Local News - A Queen’s University physicist and a California colleague have designed a breakthrough device that set a new record for measuring the least amount of motion in human-made objects.

In a paper published this week in the prestigious science journal Nature, Dr. Robert G. Knobel of Queen’s and Dr. Andrew Cleland of the University of California present their findings.

“We have come close to the limit of how little something can move and still be measured,” Knobel said.

“This is something that is almost completely still and yet we are still able to measure its motion.”

The new technique has pushed the two physicists to the front of a world-wide race among scientists on “zero-point motion,” measuring movement at the brink of stillness.

They are also receiving international attention for their advance, which has important potential applications for the study of objects too small to be seen with the naked eye, including cells.

“This advance could lead to much more sensitive microscopes,” said the Queen’s physicist.

The findings open the door to new possibilities across a number of fields, including medicine, chemistry and electronics.

Knobel, who worked for three years on a post-doctoral degree in California with Cleland, was able to measure the vibration of a tiny object down to a ten-millionth of the width of a human hair – something physicists had never been able to do before – with the use of the new sensor device.

The sensor is made up of two different parts. The transistor, which is a highly sensitive amplifier, is situated next to a tiny vibrating bridge structure similar to a diving board fixed at both ends. The length of the vibrating bridge measures about one-twentieth of the width of a human hair.

“A large part of this experiment was fabricating this device because it is really small,” Knobel said.

“What we were trying to do is make the thing that is smallest and lightest and then measure its motion as carefully as possible.”

The bridge may be tiny, but building it was a monumental task.

“There were a lot of flops,” Knobel said.

It is an “exquisitely engineered device,” physicist Miles Blencowe at Dartmouth College wrote in a commentary accompanying the Nature report.

The experiment was designed to probe the boundary between the macroworld and the sub-atomic world, Knobel said.

Knobel notes that in everyday life, when something is cooled, we expect that it will stop moving or vibrating – like water freezing and becoming ice. But on a fundamental – quantum mechanical – level, interactions between atoms still continue.

“It is an interesting playground for physicists and engineers,” he said.

Knobel, who just last week arrived at Queen’s from California to become an assistant professor, said he will continue his experiments with measuring tiny amounts of movement to push the limits even further.

“What we’re trying to get to is the absolute limit of how little an object can move and still be measured,” he said.



With a file from CanWest News Service

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