Kiwis control atoms in new breakthrough

An Otago University team of physicists, led by Dr Mikkel Andersen, draw on seven lasers, with components from compact disc players and precision mirrors. Photo / Supplied

Kiwi scientists have found an intriguing new way to control individual atoms, in a discovery a decade in the making and which could boost development of super-fast quantum computers to crunch extremely complex calculations.

The new research by the team of six Otago University physicists follows a global breakthrough in 2010, when they isolated and captured a neutral rubidium-85 atom, and then photographed it for the first time.

The group, led by Dr Mikkel Andersen, draw on seven lasers, with components from compact disc players and precision mirrors.

They work in an air-conditioned laboratory from which as many kinds of "noise" - electromagnetic, sound, temperature contrasts - that can affect the equipment and results have been minimised or eliminated using a little Kiwi ingenuity.

"We cool the atoms, hold them, change how they affect each other and make them visible by shining laser light, with different frequency and intensity, on them," Andersen said.

"We make repeated use of the phenomenal degree of control one can have over the frequency of laser light, which is a truly astounding feature of lasers."

Andersen said Kiwi ingenuity came into play when his team was faced with the fact it didn't have a low-noise laboratory that would typically be a necessity for such experiments.

"Naturally, finding out how to do things that have never been done before involves lots of hard work."

The tables on which the experiment had been built float on air, which was one way of keeping down the noise.

Dropping the temperature of the atom to almost absolute zero, an astonishing minus 273C, eliminated its random wobbling, allowing it to reach a quantum state with high purity.

This represented the ultimate control over individual atoms, Andersen said.

"We are pushing the boundaries for the level of control that scientists can have over microscopic systems.

"Technical revolutions our society has undergone in past decades largely, if not entirely, originate from being able to control systems at a smaller and smaller scale.

"This has been a long journey. This is what we have been trying to get to for 10 years."

Andersen said their results of the work, supported by a $717,000 Marsden Fund grant, could be beneficial in the future development of a wide range of technologies, including quantum computers.

"Time will tell what the applications will be. It is likely the main applications will be in technologies we have not yet thought about."

Further work would involve investigating how two atoms being brought together could exchange properties, and building molecules in particular quantum states from individual atoms.