Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Extremely cold molecules created by Sandia and Columbia University researchers

15.12.2003


Dave Chandler aligns mirrors used to direct laser beams into an apparatus that generates very cold molecules and measures their velocity.
Credit: Sandia Corporation


Colors of the ball indicate the number of molecules at a given velocity. The bright spot at the top of the image represents molecules moving with less than 15 M/Sec, with the intensity of the spot proportional to the number moving that slowly. The density of slow molecules is approximately 108 molecules per cm3.
Credit: Sandia Corporation


Using a method usually more suitable to billiards than atomic physics, researchers from Sandia National Laboratories and Columbia University have created extremely cold molecules that could be used as the first step in creating Bose-Einstein molecular condensates. The work is published in the Dec. 12 Science.

The serendipitous achievement came when researchers at Sandia’s Livermore, Calif., and Columbia University, studying collisional energy transfer between a beam of atoms intersecting a beam of molecules, noted that a certain number of collisions occurred -- as they might between two billiard balls -- at exactly the right velocity for molecules to become motionless.

A motionless molecule is a cold molecule, according to laws of physics.



The study had led to a new technique for cooling molecules to millikelvin (a thousandth of a degree Kelvin above absolute zero) temperatures -- a first crucial step toward molecular ultra-coldness.

Though they were experts in neither cold molecules nor cold atoms, the researchers knew that atoms cooled to the nanokelvin (a billionth of a degree Kelvin) temperature range had been achieved several years ago with interesting basic-science results.

One product of the study of cold atoms is a new state of matter called a Bose-Einstein condensate. Certain atoms, bosons, can condense at a very low temperature and act as a single atom -- a fact which some researchers claim may lead to as many new developments as the first laser, originally only a scientific curiousity.

"Our technique has promise to be developed into a first step in the cooling process needed for a molecular Bose-Einstein condensate," says Sandia researcher and principal investigator Dave Chandler. The work is co-authored by Sandia post-doc Mike Elioff and James Valentini of Columbia University.

Very cold atoms and molecules may one day be used as individual yes/no switches (called Q-bits) in computers whose power our present-day imaginations are only beginning to grasp as well as precision gravity detectors that could perhaps locate underground caverns, says Chandler.

The main method used to achieve atomic ultra-cooling to the microkelvin temperature range -- the same preliminary cooling range as the Sandia technique -- makes use of laser beams that intersect at a point. An atom, possessing the appropriate absorption characteristics, passing through that point in effect stands still, like a kid in a dodge-ball game struck from all sides with balls. Transfixed by pressure from the beams, the atom becomes almost motionless.

The problem in cooling molecules by the laser method is that while some atoms possess characteristics that can be harmonically matched by a laser frequency, like the same note played by two pianos, molecular energy frequencies are more complex. This complexity makes them unsuitable for this type of laser cooling.

This leaves the field open for other techniques to be developed for the preliminary cooling of molecules. There have been four or five other techniques, published recently, that have had some level of success at cooling molecules. The most successful method to date has been the welding of ultracold atoms together to make ultracold molecules.

"Our atomic/molecular beam intersection method is inefficient, it’s true," says Chandler. "We only manage to cool one molecule in a million. But -- inefficient or efficient -- we generate cold molecules. With some improvements, we hope to be able to make substantial numbers of cold molecules."

Molecules are cheap, he says, so getting one in a million (1 in 106) cooling collisions out of the 1015 total collisions per second the molecules undergo in the beams doesn’t bother him.

This first-step method -- the only one to rely solely on the masses of the atoms and molecules involved -- could be useful in slowing down the speed of a variety of molecules sufficiently such that magnetic or electrical traps can be used to cool molecules further. Without prior slow-down, molecules would escape these relatively weak traps, like molecules of water rising from the surface of the hot coffee. Cold coffee evaporates fewer molecules.

Instruments in Chandler’s lab, working at their resolution limit, show selected molecules in the intersecting beams slowing from 600 meters/sec to 15 meters/sec. The group’s calculations indicate the speed to be on the order of 4 meters/sec. This average speed for the molecules is equivalent to a temperature on the tens of milliKelvin level -- that is, several thousandths of a degree above the universe’s absolute zero of -273 Celsius.

The last ninety nine yards, so to speak, are the hardest: Bose-Einstein condensates exist in the nanokelvin range, six orders of magnitude colder.


The basic-science work, funded by DOE’s Basic Energy Sciences, focuses on understanding how energy flows between molecules for a better understanding of heat transfer.


Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin company, for the U.S. Department of Energy’s National Nuclear Security Administration. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies, and economic competitiveness.

Sandia media contact:
Neal Singer, nsinger@sandia.gov, 505-845-7078

Neal Singer | Sandia Corporation
Further information:
http://www.sandia.gov/news-center/news-releases/2003/physics-astron/cold.html
http://www.sandia.gov

More articles from Physics and Astronomy:

nachricht Quantum optics allows us to abandon expensive lasers in spectroscopy
22.11.2017 | Lomonosov Moscow State University

nachricht Nano-watch has steady hands
22.11.2017 | University of Vienna

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Corporate coworking as a driver of innovation

22.11.2017 | Business and Finance

PPPL scientists deliver new high-resolution diagnostic to national laser facility

22.11.2017 | Physics and Astronomy

Quantum optics allows us to abandon expensive lasers in spectroscopy

22.11.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>