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Updated: March 27, 2013 23:58 IST

Quantum computers turn mainstream

Quentin Hardy
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Nobel-laureate David Wineland works on an
AP
Nobel-laureate David Wineland works on an "ion trap" used to demonstrate the basic operations required for a quantum computer in this 2003 file photo.

Our digital age is all about bits, those precise ones and zeros that are the stuff of modern computer code.

But a powerful new type of computer that is about to be commercially deployed by a major United States military contractor is taking computing into the strange, subatomic realm of quantum mechanics. In that infinitesimal neighbourhood, common sense logic no longer seems to apply. A one can be a one, or it can be a one and a zero and everything in between all at the same time.

It sounds preposterous, particularly to those familiar with the yes/no world of conventional computing. But academic researchers and scientists at companies like Microsoft, IBM and Hewlett-Packard have been working to develop quantum computers.

Now, Lockheed Martin — which bought an early version of such a computer from the Canadian company D-Wave Systems two years ago — is confident enough in the technology to upgrade it to commercial scale, becoming the first company to use quantum computing as part of its business.

Sceptics say that D-Wave has yet to prove to outside scientists that it has solved the myriad challenges involved in quantum computation.

But if it performs, as Lockheed and D-Wave expect, the design could be used to supercharge even the most powerful systems, solving some science and business problems, millions of times faster than can be done today.

Ray Johnson, Lockheed’s chief technical officer, said his company would use the quantum computer to create and test complex radar, space and aircraft systems. It could be possible, for example, to tell instantly how the millions of lines of software running a network of satellites would react to a solar burst or a pulse from a nuclear explosion — something that can now take weeks, if ever, to determine.

“This is a revolution not unlike the early days of computing,” he said. “It is a transformation in the way computers are thought about.”

Many others could find applications for D-Wave’s computers.

Cancer researchers see a potential to move rapidly through vast amounts of genetic data. The technology could also be used to determine the behaviour of proteins in the human genome, a bigger and tougher problem than sequencing the genome. Researchers at Google have worked with D-Wave on using quantum computers to recognise cars and landmarks, a critical step in managing self-driving vehicles.

Optimal outcome

Quantum computing is so much faster than traditional computing because of the unusual properties of particles at the smallest level. Instead of the precision of ones and zeros that have been used to represent data since the earliest days of computers, quantum computing relies on the fact that subatomic particles inhabit a range of states.

Different relationships among the particles may coexist, as well. Those probable states can be narrowed to determine an optimal outcome among a near-infinitude of possibilities, which allows certain types of problems to be solved rapidly.

D-Wave, a 12-year-old company based in Vancouver, has received investments from Jeff Bezos, the founder of Amazon.com, which operates one of the world’s largest computer systems, as well as from the investment bank Goldman Sachs and from In-Q-Tel, an investment firm with close ties to the Central Intelligence Agency (CIA) and other government agencies.

‘Parallel development’

“What we’re doing is a parallel development to the kind of computing we’ve had for the past 70 years,” said Vern Brownell, D-Wave’s chief executive.

Mr. Brownell, who joined D-Wave in 2009, was until 2000 the chief technical officer at Goldman Sachs. “In those days, we had 50,000 servers just doing simulations” to figure out trading strategies, he said. “I’m sure there is a lot more than that now, but we’ll be able to do that with one machine, for far less money.”

Criticism

D-Wave, and the broader vision of quantum-supercharged computing, is not without its critics. Much of the criticism stems from D-Wave’s own claims in 2007, later withdrawn, that it would produce a commercial quantum computer within a year.

“There’s no reason quantum computing shouldn’t be possible, but people talked about heavier-than-air flight for a long time before the Wright brothers solved the problem,” said Scott Aaronson, a professor of computer science at the Massachusetts Institute of Technology. D-Wave, he said, “has said things in the past that were just ridiculous, things that give you very little confidence”.

But others say people working in quantum computing are generally optimistic about breakthroughs to come. Quantum researchers “are taking a step out of the theoretical domain and into the applied”, said Peter Lee, the head of Microsoft’s research arm, which has a team in Santa Barbara, California, pursuing its own quantum work. “There is a sense among top researchers that we’re all in a race.”

If Microsoft’s work pans out, he said, the millions of possible combinations of the proteins in a human gene could be worked out “fairly easily”.

Superposition and entanglement

Quantum computing has been a goal of researchers for more than three decades, but it has proved remarkably difficult to achieve. The idea has been to exploit a property of matter in a quantum state known as superposition, which makes it possible for the basic elements of a quantum computer, known as qubits, to hold a vast array of values simultaneously.

There are a variety of ways scientists create the conditions needed to achieve superposition as well as a second quantum state known as entanglement, which are both necessary for quantum computing. Researchers have suspended ions in magnetic fields, trapped photons or manipulated phosphorus atoms in silicon.

The D-Wave computer that Lockheed has bought uses a different mathematical approach than competing efforts.

In the D-Wave system, a quantum computing processor, made from a lattice of tiny superconducting wires, is chilled close to absolute zero. It is then programmed by loading a set of mathematical equations into the lattice. The processor then moves through a near-infinity of possibilities to determine the lowest energy required to form those relationships. That state, seen as the optimal outcome, is the answer.

The approach, which is known as adiabatic quantum computing, has been shown to have promise in applications like calculating protein folding, and D-Wave’s designers said it could potentially be used to evaluate complicated financial strategies or vast logistics problems.

No scientific data published

However, the company’s scientists have not yet published scientific data showing that the system computes faster than today’s conventional binary computers. While similar subatomic properties are used by plants to turn sunlight into photosynthetic energy in a few million-billionths of a second, critics of D-Wave’s method say it is not quantum computing at all, but a form of standard thermal behaviour. — New York Times News Service

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