For decades, the mind-boggling aspects of quantum theory tormented Albert Einstein, who could never get his mind around what he famously called “spooky action at a distance”.
“The nonsensical quantum world seems so different from the familiar one around us,” says Jeremy O’Brien, head of Bristol University’s Centre for Quantum Photonics in the UK. “Now we are working out what we can usefully do with it.”
Prof O’Brien is a leading figure in the world of quantum computing – a research field that promises to transform information technology over the next few decades, as electronic computing reaches the limits of what is physically possible with conventional chips and circuitry.
His own research group, working with colleagues at Tohuku University in Japan, the Weizmann Institute in Israel and Twente University in the Netherlands, announced on Friday what Jonathan Matthews of Bristol called “a landmark on the way to practical quantum computing”.
The international team published in the journal Science – and described at the British Science Festival in Birmingham – the first “photonic” chip that makes use of the weird properties of the quantum world, such as particles that exist in several places at the same time and interact instantly with each other. The chip works on light rather than electricity – sending “entangled” photons down networks of miniature circuits.
The Bristol-led team is part of a huge worldwide research effort in quantum computing that has been gathering momentum over the past few years.
Quantum physics is already used for secure communications, because any attempt to eavesdrop or interfere with messages can be detected instantly.
But a full-scale quantum computer is still some way off. Many experts would still put it more than 20 years in the future but Prof O’Brien says a working prototype that could outperform a conventional computer could be running in five to 10 years.
Applications suited to quantum computing are those that require huge numbers of operations to be performed simultaneously. An example with great commercial potential is database searching – looking for tiny pieces of information across billions of websites.
Governments and companies worldwide are investing hundreds of millions of dollars a year on quantum computing research. The quantum chip developed at Bristol was funded by a group of agencies, including the UK Engineering and Physical Sciences Research Council, the European Research Council and the US Intelligence Advanced Research Projects Activity.
In addition, Nokia of Finland is funding the Bristol researchers, because it sees long-term applications in mobile computing, while Toshiba is supporting its Japanese colleagues.
With much of Silicon Valley focused on cutting costs and outsourcing production of chips to Asia, most current research work is done by Intel and IBM, working with US universities.
Intel, the world's largest chipmaker, has been developing silicon photonics for several years. But its use of laser light has so far been confined to replacing the copper wires that pass data between components in a computer. Intel’s technology is not capable of being used to speed calculations inside a microprocessor.
Intel is still focused on reducing the size of circuit widths to continue improving the performance of conventional computing.
Silicon chips currently have circuit widths of as little as 32 billionths of a metre, or nanometres, with 22-nanometre chips on the way next year. It expects to reduce circuits to eight nanometres by 2017. Quantum photonics may represent the future of computing but there is still life in conventional silicon electronics.
Additional reporting by Chris Nuttall
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