early 20 th century, two famous discoveries about the spin made. One of them, discovered by Albert Einstein and Wander Johannes de Haas, explains a relationship between the spin of elementary particles. They found a relationship between magnetism and angular momentum. (At that time, Einstein also made his theory of general relativity .) A little more than a decade later, Paul Dirac gave its wave equation is the relativistic quantum mechanics , providing an explanation of electrons as elementary particles of spin 1 / 2.
Although these two discoveries have been around for nearly a century, Maekawa Sadamichi says that no one thought of the combination. "For almost 100 years, people did not consider putting these findings together. We decided to combine different ideas to reach a fundamental Hamiltonian and investigate the mechanical rotation in equation Dirac. "
Maekawa, is a scientist working with the Japan Atomic Energy Agency, as well as in the Japan Science and Technology has worked with scientists associated with Kyoto University and Tohoku University to get a new model spin that could be useful in the development of spintronics . Mamoru Matsuo, Jun'ichi Ieda and Eiji Saitoh also participated in the creation of the new model, which is published in Physical Review Letters under the title "Effects of mechanical rotation in the flow of spin."
"The Einstein effect - de Haas is caused by the conservation of angular momentum between magnetism and rotation, "said Maekawa. "Quantum mechanics tells us that the origin of magnetism is the spin of the electron. Recent advances in nanotechnology allow us to manipulate the flow of electron spin, or spin current." He points out that the relationship between spin current and magnets studied for applications in nanodevices, but has paid little attention to the way the rotation could be used to control the flow of spin.
schematic representation of the path of the electrons (red and blue areas) under mechanical rotation (curved gray arrow) and in the presence of a magnetic field ( Green arrow up). Crédito.Sadamichi Maekawa.
In Japan, Maekawa and his colleagues decided that the study of how to use the mechanical rotation direct the flow of spin could be advantageous in the development of spintronics devices that scientists believe could one day replace the silicon-based electronics. "We found we had to add to the equation of general relativity," Maekawa said. "Dirac included special relativity , but general relativity is also needed. We have combined the two theories of Einstein, and added them to the theory of quantum mechanics. In this way, we've added rotational quantum mechanical equation. "
Part of this new model includes the extension of the physical system in a non-inertial frame from its current inertial frame . Maekawa and his colleagues were based on the fact that the dynamics of the spin current is closely related to the spin-orbit interaction as a result of the use of low energy limit of the equation Dirac. "We try to combine general relativity and the spin current, although general relativity is not as popular in condensed matter physics right now, "he says. The result, Maekawa said, is that it should be possible to control the spin current by mechanical means.
For now, the model is theory." We have formulated an equation, and in the future hope to test the theory, "Maekawa said. He believes that" this theory will give rise to nanoscale motors and dynamos, "provide a practical method in the future spintronics.
read study HERE
source of information:
http://www.physorg.com/news/2011-03-combination-relativity-quantum-mechanics-spintronics.html
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