Recent research offers a new spin on using nanoscale semiconductor structures to build faster computers and electronics. Literally.
University of Pittsburgh and Delft University of Technology researchers reveal in the Feb. 17 online issue of Nature Nanotechnology a new method that better preserves the units necessary to power lightning-fast electronics, known as qubits (pronounced CUE-bits). Hole spins, rather than electron spins, can keep quantum bits in the same physical state up to 10 times longer than before, the report finds.
"Previously, our group and others have used electron spins, but the problem was that they interacted with spins of nuclei, and therefore it was difficult to preserve the alignment and control of electron spins," said Sergey Frolov, assistant professor in the Department of Physics and Astronomy within Pitt's Kenneth P. Dietrich School of Arts and Sciences, who did the work as a postdoctoral fellow at Delft University of Technology in the Netherlands.
Whereas normal computing bits hold mathematical values of zero or one, quantum bits live in a hazy superposition of both states. It is this quality, said Frolov, which allows them to perform multiple calculations at once, offering exponential speed over classical computers. However, maintaining the qubit's state long enough to perform computation remains a long-standing challenge for physicists.
"To create a viable quantum computer, the demonstration of long-lived quantum bits, or qubits, is necessary," said Frolov. "With our work, we have gotten one step closer."
The holes within hole spins, Frolov explained, are literally empty spaces left when electrons are taken out. Using extremely thin filaments called InSb (indium antimonide) nanowires, the researchers created a transistor-like device that could transform the electrons into holes. They then precisely placed one hole in a nanoscale box called "a quantum dot" and controlled the spin of that hole using electric fields. This approach— featuring nanoscale size and a higher density of devices on an electronic chip—is far more advantageous than magnetic control, which has been typically employed until now, said Frolov.
"Our research shows that holes, or empty spaces, can make better spin qubits than electrons for future quantum computers."
"Spins are the smallest magnets in our universe. Our vision for a quantum computer is to connect thousands of spins, and now we know how to control a single spin," said Frolov. "In the future, we'd like to scale up this concept to include multiple qubits."
Coauthors of the paper include Leo Kouwenhoven, Stevan Nadj-Perge, Vlad Pribiag, Johan van den Berg, and Ilse van Weperen of Delft University of Technology; and Sebastien Plissard and Erik Bakkers from Eindhoven University of Technology in the Netherlands.
The paper, "Electrical control over single hole spins in nanowire quantum dots," appeared online Feb. 17 in Nature Nanotechnology. The research was supported by the Dutch Organization for Fundamental Research on Matter, the Netherlands Organization for Scientific Research, and the European Research Council.
Frolov and his Netherlands colleagues were recent winners of the 2012 Newcomb Cleveland Prize, an annual honor awarded to the author/s of the best research article/report appearing in Science, which is published weekly by the American Association for the Advancement of Science (AAAS). Read more about the award here: http://news.aaas.org/2012_annual_meeting/0215research-probing-a-quantum-phase-transition-wins-the-2011-aaas-newcomb-cleveland-prize-supported-by-affymetrix.shtml
B. Rose Huber | Source: EurekAlert!
Further information: www.pitt.edu
More articles from Physics and Astronomy:
Three-dimensional view helps laser in building new molecules
06.12.2013 | Max-Planck-Institut für Quantenoptik
NASA Goddard Planetary Instruments Score a Hat Trick
06.12.2013 | NASA/Goddard Space Flight Center
International team of scientists develops new feedback method for optimizing the laser pulse shapes used in the control of chemical reactions
In many ways, traditional chemical synthesis is similar to cooking. To alter the final product, you can change the ingredients or their ratio, change the method of mixing ingredients, or change the temperature or pressure of the environment of the ingredients.
Like an accomplished chef, chemists have become very skilled ...
A genetic defect protects mice from infection with influenza viruses
A new study published in the scientific journal PLOS Pathogens points out that mice lacking a protein called Tmprss2 are no longer affected by certain flu viruses.
The discovery was made by researchers from the Helmholtz Centre for Infection Research (HZI) in Braunschweig in collaboration with colleagues from Göttingen and ...
The Light: Global study gets underway with online user survey
Light has a fundamental impact on our sense of well-being and performance. In cooperation with Zumtobel, a supplier of lighting solutions, Fraunhofer IAO has launched a global user survey of lighting quality in offices. The objective is to identify the best lighting conditions for a variety of spaces and lighting ...
Quantum entanglement, a perplexing phenomenon of quantum mechanics that Albert Einstein once referred to as “spooky action at a distance,” could be even spookier than Einstein perceived.
Physicists at the University of Washington and Stony Brook University in New York believe the phenomenon might be intrinsically linked with wormholes, hypothetical features of space-time that in popular science fiction can provide a much-faster-than-light shortcut from one part of the universe to another.
But here’s the catch: One couldn’t actually ...
A star is formed when a large cloud of gas and dust condenses and eventually becomes so dense that it collapses into a ball of gas, where the pressure heats the matter, creating a glowing gas ball – a star is born.
New research from the Niels Bohr Institute, among others, shows that a young, newly formed star in the Milky Way had such an explosive growth, that it was initially about 100 times brighter than it is now. The results are published in the scientific journal, Astrophysical Journal Letters.
The young ...
06.12.2013 | Materials Sciences
06.12.2013 | Life Sciences
06.12.2013 | Life Sciences
05.12.2013 | Event News
04.12.2013 | Event News
12.11.2013 | Event News