Quantum Computer Chip Realized In Silicon

Tuesday, September 4, 2012

 Quantum Computers
An international research collaboration led by scientists from the University of Bristol, UK, has developed a new approach to quantum computing that could lead to the mass-manufacture of new quantum technologies.
Scientists have constructed a new quantum computer chip in silicon that will enable the creation of completely secure mobile phones and ultra-fast computers with capabilities far beyond today’s devices.  This represents a major breakthrough towards the mass adoption of quantum computer technology.

The scientists from the University of Bristol’s Centre for Quantum Photonics developed a silicon chip that will pave the way to the mass-manufacture of miniature quantum chips. The announcement was made at the launch of the 2012 British Science Festival [4 to 9 September].

The leap from using glass-based circuits to silicon-based circuits is significant because making quantum circuits in silicon has the major advantage of being compatible with modern microelectronics. Silicon, of course, is the same material routinely used to build the tiny conventional electrical processors in all computers and smart phones. This breakthrough means the power of quantum processing will not require complicated ruby or diamond based architectures. Ultimately this technology could be integrated with conventional microelectronic circuits, and could one day allow the development of hybrid conventional / quantum microprocessors.

Unlike conventional silicon chips that work by controlling electrical current, these circuits manipulate single particles of light (photons) to perform calculations. These circuits exploit strange quantum mechanical effects such as superposition (the ability for a particle to be in two places at once) and entanglement (strong correlations between particles that would be nonsensical in our everyday world). The technology developed uses the same manufacturing techniques as conventional microelectronics, and could be economically scaled for mass production soon. These new circuits are also compatible with existing optical fibre infrastructure and are ready to be deployed directly with the internet, another key breakthrough application of the invention.

Mark Thompson, Deputy Director of the Centre for Quantum Photonics in the University's School of Physics, said: “Using silicon to manipulate light, we have made circuits over 1000 times smaller than current glass-based technologies. It will be possible to mass-produce this kind of chip using standard microelectronic techniques, and the much smaller size means it can be incorporated in to technology and devices that would not previously have been compatible with glass chips.

“This is very much the start of a new field of quantum-engineering, where state-of-the-art micro-chip manufacturing techniques are used to develop new quantum technologies and will eventually realise quantum computers that will help us understand the most complex scientific problems.”

Published in the New Journal of Physics the researchers have demonstrated quantum interference and manipulation of entanglement using silicon components just 10's micrometres in size.

The research – carried out in collaboration with high-tech companies Toshiba of Japan, Nokia of Finland and Oclaro of the UK, and with Heriot-Watt University in Scotland and Delft University in the Netherlands – is an essential step towards miniaturising optical quantum computers.

Along with recent demonstrations from the Bristol research group and other groups showing on-chip generation of photonics qubits and results from the US showing on-chip detection of single photons, the Bristol-lead research team now believes that all the key components are in place to realise a fully functioning quantum processor — a powerful type of computer that uses quantum bits (qubits) rather than the conventional bits used in today’s computers.

Quantum computers will have unprecedented computational power for tasks including search engines and the design of new materials, biology and pharmaceuticals. This work, carried out with collaborators including Heriot-Watt University in Scotland and Delft University in the Netherlands, is an essential step towards the miniaturisations of quantum technologies.

Fabricating quantum circuits in silicon has the huge advantage of compatibility with modern electronics. According to Jeremy O’Brien, physics professor at Bristol, quantum processors could be integrated with conventional microelectronic circuits within three to five years.

The new chip is made from silicon, like the microprocessors in all computers and smart phones. Unlike conventional silicon chips that work by controlling electrical current, the quantum chips manipulate particles of light, called photons, to perform calculations. A quantum computing device with 100 photons could in principle solve trillions of equations at the same time.

The new circuits are compatible with existing optical glass fibre infrastructure used in broadband communications, because they operate at the same wavelengths. “The global communications network, including the internet, is powered by fibre optics which use light to move information at high speed between countries, cities and buildings,” said Mark Thompson, deputy director of Bristol’s Centre for Quantum Photonics. “Our devices are directly compatible – in a sense they talk the same language.”

A quantum computer can solve complex problems that ordinarily take too long even for supercomputers. Tasks include financial risk analysis, object recognition in images, database searches and the design of new materials, drugs and clean tech devices.

“Just as wind tunnels are not used for aircraft designs any more but [have been] replaced by computer simulations, in the future we may be able to replace most chemistry labs with quantum computers,” says Prof O’Brien.

SOURCE  University of Bristol, The Globe and Mail

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