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 Heating quantum matter: A novel view on topology
22.08.2017 | Université libre de Bruxelles

nachricht Engineering team images tiny quasicrystals as they form
18.08.2017 | Cornell University

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: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Cholesterol-lowering drugs may fight infectious disease

22.08.2017 | Health and Medicine

Meter-sized single-crystal graphene growth becomes possible

22.08.2017 | Materials Sciences

Repairing damaged hearts with self-healing heart cells

22.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>