Smallest Diamond Ring Could Help Computing

March 28, 2008 -- Scientists have made the world's smallest diamond ring, which could play a role in the future of computing.

At just 5 micrometers across and 300 nanometers thick, the ring is unlikely to fit on anyone's finger, say the Australian researchers who made it. The University of Melbourne researchers hope the tiny loop will let them manipulate single photons, the smallest 'packet' of light.

They hope the ring, which was carved from a slither of diamond, will help researchers build powerful computers that use the properties of quantum physics.

"For quantum information processing, diamonds have some truly unique possibilities," said Steven Prawer, whose team presented images of the ring at an American Physical Society meeting this month in New Orleans.

Scientists know in theory how quantum computers could take advantage of the rules of physics to carry out enormous numbers of processes at the same time. But building such a computer in the real world has been an enormous challenge. Diamonds could overcome some of the obstacles, Prawer says.

That's because they offer an ideal way to produce qubits, the quantum equivalent of the "bits" that store information on standard computers. Like normal bits, qubits can have two different values, either 0 or 1. But unlike their standard counterparts, qubits can also exist in a "superposition" of both states at once.

It turns out that tiny impurities in diamonds meet this criterion, and all the other requirements of qubits, extremely well, Prawer says.

"The diamond offers a fantastic platform in order to make qubits because diamond offers us a gift from nature," he said.

That gift comes about when a single nitrogen atom and a tiny gap disrupt the normal carbon structure of a diamond. Scientists call these nitrogen-vacancy centers, and by shining laser light onto one, researchers can produce single photons of red light in ways that are easy to manipulate and measure.

They can also do this at room temperature, something most other quantum systems can't do. The researchers have already used these properties of diamonds in the field of quantum cryptography, which aims to allow secure information to be sent and received using the properties of quantum physics.

Related Links:

ABC Science Online

Eric Bland's blog: What the Tech?

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American Physical Society