Boffins make a quantum leap towards superfast computers

Quantum computers could be produced with a decade after achievement

Oscar Quine
Friday 15 November 2013 20:08
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Scientists have succeeded in maintaining a so-called “quantum memory state” for a world record time of 39 minutes - opening the way for a new generation of superfast computers.

Researchers at Simon Fraser University in Canada said fragile “qubits” of information encoded into a silicon system had survived at room temperature for 100 times longer than previously observed.

The achievement led some experts to suggest we will now see the production of extremely fast quantum computers within a decade. While the shape these computers will take, and the way they will work, is unknown, they promise to significantly outperform today’s machines by exploiting the strange properties of subatomic particles.

“There’s been a rapid pace of progress and everybody expects that to continue,” said Stephanie Simmons, of Oxford University’s Materials department, who was involved in the research. “There’s a real sense of urgency and momentum in the field. I expect we will see these computers within my lifetime, I can say that,” she told The Independent.

Conventional computing is based on binary code, which sees data expressed as strings of 1s and 0s. As counterintuitive as it may sound, a qubit – a piece of quantum data held in the nucleus of an ion - can exist in a “superposition”, capable of being both 1 and 0 at the same time, which enables them to perform multiple calculations simultaneously.

Ms Simmonds said the research has two major implications: “We've set new records for how long we can hold on to qubits. In doing so we've hypothetically allowed for more accurate quantum control, which makes it a lot easier to build a quantum processor.

“Secondly, we've shown that a qubit superposition can be incredibly robust to temperature variations - from near-absolute zero all the way up to room temperature, which nobody ever really expected."

The team made the breakthrough by isolating a single phosphorous atom in pure silicon, causing it to exist in something approaching a suspended state.

They prepared the sample at -269C, close to absolute zero, the lowest temperature possible, before raising it to room temperature. The previous length of time for which a solid state system was held at room temperature is believed to be 25 seconds.

The researchers were quick to stress that many obstacles still have to be overcome before the first quantum computer can be built. But interest has gathered pace in recent years, with specially dedicated institutions being set up in Canada, Singapore and the Netherlands.

In numbers: Qubits

-269c Temperature the nuclei were cooled to before having the information inserted

25c Temperature the qubits system was raised to

25 seconds The previous record length of time that qubits of information survived

39 minutes The new record time for their survival

10bn The number of phosphorus ions used in the experiment

The study is published in the journal Science.

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