Featured Research

from universities, journals, and other organizations

Physicists Measure Tiny Force That Limits How Far Machines Can Shrink

September 24, 2005
University of Arizona
University of Arizona physicists have directly measured how close speeding atoms can come to a surface before atom wavelengths change. Their research has huge implications for nanotechnology and atom optics.

Alex Cronin (left) and John Perreault make an adjustment on the atom interferometer that they used in making the first direct measurement of atom wavelength shift caused by the van der Waals interaction.
Credit: Image courtesy of University of Arizona

Related Articles

Theirs is a first, fundamental measurementthat confirms the idea that the wave of a fast-moving atom shortens andlengthens depending on its distance from a surface, an idea firstproposed by pioneering quantum physicists in the late 1920s.

Themeasurement tells nanotechnologists how small they can make extremelytiny devices before a microscopic force between atoms and surfaces,called van der Waals interaction, becomes a concern. The result isimportant both for nanotechnology, where the goal is to make devices assmall as a few tens of billionths of a meter, and for atom optics,where the goal is to use the wave nature of atoms to make more precisesensors and study quantum mechanics.

UA optical sciences doctoralcandidate John D. Perreault and UA assistant professor of physicsAlexander D. Cronin report the experiment in the Sept. 23 PhysicalReview Letters. The paper is online at http://xxx.lanl.gov/PS_cache/physics/pdf/0505/0505160.pdf

Perreaultand Cronin used a sophisticated device called an atom interferometer inmaking the measurement. Cronin brought the 12-foot-long device to UAfrom MIT three years ago. The atom interferometer was assembled over 15years with more than $2 million in research grants from the NationalScience Foundation, the UA and the Research Corp. Now in Cronin'slaboratory on the third floor of the UA's Physics and AtmosphericSciences Building, the machine is one of only a half-dozen suchinstruments operating in the United States and Europe. It splits andrecombines atom waves so that scientists can observe the position ofthe wave crests.

"Our research provides the first directexperimental evidence that a surface 25 nanometers away (25 billionthsof a meter) causes a shift in the atom wave crests," Perreault said."It shows that the van der Waals interaction may be a small scaleforce, but it's a big deal for atoms."

Perreault and Cronin foundthat atoms closer than 25 nanometers to a surface are very stronglyattracted to the surface because of the van der Waals interaction-- sostrongly that the atoms are accelerated with the force of a million g's.

A"g" is a term for acceleration due to gravity. One g is an everydayexperience -- it's the force a person feels from Earth's gravity. Aroller coaster rider might feel 3 to 4 g's for brief moments during aride. Fighter pilots can experience accelerations of up to 8 g forbrief periods during tactical maneuvers, but can black out if subjectedto 4 to 6 g's for more than a few seconds.

"We might say thatwhen an atom is between 10 and 20 nanometers from a surface, it getssucked toward the surface with a force a million times its weight,"Cronin said. "And when it gets closer, it gets pulled even harder."

Themomentary acceleration of the atom as it passes by the surface isexpressed in a famous equation which relates the speed of an atom toits wavelength, Cronin said. When atoms are accelerated and closer tothe surface, their wavelengths become shorter. When farther from asurface, atoms return to their original wavelength. Perreault andCronin used the atom interferometer to measure the wavelength shift.

Nanotechnologyresearch aims to build much smaller transistors and motors, forexample, than currently exist. Atom optics research aims to exploit thewave behavior of atoms in ways that will make more precise gyroscopesfor navigation, gravity gradiometers for subterranean mapping and otherfield sensors.

"I think the impact of our work stems from theintersection of the fields of atom optics and nanotechnology,"Perreault said. "It answers the question of how far you can miniaturizean atom optics device - for example, a device that guides atoms on achip to form a very tiny interferometer - before this nano-interactiondisrupts operations."

The idea that atoms behave as waves as wellas particles goes back to 1924. They're called "de Broglie waves" forearly 20th-century French quantum physicist Prince Louis-Victor deBrogli, who first proposed the concept of atom waves. Scientists havegrappled with the dual wave-particle nature of atoms for decades and,in the 1990s, they began chilling atoms to near absolute zero andstudying the wave properties of atoms in detail.

Story Source:

The above story is based on materials provided by University of Arizona. Note: Materials may be edited for content and length.

Cite This Page:

University of Arizona. "Physicists Measure Tiny Force That Limits How Far Machines Can Shrink." ScienceDaily. ScienceDaily, 24 September 2005. <www.sciencedaily.com/releases/2005/09/050923154827.htm>.
University of Arizona. (2005, September 24). Physicists Measure Tiny Force That Limits How Far Machines Can Shrink. ScienceDaily. Retrieved April 1, 2015 from www.sciencedaily.com/releases/2005/09/050923154827.htm
University of Arizona. "Physicists Measure Tiny Force That Limits How Far Machines Can Shrink." ScienceDaily. www.sciencedaily.com/releases/2005/09/050923154827.htm (accessed April 1, 2015).

Share This

More From ScienceDaily

More Matter & Energy News

Wednesday, April 1, 2015

Featured Research

from universities, journals, and other organizations

Featured Videos

from AP, Reuters, AFP, and other news services

Voice-Controlled GPS Helmet to Help Bikers

Voice-Controlled GPS Helmet to Help Bikers

Reuters - Innovations Video Online (Apr. 1, 2015) Motorcyclists will no longer have to rely on maps or GPS systems, both of which require riders to take their eyes off the road, once a new Russian smart helmet goes on sale this summer. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
Wound-Healing Laser Soon to Be a Reality Israeli Scientist

Wound-Healing Laser Soon to Be a Reality Israeli Scientist

Reuters - Innovations Video Online (Apr. 1, 2015) Israeli scientists says laser bonding of tissue allows much faster healing and less scarring. Amy Pollock has more. Video provided by Reuters
Powered by NewsLook.com
7-Year-Old Girl Gets 3-D Printed 'robohand'

7-Year-Old Girl Gets 3-D Printed 'robohand'

AP (Mar. 31, 2015) Although she never had much interest in prosthetic limbs before, Faith Lennox couldn&apos;t wait to slip on her new robohand. The 7-year-old, who lost part of her left arm when she was a baby, grabbed it as soon as it came off a 3-D printer. (March 31) Video provided by AP
Powered by NewsLook.com
Dutch Architects Show Off 3D House-Building Prowess

Dutch Architects Show Off 3D House-Building Prowess

Reuters - Innovations Video Online (Mar. 31, 2015) Dutch architects are constructing a 3D-printed canal-side home, which they hope will spark an environmental revolution in the house-building industry. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.


Breaking News:

Strange & Offbeat Stories

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News


Free Subscriptions

Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile

Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?

Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins