In any computer’s hard drive, magnetic fields spin electrons this way or that. Now physicists have demonstrated that an electric field can do the same when applied to electrons in semiconductors. And unlike the older magnetic approach, their new device, called a spin gate, is capable of easily imparting a range of spin values. The team’s results, described in a report appearing today in the journal Nature, may one day help to scientists realize the ideal of spintronics—quantum computing based on electron spin states rather than charge.
David Awschalom of the University of Californa at Santa Barbara and colleagues trapped electrons in a seminconductor device made of layered gallium arsenide and aluminum gallium arsenide. By carefully adjusting the distribution of electron-transmitting aluminum across the device, they were able to create an energy barrier with sloping sides like a valley, instead of the usual box shape. When the researchers applied a voltage to the setup, the valley walls tilted like a seesaw. As electrons crossed from one material to the other through the well, quantum mechanical effects altered their spins according to how positive or negative the field was. "It’s a scalable, controllable way to manipulate the electron’s spin at the nanometer scale," Awschalom says. "Most schemes for quantum information processing require you to electrically tune the spin of the electron."
He adds that the very difficult next step would be to find a way to bind together the spin states of multiple electrons within these wells. But meeting this goal will require a lot of new physics, he says. "These devices will be a lab in which we can explore this physics."
JR Minkel | Scientific American
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24.11.2017 | Penn State
New proton record: Researchers measure magnetic moment with greatest possible precision
24.11.2017 | Johannes Gutenberg-Universität Mainz
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The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
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The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
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Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
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