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UdaraW
Spot on, Skyhigh. The width and height of the commercialization window depends ...
Skyhigh
Research improves silicon for quantum computing
Julien Happich, EE Times Europe
8/26/2010 6:47 AM EDT
LONDON – A team of scientists from University College London (UCL) and the National High Magnetic Field Lab (NHMFL) in Florida has discovered a more efficient way to encode quantum information in silicon. The research is described in the journal Nature Materials and in a forthcoming article in Physical Review Letters.
Despite being compatible with the silicon, bismuth has been overlooked to date in favor of phosphorus. This is probably because phosphorous is familiar as a dopant and conventional ICs exploit phosphorous dissolved in silicon.
However, the researchers in London and Florida have found that bismuth outperforms phosphorus at encoding quantum states. Bismuth is the heaviest stable atom and has a correspondingly large nuclear spin: its quantum spin is like a tiny compass needle that can exist in one of ten states corresponding to different tilts (see illustration) instead of the two directions available to a phosphorus nucleus. This allows bismuth nuclei to store much more quantum information than phosphorous nuclei, because the quantum state space is now ten- rather than two-dimensional.
Illustration: A bismuth atom in one slice of a silicon crystal. The large light green cloud shows the possible positions of the bound electron's wavefunction, and the purple arrow is its spin. The bismuth nuclear spin (blue arrow) can tilt in ten different directions, shown in red and yellow. Artwork by Manuel Vögtli (LCN)
The observations lead to the suggestion of a "dream team" using both bismuth and phosphorus atoms in silicon: as they are different, they can be manipulated independently. The bismuth would store quantum information while the phosphorus could provide access control and information flow.
"The experimental hurdles overcome include the use of bismuth in silicon for the preparation, control and storage of quantum information," explained lead author Gavin Morley of the London Centre for Nanotechnology (LCN) at UCL. He continued: "Bigger is better in this case because the larger nucleus of bismuth provides more room for storing quantum information."
Co-author Marshall Stoneham, also of the LCN, added "If a quantum computer could be built, it could solve some problems long regarded as impossible. Having one type of atom for storing quantum information in silicon, and another type for controlling it is like bringing a second person into a one-man conversation: much more interesting!"
Greg Boebinger, the Director of the NHMFL which hosted some of the experiments reported, commented: "This result is a big incentive to use silicon for research into quantum technologies."
Related links and articles:
Visit the University College London at www.ucl.ac.uk
Visit the National High Magnetic Field Laboratory (NHMFL) at www.magnet.fsu.edu
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iniewski
8/26/2010 5:15 PM EDT
Very interesting development but the proof is in details and real application space. We have seen so many failed attempts in quantum computing in the past. That should not prevent people from trying but one has to be a little skeptical. The road from research announcement to real technology can be veeeeeery long...Kris
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pixies
8/26/2010 5:48 PM EDT
I have never fully understand how the researchers plan to interface with a quantum computer? What the programing language is going to look like?
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Skyhigh
8/27/2010 3:00 PM EDT
To Pixies:
Programming language is totally independent of quantum material & storage device development.
Thus it doesn't matter at all.
To iniewski:
It depends which side of the coin you are looking at. When academic research aligns closely with the roadmap of industrial giants, there are funds to drive it from the labs to production lines. When it isn't, you got to wait until mainstream technology arrives at the verge of abyss. Then these giants will set their eyes upon it as the next big thing for another wave of revolution.
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UdaraW
8/29/2010 6:45 PM EDT
Spot on, Skyhigh. The width and height of the commercialization window depends more on the state of the industry than on the merit of the research outcome itself.
A marginal invention can achieve a great deal of commercial value and publicity if the industry leaders have been on the look out for the specific piece of technology. Similarly, an exceptionally meritorious research can go totally unnoticed and under-appreciated by the industry if it has not been an item on the look-out-lists of the industry movers. Then, we all wait for decades until the industry catches up with the brilliance of the the original researchers.
On the same note, I recall one such invention that was not give due recognition for almost four decades. A landmark paper appeared on IEEE Circuits and Systems (CAS) journal in 1971 written by the exceptional engineer Dr. Leon Chua on a theoretical 4th circuit element which he named ‘Memristor’ to mean ‘Memory+Resistor’. Dr. Chua was so ahead of his time that the paper got rarely cited in next few decades.
The idea was lost in the wilderness until, one group of researchers in HP labs fabricated a two-terminal device which could relate the flux-linkage to the charge in 2008. In fact, the physical realization of memristive-behaviour required the dimensions/channel lengths to be lowered down to few-atoms in thickness which was not possible until after 2000s. So was the story of the re-birth of the memristor, and with it followed a boatload of new research projects, publications and fabrication attempts.
Industry and academia......they do not quite relate to each other in a rational manner. Nevertheless, we want them both.
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