Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Rice physicists find reappearing quantum trios

Researcher Randy Hulet is from Rice University. Credit: Jeff Fitlow/Rice University
Researcher Randy Hulet is from Rice University. Credit: Jeff Fitlow/Rice University

Abstract:
Study of ultracold atoms proves theory about universal quantum mechanism.

Rice physicists find reappearing quantum trios

Houston, TX | Posted on December 11th, 2009

Using atoms at temperatures colder than deep space, Rice University physicists have delivered overwhelming proof for a 1970 theory that was largely scoffed at when it first appeared. In a paper available online in Science, Rice's team offers experimental proof of a universal quantum mechanism that causes trios of particles to appear and reappear at higher energy levels in an infinite progression. The triplets, or trimers, form in special cases where pairs cannot.

"It's such a remarkable phenomena," said team leader Randy Hulet. "There are examples, like the Borromean rings, where having a third component is crucial. Any two of the rings will unbind if the third is removed, and these trimers are similar. The particles want to bind, but no two can do it. They need the third one to make it happen."

The trimers were first predicted almost 40 years ago by theoretical physicist Vitaly Efimov. The most striking feature of Efimov's prediction was that the effect was both universal and repeating. That meant that the trimers could form from anything, be it as large as an atom or as small as a quark. And it also meant that Efimov's trimers would form repeatedly, up and down the energy scale in a stepwise fashion. Efimov, now at the University of Washington, even predicted the spacing in energy of the trimers; he said they would appear every time the binding energy increased by a factor of 22.7.

"A lot of people didn't believe him," said Hulet, Rice's Fayez Sarofim Professor of Physics and Astronomy. "That's partly because physicists can handle two-body problems quite well and many-body problems fairly well, but when there are just a few objects, like the three bodies in these Efimov trimers, there are just too many variables."

As Hulet points out, there is still no general mathematical solution for the most classic of all "three-body" problems -- the sun-Earth-moon problem.

"You can do a numerical calculation, of course," he said. "You can calculate to arbitrary precision what the sun, Earth and moon are doing relative to one another at any given time, but you cannot write out a formula for that on paper. There is no general solution for that or any other three-body problem."

What Efimov offered in 1970 was not a general solution for the three-body problem, but it was the next-best thing -- a universal relationship that would hold true for any particle but only under a particular set of circumstances.

Hulet said nuclear physicists tried for decades to find experimental evidence of Efimov trimers using nuclear particles, but they found that there wasn't a strong enough attractive interaction between the particles to satisfy the conditions laid out by Efimov.

In the 1980s, physicists began using a combination of powerful lasers and magnetic fields to trap and cool atoms to ultracold temperatures. As thermodynamic heat is driven from the atoms, they move slower and slower. That let physicists study atoms in a new way, and as the techniques progressed, physicists were eventually able to remove so much thermodynamic energy from these trapped atoms that they began to manifest the effects of quantum physics.

Efimov trimers are one manifestation of quantum physics, and Hulet said a number of research groups worldwide have been racing to study them for several years. The first Efimov trimer was observed in 2006, and the first set of two connected trimers was observed in early 2009.

In their experiments, Hulet, postdoctoral researcher Scott Pollack and graduate student Dan Dries designed a test for Efimov's prediction about universal scaling -- the notion that trimers emerged again and again in a stepwise fashion. The team used a property of ultracold atoms called a "Feshbach resonance" to tune the interactions between lithium atoms. As they dialed up and down the energy scale, they saw Efimov's trimers appear and reappear again and again. The team confirmed another Efimov prediction as well by finding four-body "tetramers" in close proximity to each trimer. In all, Hulet, Pollack and Dries found 11 different signatures for trimers and tetramers, each exactly where Efimov and others had predicted.

Efimov was in the room when Hulet presented the first results of the tests at a scientific meeting in Rome.

"He was so excited that he came up and gave me a high five after the talk," Hulet said. "In his original paper, he had a figure that looked just like what we had found. It was such an amazing prediction, and to see it borne out like this is very special."

Hulet's research is sponsored by the National Science Foundation, the Office of Naval Research, the Keck Foundation and the Welch Foundation.

####

About Rice University
Located in Houston, Rice University is consistently ranked one of America's best teaching and research universities. Known for its "unconventional wisdom," Rice is distinguished by its: size -- 3,102 undergraduates and 2,237 graduate students; selectivity -- 12 applicants for each place in the freshman class; resources -- an undergraduate student-to-faculty ratio of 5-to-1; sixth largest endowment per student among American private research universities; residential college system, which builds communities that are both close-knit and diverse; and collaborative culture, which crosses disciplines, integrates teaching and research, and intermingles undergraduate and graduate work.

For more information, please click here

Contacts:
Jade Boyd
Associate Director and Science Editor
Office of Public Affairs/News & Media Relations
Rice University
(office) 713-348-6778
(cell) 713-302-2447

www.rice.edu

Copyright © Rice University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Organometallics welcomes new editor-in-chief: Paul Chirik, Ph.D. July 22nd, 2014

The Hiden EQP Plasma Diagnostic with on-board MCA July 22nd, 2014

Iran to Hold 3rd Int'l Forum on Nanotechnology Economy July 22nd, 2014

Nanometrics Announces Upcoming Investor Events July 22nd, 2014

Discoveries

Researchers create vaccine for dust-mite allergies Main Page Content: Vaccine reduced lung inflammation to allergens in lab and animal tests July 22nd, 2014

NIST shows ultrasonically propelled nanorods spin dizzyingly fast July 22nd, 2014

Penn Study: Understanding Graphene’s Electrical Properties on an Atomic Level July 22nd, 2014

NUS scientists use low cost technique to improve properties and functions of nanomaterials: By 'drawing' micropatterns on nanomaterials using a focused laser beam, scientists could modify properties of nanomaterials for effective applications in photonic and optoelectric applicat July 22nd, 2014

Announcements

Nanometrics Announces Upcoming Investor Events July 22nd, 2014

Bruker Awarded Fourth PeakForce Tapping Patent: AFM Mode Uniquely Combines Highest Resolution Imaging and Material Property Mapping July 22nd, 2014

NIST shows ultrasonically propelled nanorods spin dizzyingly fast July 22nd, 2014

Penn Study: Understanding Graphene’s Electrical Properties on an Atomic Level July 22nd, 2014

Quantum nanoscience

Physicists Use Computer Models to Reveal Quantum Effects in Biological Oxygen Transport: The team solved a long-standing question by explaining why oxygen – and not deadly carbon monoxide – preferably binds to the proteins that transport it around the body. July 17th, 2014

Bending the rules: A UCSB postdoctoral scholar in physics discovers a counterintuitive phenomenon: the coexistence of superconductivity with dissipation June 29th, 2014

Singapore Researchers Use FEI Titan S/TEM to Link Plasmonics with Molecular Electronics: As described in the March 28 issue of Science, researchers discover quantum plasmonic tunneling – a phenomenon that may eventually lead to new, ultra-fast electrical circuits June 24th, 2014

New quantum mechanism to trigger the emission of tunable light at terahertz frequencies June 18th, 2014

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE