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Size Matters

Mini Issue: Nanotechnology


Published June 18, 2008 at 5:49 a.m.

When it comes to working with ultra-small objects, very few people delve into as tiny a realm as Dennis Clougherty. The denizens of his workaday world — solitons, polarons, superconducting fullerides and colossal manganites — sound like characters out of Star Trek. Indeed, as a theoretical physicist, Clougherty boldly goes where few of us have gone before: namely, down to the quantum level, where the laws of Newtonian physics fly apart.

Clougherty chairs the physics department at the University of Vermont, where he specializes in condensed matter theory. In layman’s terms, his job is to try to understand and predict the properties of solids and liquids at the quantum scale, where particles are measured in nanometers, or billionths of a meter.

As a frame of reference, think of a nanometer as the distance a whisker grows in the time it takes to raise a razor to one’s face. Or, to use a structure from the field of quantum mechanics itself, imagine a soccer-ball-shaped molecule composed of 60 carbon atoms. This “buckyball,” as it’s called, measures 1 nanometer in diameter. To compare a buckyball with a soccer ball, Clougherty explains, is equivalent to comparing a real soccer ball with the planet Neptune.

Only at such an infinitesimal scale, Clougherty adds, do we encounter the “more correct truth” embodied in quantum mechanics. That is, the laws of nature we’re accustomed to using in the macroscopic world — such as gravity and electromagnetism — simply don’t apply there. As he puts it, “You have to put aside your classical intuition. It will mislead you.”

For example, “When you cool atoms to very low temperatures, they tend not to stick to other surfaces,” Clougherty continues. “This is classically counterintuitive. You’d suspect cold atoms are moving very slowly, so it would be very easy to get them to stick to surfaces. And yet, these cold atoms tend to be reflected from surfaces. Why is that?”

Admittedly, much of Clougherty’s research involves complex mathematics found only in the rarefied scientific communities of places like Harvard and MIT — two schools that Clougherty attended. However, there are also many everyday examples of nanostructures that are easily observable with the human eye.

For instance, think of the iridescent blue in the wings of a Morpho butterfly, or the water-repellence of kale leaves. Both, Clougherty points out, are natural examples of nanostructures. “We see the effects of quantum mechanics all around us,” he says. “We just don’t associate them as such.”

In the realm of human technology, Clougherty’s work has applications in the design of optical electronic devices, such as LCD screens and television sets. It could also come in handy in the future development of a “quantum computer,” which may one day perform highly complex functions that are simply unimaginable using today’s digital machines.

Clougherty devotes considerable time — and his vast scientific knowledge — to devising ways to get children interested in math and science. For instance, he’s done presentations at Burlington schools where he drops marshmallows into liquid nitrogen and shatters them against the wall like light bulbs.

“There are things that you can point to, like superconductivity and superfluidity, that really get kids excited,” he says. “When we levitate magnets, you should see them jump out of their seats.”