blocks of future topological quantum computers. A quantum computer uses certain remarkable properties of quantum physics to solve tasks and processes, that would otherwise be unsurmountable by conventional computers.

Nonetheless, these properties (such as quantum entanglement between tiny particles) are very sensitive to environmental interactions (decoherence). This is the main reason why the construction of quantum computers turns out to be a great challenge that is currently being tackled by research labs and companies all over the world. The Majorana fermions that appear in topological superconductors are much more robust than other conventional particles, which would allow to build such novel computers.

The existence of Majorana fermions had been already proven in earlier works: chains of magnetic impurities placed on top of a superconductor substrate have shown that long-range magnetic interactions between electrons appear very naturally in these materials.

According to the authors of this publication, these interactions are very similar to the one between two magnets that feel attraction or repulsion to one another. In this case, it would be the magnetic moments of the electrons that interact with each other instead of the magnets.

However, it remained unknown what the effect of these magnetic interactions was over the properties of superconducting materials. This is precisely what this research work has solved.

Merging of Majorana particles

The researchers of this collaboration have found cases where the long-range effects of the magnetic interactions were so strong, that two distant Majorana fermions merged into a non-local topological quasiparticle.

This surprising effect could be used to store quantum information in a non-degenerate system (i.e. two-level systems with different energy), but with extra protection against external noise, caused by decoherence, or the loss of quantum effects.

These findings represent a great leap towards the understanding of the role of long-range magnetic interactions in the realm of topological superconductors. Moreover, these results will spark generation of novel topological phases of mater, widening their current applications in spintronics, quantum memories and computers, and other related fields.
-end-
Reference

Chiral Topological Superconductors Enhanced by Long-Range Interactions, O. Viyuela, L. Fu, M. A. Martin-Delgado, Phys. Rev. Lett. 120, 017001 (2018)

QUITEMAD+

Related Energy Articles:

Quantum vacuum: Less than zero energy
According to quantum physics, energy can be 'borrowed' -- at least for some time.
New discipline proposed: Macro-energy systems -- the science of the energy transition
In a perspective published in Joule on Aug. 14, a group of researchers led by Stanford University propose a new academic discipline, 'macro-energy systems,' as the science of the energy transition.
How much energy storage costs must fall to reach renewable energy's full potential
The cost of energy storage will be critical in determining how much renewable energy can contribute to the decarbonization of electricity.
Energy from seawater
A new battery made from affordable and durable materials generates energy from places where salt and fresh waters mingle.
Shifts to renewable energy can drive up energy poverty, PSU study finds
Efforts to shift away from fossil fuels and replace oil and coal with renewable energy sources can help reduce carbon emissions but do so at the expense of increased inequality, according to a new Portland State University study
Putting that free energy around you to good use with minuscule energy harvesters
Scientists at Tokyo Tech developed a micro-electromechanical energy harvester that allows for more flexibility in design, which is crucial for future IoT applications.
A new way to transfer energy between cells
Researchers have described a new method for the transmission of electrons between proteins that refutes the evidence from experiments until now.
Renewable energy cooperatives, an opportunity for energy transition
Three researchers from the UPV/EHU's Faculty of Engineering -- Bilbao and the University of Valladolid have explored how renewable energy cooperatives have evolved.
MIT Energy Initiative study reports on the future of nuclear energy
In new MIT report, study authors analyze the reasons for the current global stall of nuclear energy capacity and discuss measures that could be taken to arrest and reverse that trend.
Wave energy converters are not geared towards the increase in energy over the last century
Wave energy converters are designed to generate the maximum energy possible in their location and take a typical year in the location as a reference.
More Energy News and Energy Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.