 |
|
'Science:' Novel quantum effect directly observed and explained
February 13, 2009An international research team has succeeded in gaining an in-depth insight into an unusual phenomenon, as reported in the current edition of the high-impact journal "Science". The researchers succeeded for the first time in directly measuring the spin of electrons in a material that exhibits the quantum spin Hall effect, which was theoretically predicted in 2004 and first observed in 2007. Astonishingly, the spin currents flow without any external stimulus as a result of the internal structure of the material. The flow of information is loss-free, even for slight irregularities. This paves the way towards fault-tolerant quantum computers and towards a source of spin currents.
The spin is a quantum-mechanical property of elementary particles and as a rule it occurs in two variations. This is what makes it suitable for use as a binary information carrier. In hard disk drives, for example, spins are already being used to store digital information.
In 2007, physicists from Germany and the USA observed a new phenomenon that could make it possible to transport and electrically manipulate information in future storage media almost loss-free - the quantum spin Hall effect. The discovery was hailed by the high-impact journal "Science" as one of the ten most important scientific breakthroughs of 2007.
The first study that succeeded in directly observing the spin of flowing particles was published this week in "Science" by an international research team, which included Dr. Gustav Bihlmayer from Forschungszentrum Jülich, member of the Helmholtz Association. Until now, the quantum spin Hall effect could only be indirectly proven.
"We were able to show for the first time that two spin currents flow in opposite directions in the edge region of an alloy of bismuth and antimony. An external energy supply is not required; losses cannot occur," explained Dr. Gustav Bihlmayer from the Jülich Institute of Solid State Research. The causes of this astonishing phenomenon are interactions within the material. Of particular interest to materials scientists is the fact that imperfections in the material do not impair the spin currents. "This means that materials known as topological materials have spin currents that can be manipulated electrically and are therefore suitable for use as spin sources. They could even pave the way towards fault-tolerant quantum computers," said Bihlmayer. "Our process will make it possible to test the suitability of materials for this purpose in the future."
The current study makes use of theoretical calculations and photoelectron spectroscopy. The photons in a synchrotron beam cause electrons to be emitted from the material surface. The energy and momentum distribution, as well as the spin of the particles, can be used to derive concrete information on the occurrence of the quantum spin Hall effect. Previous methods were based on measurements of the conductivity in the materials at variable voltages.
Spins for data processing
Spins are a hot topic in research. Physicists and nanoelectricians have high hopes for what is known as spin electronics. Spin electronics does not just exploit the electric charge of electrons and nuclei but also their spin, and should therefore lead to the development of new approaches for the processing and coding of information in information processing. Faster, smaller and more energy-efficient computers could thus become a reality, as could completely new components capable of performing a number of different functions such as storage, logic and communication. One of the most prominent ideas is that of the quantum computer. For spin-electronic concepts, scientists conducting basic research are desperately searching for new materials and phenomena that will make it possible to control both spin orientation and spin flow.
Helmholtz Association of German Research Centres
The first study that succeeded in directly observing the spin of flowing particles was published this week in "Science" by an international research team, which included Dr. Gustav Bihlmayer from Forschungszentrum Jülich, member of the Helmholtz Association. Until now, the quantum spin Hall effect could only be indirectly proven.
"We were able to show for the first time that two spin currents flow in opposite directions in the edge region of an alloy of bismuth and antimony. An external energy supply is not required; losses cannot occur," explained Dr. Gustav Bihlmayer from the Jülich Institute of Solid State Research. The causes of this astonishing phenomenon are interactions within the material. Of particular interest to materials scientists is the fact that imperfections in the material do not impair the spin currents. "This means that materials known as topological materials have spin currents that can be manipulated electrically and are therefore suitable for use as spin sources. They could even pave the way towards fault-tolerant quantum computers," said Bihlmayer. "Our process will make it possible to test the suitability of materials for this purpose in the future."
The current study makes use of theoretical calculations and photoelectron spectroscopy. The photons in a synchrotron beam cause electrons to be emitted from the material surface. The energy and momentum distribution, as well as the spin of the particles, can be used to derive concrete information on the occurrence of the quantum spin Hall effect. Previous methods were based on measurements of the conductivity in the materials at variable voltages.
Spins for data processing
Spins are a hot topic in research. Physicists and nanoelectricians have high hopes for what is known as spin electronics. Spin electronics does not just exploit the electric charge of electrons and nuclei but also their spin, and should therefore lead to the development of new approaches for the processing and coding of information in information processing. Faster, smaller and more energy-efficient computers could thus become a reality, as could completely new components capable of performing a number of different functions such as storage, logic and communication. One of the most prominent ideas is that of the quantum computer. For spin-electronic concepts, scientists conducting basic research are desperately searching for new materials and phenomena that will make it possible to control both spin orientation and spin flow.
Helmholtz Association of German Research Centres
Quantum Spin Current Events and Quantum Spin News RSSNew Exotic Material Could Revolutionize Electronics
Move over, silicon-it may be time to give the Valley a new name. Physicists at the Department of Energy's (DOE) SLAC National Accelerator Laboratory and Stanford University have confirmed the existence of a type of material that could one day provide dramatically faster, more efficient computer chips.
Quantum dance: Discovery led by Princeton researchers could revolutionize computing
An international team of scientists, led by a Princeton University group, has observed an exciting and strange behavior in electrons' spin within a new material that could be harnessed to transform computing and electronics.
Physicists team up to learn how quantum mechanical states break down
Researchers at the US Department of Energy's Ames Laboratory, the University of California, Santa Barbara, and Microsoft Station Q have made significant advancements in understanding a fundamental problem of quantum mechanics -- one that is blocking efforts to develop practical quantum computers with processing speeds far superior to conventional computers. Their respective theoretical and experimental studies investigate how microscopic objects lose their quantum-mechanical properties through interactions with the environment.
SU Professor Works With International Researchers to Make Quantum Physics Discovery
John F. DiTusa, professor of physics and astronomy at LSU, and his international colleagues have discovered an unusual magnetic material that behaves very differently from the average refrigerator magnet.
Hidden order found in a quantum spin liquid
An international team, including scientists from the London Center for Nanotechnology, has detected a hidden magnetic "quantum order" that extends over chains of 100 atoms in a ceramic without classical magnetism. The findings, which are published today, July 26, by Science, have implications for the design of devices and materials for quantum information processing.
Discovery of 'hidden' quantum order improves prospects for quantum super computers
An international team of scientists, including several at The Johns Hopkins University, has detected a hidden magnetic "quantum order" that extends over chains of nearly 100 atoms in a material that is otherwise magnetically disordered.
New Materials for Making "Spintronic" Devices
An interdisciplinary group of scientists at the U.S. Department of Energy's Brookhaven National Laboratory has devised methods to make a new class of electronic devices based on a property of electrons known as "spin," rather than merely their electric charge.
More Quantum Spin Current Events and Quantum Spin News Articles
 |
The Story of Spin by Sin-itiro Tomonaga (Author), Takeshi Oka (Translator) All atomic particles have a particular "spin," analogous to the earth's rotation on its axis. The quantum mechanical reality underlying spin is complex and still poorly understood. Sin-itiro Tomonaga's The Story of Spin remains the most complete and accessible treatment of spin, and is now available in English translation. Tomonaga tells the tale of the pioneers of physics and their difficult journey toward an understanding of the nature of spin and its relationship to statistics. His clear unfolding of the tale of spin is invaluable to students of physics, chemistry, and astronomy, and his description of the historical development of spin will interest historians and philosophers of science. "This piece of the history of physics will provide excellent and exciting reading. . . .... |
 |
Quantum Snapshot® LS Spin Reel, SLS20 by QUANTUM Quantum Snapshot LS Spin Reel with spare spool. This Quantum Snapshot LS Spin Reel comes with a spare graphite spool to give you the flexibility to change line weights to match your fishing conditions. And there are even more reasons to buy: Exclusive Snapshot II trigger system; 6 ball-bearing drive system; Aluminum Long Stroke MaxCast spool; Front-adjustable drag; Spare graphite spool. State Model. Order Today! Model: SLS10, Bearings: 6, Gear Ratio: 5.3:1, Line Capacity: 125 yds. / 4 lb., Weight: 8.2 ozs. Model: SLS20, Bearings: 6, Gear Ratio: 5.3:1, Line Capacity: 160 yds. / 6 lb., Weight: 9.8 ozs. Model: SLS30, Bearings: 6, Gear Ratio: 5.3:1, Line Capacity: 160 yds. / 8 lb., Weight: 11.5 ozs. Quantum Snapshot LS Spin Reel |
 |
Quantum Leap Roeth And Grey (Primary Contributor) |
 |
Process Tomography of a nuclear quadrupolar spin quantum processor: Characterization of quantum algorithms and non-Markovian decoherence by Hermann Kampermann (Author) NMR quantum computing with qubit systems represented by nuclear spins with I=1/2 of small moleculesin liquids has led to the most successful experimental quantum information processors so far. We use the quadrupolar spin-3/2 sodium nuclei of a NaNO3 single crystal as a virtual two-qubit system. The large quadrupolar coupling in comparison with the environmental interactions and the usage ofstrongly modulating pulses allow us to manipulate the system fast enough and at the same timekeeping the decoherence reasonably slow. The experimental challenge is to characterize thecalculation behavior of the quantum processor by process tomography which is here adapted tothe quadrupolar spin system. The results of a selection of quantum gates and algorithms arepresented as well as a detailed analysis... |
|
Quantum Leap Field Trips with Pug and Zero: Spin Cycle Also With: MediaPro (Producer) In this episode of the Emmy Award-winning children's educational program, the "Exploragyzer" quantum field traveling machine lands Pug and Zero in a state-of-the-art recording studio, where they find out what's involved in capturing a live song performance on a mechanical or digital device that can be played back and enjoyed indefinitely. The curriculum areas covered include science and history. Produced by the acclaimed educational firm MediaPro, Quantum Leap Field Trips wraps its carefully researched lessons in a fun adventure package. Filmed on location, the series chronicles fictional quantum travels to real places by the character Charlotte "Charly" Wells, a teen inventor searching for Pug and Zero, her life-sized, Muppet-like pals from another dimension. Pug and Zero never know when... | |
|
The Quantum Theory of Spin/quantum Mechanical Postulates for Bound Systems/the Postulates of Elementary Quantum Mechanics by Open University Press (Publisher) | |
|
Quantum spin transport in mesoscopic interferometer.: An article from: Progress in Physics by Walid A. Zein (Author), Adel H. Phillips (Author), Omar A. Omar (Author) This digital document is an article from Progress in Physics, published by Thomson Gale on October 1, 2007. The length of the article is 1890 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available in your Amazon.com Digital Locker immediately after purchase. You can view it with any web browser. Citation Details Title: Quantum spin transport in mesoscopic interferometer. Author: Walid A. Zein Publication: Progress in Physics (Magazine/Journal) Date: October 1, 2007 Publisher: Thomson Gale Volume: 2007 Issue: 4 Page: 18(4) Distributed by Thomson... | |
|
Crossover-Time in Quantum Boson and Spin Systems (Lecture Notes in Physics New Series M) by Gennady P. Berman (Author), Evgeny N. Bulgakov (Author), Darryl D. Holm (Author) The authors compare classical and quantum dynamics in the quasiclassical region of parameters and under the condition of unstable (chaotic) classical behavior. They estimate the characteristic time-scale at which classical and quantum solutions start to differ significantly. The method is based on exact equations for time-dependent expectation values in boson and spin coherent states, and applies to rather general Hamiltonians with many degrees of freedom. The authors develop a consistent dynamical theory for quantum nonintegrable Hamiltonians and provide explicit examples of classical-quantum "crossover-time", a very common and fundamental phenomenon in quantum nonintegrable systems. This book can be recommended to graduate students and to specialists. | |
 |
Quantum Optixâ„¢ Spin Reel, 10 by QUANTUM Quantum Optix Spin Reel with spare spool. This Quantum Optix Spin Reel comes with a spare graphite spool to give you the flexibility to change line weights to match your fishing conditions. And there are even more reasons to buy: Aluminum Long Stroke spool; 4 stainless steel bearings; Continuous Anti-Reverse; Smooth front-adjustable drag; Spare graphite spool. State Model. Order Now! Model: OP10F, Bearings: 4, Gear Ratio: 5.3:1, Line Capacity: 125 yds. / 4 lb., Weight: 7.7 ozs. Model: OP20F, Bearings: 4, Gear Ratio: 5.3:1, Line Capacity: 160 yds. / 6 lb., Weight: 9 ozs. Model: OP30F, Bearings: 4, Gear Ratio: 5.3:1, Line Capacity: 160 yds. / 8 lb., Weight: 11.2 ozs. Model: OP40F, Bearings: 4, Gear Ratio: 5.3:1, Line Capacity: 230 yds. / 10 lb., Weight: 11.6 ozs. Quantum Optix Spin Reel |
 |
Spins in Optically Active Quantum Dots: Concepts and Methods by Oliver Gywat (Author), Hubert J. Krenner (Author), Jesse Berezovsky (Author) Filling a gap in the literature, this up-to-date introduction to the field provides an overview of current experimental techniques, basic theoretical concepts, and sample fabrication methods. Following an introduction, this monograph deals with optically active quantum dots and their integration into electro-optical devices, before looking at the theory of quantum confined states and quantum dots interacting with the radiation field. Final chapters cover spin-spin interaction in quantum dots as well as spin and charge states, showing how to use single spins for break-through quantum computation. A conclusion and outlook round off the volume. The result is a primer providing the essential basic knowledge necessary for young researchers entering the field, as well as... |
| © 2009 BrightSurf.com |