Topological superconductor phase may solve decoherence problem in quantum computers

March 9, 2018 by Bob Yirka, report
Credit: CC0 Public Domain

A team of researchers from Japan, the U.S. and China, has identified a topological superconducting phase for possible use in an iron-based material in quantum computers. In their paper published in the journal Science, the team outlines their study of the phase, which, they claim, shows promise as a means for solving the decoherence problem in quantum computers.

As research surrounding quantum computers continues confront a number of problems. One is the tendency of quantum states to degrade, resulting in computing errors—a problem known as decoherence. Experts suggest that the solution to the problem is to develop a material capable of protecting the quantum state by employing just the right topological properties. In this way, localized noise would not be able to disturb the quantum state. In this new effort, the researchers report on the identification of a topological superconducting phase that they believe could satisfy this requirement.

The researchers report that they were able to attain three key kinds of measurements believed to be necessary for analyzing the of Fe(Te, Se) in sufficient detail, which they claim shows that the phase could prove suitable for protecting the in a system. They further report that the phase, once integrated into a suitable material, would be capable of supporting Majorana bound states (MBSs), which are quasiparticles so-named due to their discovery by Ettore Majorana. Prior research has suggested that a material capable of using Majorana properties might play a role in solving the decoherence problem.

The researchers note also that they were able to identify the helical spin polarization of the surface state and to measure the superconducting gap. They were also able to identify the . Taken together, the results of their testing indicate that MBSs could be induced in a material by exerting a magnetic field to the Fe(Te, Se). If their predictions pan out, the new phase could wind up as part of the next generation of quantum computers, possibly paving the way for machines capable of manipulating more qubits than those currently in use.

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

More information: Peng Zhang et al. Observation of topological superconductivity on the surface of an iron-based superconductor, Science (2018). DOI: 10.1126/science.aan4596 , … 3/07/science.aan4596

Topological superconductors are predicted to host exotic Majorana states that obey non-Abelian statistics and can be used to implement a topological quantum computer. Most of the proposed topological superconductors are realized in difficult-to-fabricate heterostructures at very low temperatures. Here by using high-resolution spin-resolved and angle-resolved photoelectron spectroscopy, we find that the iron-based superconductor FeTe1-xSex (x = 0.45, superconducting transition temperature Tc = 14.5 K) hosts Dirac-cone type spin-helical surface states at Fermi level; the surface states exhibit an s-wave superconducting gap below Tc. Our study shows that the surface states of FeTe0.55Se0.45 are 2D topologically superconducting, providing a simple and possibly high temperature platform for realizing Majorana states.

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3.7 / 5 (3) Mar 11, 2018
Increasing disturbing trend at and other web sites - tacking on a picture, any picture, that has nothing to do with the subject at hand. See Same stupid picture having nothing to do with the article.
1 / 5 (1) Mar 11, 2018
Same stupid picture having nothing to do with the article

For example: The magnetic order and Dirac cones in the pnictides. Spins are projected on a real-space lattice where the magnetic ordering wave vector (π,0) is shown (bottom plane). This wave vector connects two pieces of the Fermi surface on the reciprocal space (upper plane). The crystal symmetry, multiorbital nature along with the magnetic order in pnictides leaves behind linear band crossings in the shape of Dirac cones in some parts of the reciprocal space plane (upper plane). These Dirac cones highlight the mechanism of magnetic order.

2.3 / 5 (3) Mar 11, 2018
And the kook weighs in again.
2.3 / 5 (3) Mar 11, 2018
Same stupid picture having nothing to do with the article.

Quite a few stories have used this photo. It's a free stock photo from Pixabay. The only thing worse than these irrelevant photos are the irrelevant posts by kooks. A commenter quotes you then proceeds to go on what appears to be a Thorazine infused rant about Dirac cones, totally unrelated to your comment. Too many schizos in this unmoderated comment forum.
3 / 5 (2) Mar 11, 2018
@jd_ If you are registered at and are logged in then you can select "Ignore User" under a post and never see anything from mackita and the other schizo kook fools that love to shit their ignorance all over physics comment sections. I wouldn't bother looking at the comments without that facility. Over time you will find that there are only a handful of real contributors but they make it worthwhile.
not rated yet Mar 11, 2018
Ironically it's only my comment, which is perfectly on topic in this very thread. But most of posters here aren't even able to judge it as they only expect they will understand another posts (which they would value after then) - not the article itself. Apparently our definitions of OT kooks would differ. But I'm not here to discuss social aspects of this forum and to play a social game of its visitors.
not rated yet Mar 12, 2018
The decoherence means, that quantum computers are fast but also very noisy, so that for achieving the same reliability/precision like the classical computers we have to repeat the quantum algorithm multiple times until we will wipe out the advantage of speed... This is just the consequence of trivial fact, that the computational power of both quantum, both classical computers remains limited by the same uncertainty principle.
not rated yet Mar 12, 2018
The problem with decoherence of quantum computers is analogous to problems of classical computers with ohmic losses. In both cases the decreasing the resistance, i.e. superconductivity helps. The above study proposes to combine the topological superconductivity established at the surface of thin layer of semiconductors with high temperature superconductivity of pnictides and it predicts, that the thin layer superconductor would work even better. It can be understood easily, because the non-classical superconductivity arises if we constrain motion of electrons along as narrow path as possible and thin layer of superconductor (where the electrons are already moving along planes - hole stripes) would constrain their motion even more than within bulk superconductor.

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