Quantum computers will one day make today’s supercomputers look like children’s toys, so great is their processing potential. And yet the quantum computers built so far have had little more processing power than a handheld calculator.

The difficulty is in being able to handle enough quantum bits of information (qubits) to do anything useful. Qubits are notoriously fragile. Sneeze and they decohere, leaking their valuable information into the environment. And this raises the fundamental dichotomy that quantum engineers face. They need quantum bits that can be poked and prodded into performing calculations in concert with other qubits and yet robust enough to survive over long periods of time.

Now Marshall Stoneham and pals from University College London say they’ve hit upon the ideal material in which to do all this: diamond.

Yep, crystalline carbon containing nitrogen vacancies can store qubits for relatively long periods of time and can house a relatively large number of qubits in a small volume. They can be addressed relatively easily using photon guns. And in diamond, qubits can become entangled which allows the information they contain to be transferred and processed.

And get this: Stoneham and co say this can all be done at room temperature.

Stoneham and co say that because of these factors the prospects for diamond look promising (although there are a number of important practical issues that need to be overcome before we’ll see these kinds of devices doing anything useful).

So does that mean that diamond will play the role in the quantum computing industry that silicon plays in the the conventional computer world?

It’s too early to say. There are so many technologies competing for the quantum computing crown that it’d be crazy to back one horse right now.

Having said that, a betting man might wager that quantum computers will be based on a photon-based technology. The current favourite involves non-linear optics, but diamonds could play a role. In fact they may be ideally suited for these kinds of optical systems.

Diamonds are a girl’s best friend, especially if she’s a quantum engineer.

Ref: arxiv.org/abs/0904.4895: Could One Make a Diamond-based Quantum Computer?