A team of Boston University physicists led by Assistant Professor Pritiraj Mohanty developed a nanomechanical oscillator – an antenna-like sliver of silicon one-tenth the width of a human hair. With two sets of protrusions, much like the teeth from a two-sided comb, the antenna not only exhibits the first quantum nanomechanical motion, but is also the world’s fastest moving nanostructure. Additionally, the antenna, which is comprised of 50 billion atoms, is so far the largest structure to display quantum mechanical movements.

Operating at gigahertz speeds, the technology couiould help further miniaturize wireless communication devices like cell phones, which exchange information at gigahertz frequencies. But, more important to the researchers, the oscillator lies at the cusp of classic physics, what people experience everyday, and quantum physics, the behavior of the molecular world.

At a certain frequency, the paddles begin to vibrate in concert, causing the central beam to move at that same high frequency, but at increased and easily measured amplitude. Where each paddle moves only about a femtometer - roughly the diameter of an atom’s nucleus - the antenna moves over a distance of one-tenth of a picometer, a tiny distance that still translates to a 100-fold increase in amplitude.

“It’s a truly macroscopic quantum system,” said Alexei Gaidarzhy, a graduate student in the BU College of Engineering’s Department of Aerospace and Mechanical Engineering. The device is also the fastest of its kind, oscillating at 1.49 gigahertz, or 1.49 billion times a second, breaking the previous record of 1.02 gigahertz achieved by a nanomachine produced by another group.

Find out more at: http://nano.bu.edu

The nanomechanical structure fabricated by the Mohanty group at Boston University consists of a central silicon beam, 10.7 microns long and 400 nm wide, that bears a “paddle” array 500 nm long and 200 nm wide along each side.