Featured Research

from universities, journals, and other organizations

Gases In One Dimension -- Not Your Typical Desk Toy

Date:
April 13, 2006
Source:
Penn State
Summary:
Physicists at Penn State University have performed the first laboratory experiment with a system of many colliding particles whose motion never becomes chaotic. The achievement provides a deeper understanding of conditions that govern the boundary between order and chaos in physical systems. The research also has the potential to improve the accuracy of modern communication and navigation systems, which rely on high-precision gyroscopes or force sensors.

Images of quantum Newton's cradles during their first cycle of oscillation.
Credit: David Weiss, Penn State

Physicists at Penn State University have performed the first laboratory experiment with a system of many colliding particles whose motion never becomes chaotic. The achievement provides a deeper understanding of conditions that govern the boundary between order and chaos in physical systems. The research also has the potential to improve the accuracy of modern communication and navigation systems, which rely on high-precision gyroscopes or force sensors. The research will be published in the 13 April issue of the journal Nature.

Related Articles


"A fascinating thing about this system is the remarkable stability of its momentum profile, which does not change even after each atom in the system has collided thousands of times," says Professor of Physics David Weiss, leader of the research team. Unlike every-day experiences with colliding atoms--for example, a small heater that eventually warms the air in an entire room--Weiss's system does not reach the state physicists call thermal equilibrium, even after a long time. "We are not really making time stand still in our system--but it does look that way," Weiss says.

Weiss explains that his team has constructed a system that is integrable, meaning that it can be described by equations of motion that predict its future when the equations are solved in one direction, and its past when they are solved in the opposite direction. "Only a handfull of integrable many-body systems are known, and this is the first time that any of them has been observed experimentally," Weiss says. Now that such systems can be studied experimentally, the researchers hope to discover more about the factors that tip a complex system into chaos.

Weiss's group, which includes postdoctoral scholar Toshiya Kinoshita and graduate student Trevor Wenger, began the experiment by first constructing what they call a "Quantum Newton's Cradle," the atomic equivalent of the mesmerizing toy that has five steel balls suspended from strings arranged in a straight line. The toy is fascinating because, when a ball on one end is pulled to the side and released to swing to a collision with the other balls, the ball on the opposite end swings out but all the other balls remain in place. "Such striking behavior, where the momentum values do not change even though momentum is exchanged among the balls, occurs only in one dimension--a straight line. Collisions between particles in two or three dimensions quickly result in the familiar homogenized state of thermal equilibrium," Weiss explains.

"We built the Quantum Neuton's Cradle in order to answer the question: Does a 1-dimensional system of particles ever reach thermal equilibrium?," Weiss said. The device uses interfering beams of laser light to form an array of thousands of parallel, tube-shaped traps that force atoms to stay in one dimension. "Quantum mechanics ensures that the motion within each tube is strictly one-dimensional," Weiss explains. The researchers then loaded into each tube about 150 atoms that were chilled to extremely low temperatures, just billionths of a degree above absolute zero. Other laser beams set the trapped atoms in motion in one dimension, making half of them go to the right and half to the left. Each group then oscillates in the trap, colliding with the other group twice each cycle.

"The quantum Newton's cradle is just like a classical Newton's cradle, except that it's more perfectly one dimensional and instead of 5 balls there are hundreds," says Weiss. "Also, because it's a quantum system, the atoms often just go right through each other, which never happens with the executive desk toy. Another difference is that you can't buy the quantum Newton's cradle on the Internet."

"We set all the atoms oscillating in the trap with almost the same amplitude. We found that even after each atom has bounced off the other atoms 10,000 times, each still oscillates with the original amplitude," Weiss says. "By shutting off equilibration," Weiss says, "we can use 1-dimensional gases to gain insight into how equilibration occurs. Now that we've seen them not equilibrate, we are looking at what we need to do to make them equilibrate. Theory has guided experiment up to now, but experiments are now in a position to guide the theory. It's a fine example of the way scientific progress is made."

Potential applications of the Penn State experiments involve devices important to modern communication and navigation systems that sometimes can be limited in their accuracy by collisions among atoms. "Trapped atoms also can be used as precise force sensors, which can be limited in their sensitivity by collisions," Weiss adds. "Strict 1-dimensional trapping might completely suppress the harmful effects of collisions and significantly improve the precision of these devices.

This research was funded by the National Science Foundation.


Story Source:

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


Cite This Page:

Penn State. "Gases In One Dimension -- Not Your Typical Desk Toy." ScienceDaily. ScienceDaily, 13 April 2006. <www.sciencedaily.com/releases/2006/04/060412225434.htm>.
Penn State. (2006, April 13). Gases In One Dimension -- Not Your Typical Desk Toy. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/2006/04/060412225434.htm
Penn State. "Gases In One Dimension -- Not Your Typical Desk Toy." ScienceDaily. www.sciencedaily.com/releases/2006/04/060412225434.htm (accessed December 19, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Building Google Into Cars

Building Google Into Cars

Reuters - Business Video Online (Dec. 19, 2014) — Google's next Android version could become the standard that'll power your vehicle's entertainment and navigation features, Reuters has learned. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
AP Review: Nikon D750 and GoPro Hero 4

AP Review: Nikon D750 and GoPro Hero 4

AP (Dec. 19, 2014) — What to buy an experienced photographer or video shooter? There is some strong gear on the market from Nikon and GoPro. The AP's Ron Harris takes a closer look. (Dec. 19) Video provided by AP
Powered by NewsLook.com
Double-Amputee Becomes First To Move Two Prosthetic Arms With His Mind

Double-Amputee Becomes First To Move Two Prosthetic Arms With His Mind

Buzz60 (Dec. 19, 2014) — A double-amputee makes history by becoming the first person to wear and operate two prosthetic arms using only his mind. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com
Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) — The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary 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.

Save/Print:
Share:  

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



Save/Print:
Share:  

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