'Quantum computer' a stage closer with silicon breakthrough

Jun 23, 2010
The electron orbits a phosphorus atom embedded in the silicon lattice, shown in silver. The undisturbed electron density distribution, calculated from the quantum mechanical equations of motion is shown in yellow. A laser pulse can modify the electron’s state so that it has the density distribution shown in green. Our first laser pulse, arriving from the left, puts the electron into a superposition of both states, which we control with a second pulse, also from the left, to give a pulse which we detect, emerging to the right. The characteristics of this "echo" pulse tell us about the superposition we have made. Credit: UCL

The remarkable ability of an electron to exist in two places at once has been controlled in the most common electronic material - silicon - for the first time. The research findings - published in Nature by a UK-Dutch team from the University of Surrey, UCL (University College) London, Heriot-Watt University in Edinburgh, and the FOM Institute for Plasma Physics near Utrecht - marks a significant step towards the making of an affordable "quantum computer".

According to the research paper in Nature the scientists have created a simple version of Schrodinger's cat - which is paradoxically simultaneously both dead and alive - in the cheap and simple material out of which ordinary are made.

"This is a real breakthrough for modern electronics and has huge potential for the future," explained Professor Ben Murdin, Photonics Group Leader at the University of Surrey. "Lasers have had an ever increasing impact on technology, especially for the transmission of processed information between computers, and this development illustrates their potential power for processing information inside the computer itself. In our case we used a far-infrared, very short, high intensity pulse from the Dutch FELIX laser to put an electron orbiting within into two states at once - a so-called state. We then demonstrated that the superposition state could be controlled so that the electrons emit a burst of light at a well-defined time after the superposition was created. The burst of light is called a photon echo; and its observation proved we have full control over the of the atoms."

And the development of a silicon based "quantum computer" may be only just over the horizon. "Quantum computers can solve some problems much more efficiently than conventional computers - and they will be particularly useful for security because they can quickly crack existing codes and create un-crackable codes," Professor Murdin continued. "The next generation of devices must make use of these superpositions to do quantum computations. Crucially our work shows that some of the quantum engineering already demonstrated by atomic physicists in very sophisticated instruments called cold atom traps, can be implemented in the type of silicon chip used in making the much more common transistor."

Professor Gabriel Aeppli, Director of the London Centre for Nanotechnology added that the findings were highly significant to academia and business alike. "Next to iron and ice, silicon is the most important inorganic crystalline solid because of our tremendous ability to control electrical conduction via chemical and electrical means," he explained. "Our work adds control of quantum superpositions to the silicon toolbox."

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User comments : 8

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5 / 5 (3) Jun 23, 2010
Does anyone know how many breakthroughs we still need before we actually have one.
not rated yet Jun 23, 2010
As many as needed until someone developes a system that will operate at full capacity for long peroids of time without data corruption or catastrophic failure over a short peroid.
not rated yet Jun 23, 2010
That image looks like an olive with pimento and a toothpick... shaken not stirred, please.
5 / 5 (1) Jun 23, 2010
Is it at 2 places at the sametime ? or do we
really even have the ability to measure the
electron dipole timing ?
not rated yet Jun 23, 2010
Could they soon use graphene instead of silicon for even more conductivity or is it a different ball game altogether?
5 / 5 (2) Jun 23, 2010
@Kedas -- They need twice as many breakthroughs because they're dealing with quantum mechanics, where each breakthrough is a breakthrough and also not a breakthrough at the same time. ;)
Jun 24, 2010
This comment has been removed by a moderator.
not rated yet Jun 24, 2010
Does anyone know how many breakthroughs we still need before we actually have one.

Commercial avenues and real world practicality are key. Until the avenues of human ease and compatibility with all other components in society open up, technologies remain in the domain of academics. After enough years breakthroughs create enough pressure to warrant the opportunity cost of implementing them and people adjusting their own lives accordingly, hence the computer boom, mobile boom, tablet boom, and hopefully soon biotech, robotic, and nanotech.
not rated yet Jul 12, 2010
Could they soon use graphene instead of silicon for even more conductivity or is it a different ball game altogether?

Perhaps, but we have vast experience with silicon.

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