Powerful quantum computers insensitive to environmental interference. It may be the result of scientists after 40 years found evidence of quantum spin liquid in a magnetic material.
Frustrated magnetic materials does not sound like something to strive for. In fact, they may be the key to future powerful quantum computers, insensitive to interference from the environment.
For the most frustrated of the materials inside can be a desirable condition hide; so-called quantum spin liquid (see box). It is here that the building blocks for interference-resistant quantum computers can be. Called majoranapartiklar, alternatively majoranafemioner, they behave not like some of the ordinary particles that make up the materials in our environment.
Roughly, they consist of a half-electron, created by electrons split into two parts.
During the 40 years, physicists around the world chasing experimental proof of their existence. Now, reports an international team led by Arnad Banerjee at Oak Ridge National Laboratory in the United States that they have found proof that the phenomenon exists in the crystalline material is ruthenium.
The research results have been published in the scientific journal Nature Materials. In the English-language media described the incident as a major breakthrough materials.
– It is the most promising experiment in the area and it is performed by talented and renowned scientists. But the results still have to be repeated by other groups before the discovery can be confirmed, says Patrik Henelius, professor of theoretical physics at the Royal Institute of Technology and an expert on other variants of frustrated magnetic materials.
Why is a discovery of quantum spin liquid so important?
– Among other things, kvasipartiklarna in a quantum spin liquid (majoranapartiklarna) have properties that make them can probably be used to construct a quantum computer which is not affected by the environment. That distinguishes them from the quantum bits, called q-bits, used to date.
Thus opens the particles also the door to future failsafe and powerful quantum computers, created to simultaneously calculate all possible solutions to some problems.
But there is not today computers that qualify as quantum computers?
– it depends on how you define a quantum computer. If you mean it to be capable of factoring large numbers, which is the key for encryption, as they have so far only managed to factorize three-digit numbers. It is not so useful.
Those who seem to have made the most progress are the Canadian company D-Wave selling a version of the quantum computer. But the scientific community disagree on whether the computer really using quantum effects, and if it leads to that it can solve problems faster than classical computers.
– The company has won some debates, but it is still not a quantum computer in the sense that they could smash Google encryption.
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Doubtful electrons behind frustrated magnetism
the spin is a quantum mechanical property of elementary particles. It may have two directions – up or down. The spin of electrons is also the basis of magnetism, each of the spinning electrons forms a small permanent magnet.
In ferromagnetic materials such as iron, seeks electrons after being set up so that the spin all the time the same direction.
in antiferromagnetic materials would spin axes instead set up so that every two points up and every down.
Frustrated magnetic materials occurs when the electron’s spin can not meet any of the schemes fully out. The situation arises, inter alia, for the antiferromagnetic magnets in triangular structures. If the electron in a corner pointing up and the electron in the other down, it will be tricky for the electron in the third corner to know how the spin should be directed. It is the frustration that gives rise to quasiparticles in the magnets.
If the electrons never organize themselves, no matter how low the temperature gets, and quantum mechanical effects are important talk of quantum fluid.
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