Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

MIT physicists create clouds of impenetrable gases that bounce off each other

14.04.2011
When one cloud of gas meets another, they normally pass right through each other. But now, MIT physicists have created clouds of ultracold gases that bounce off each other like bowling balls, even though they are a million times thinner than air — the first time that such impenetrable gases have been observed.

While this experiment involved clouds of lithium atoms, cooled to near absolute zero, the findings could also help explain the behavior of similar systems such as neutron stars, high-temperature superconductors, and quark-gluon plasma, the hot soup of elementary particles that formed immediately after the Big Bang. A paper describing the work will appear in the April 14 issue of Nature.

The researchers, led by MIT assistant professor of physics Martin Zwierlein, carried out their experiment with an isotope of lithium that belongs to a class of particles called fermions. All building blocks of matter — electrons, protons, neutrons and quarks — are fermions.

Different states of fermionic matter are distinguished by their mobility. For example, electrons can be mobile, as in a metal; immobile, as in an insulator; or flow without resistance, as in a superconductor. However, for many types of material, including high-temperature superconductors, it is not known what circumstances induce fermions to form a given state of matter. This is especially true of materials with strongly interacting fermions, meaning they are more likely to collide with each other (also called scattering).

In this study, the researchers set out to model strongly interacting systems, using lithium gas atoms to stand in for electrons. By tuning the lithium atoms' energy states with a magnetic field, they made the atoms interact with each other as strongly as the laws of nature allow, meaning that they scatter every time they encounter another atom.

To eliminate any effects of heat energy, the researchers cooled the gas to about 50 billionths of one Kelvin, close to absolute zero (-273 degrees Celsius). They used magnetic forces to separate the gas into two clouds, labeled "spin up" and "spin down, then made the clouds collide in a trap formed by laser light. Instead of passing through each other, as gases would normally do, the clouds repelled in dramatic fashion.

"When we saw that these ultra dilute puffs of gas bounce off each other, we were completely amazed," says graduate student Ariel Sommer, lead author of the Nature paper.

The gas clouds did eventually diffuse into each other, but in several cases it took an entire second or more — an extremely long time for events occurring at microscopic scales.

The research, conducted at the MIT-Harvard Center for Ultracold Atoms, is part of a program aimed at using ultracold atoms as easily controllable model systems to study the properties of complex materials, such as high-temperature superconductors and novel magnetic materials that have applications in data storage and improving energy efficiency.

In future work, the researchers plan to confine the lithium gases to two-dimensions, which will allow them to simulate the two-dimensional state in which electrons exist in high-temperature superconductors.

Their work can also be used to model the behavior of other strongly interacting systems, such as high-density neutron stars, which are only a few tens of kilometers in diameter but more massive than our sun.

Another substance that interacts as strongly as the atoms in the ultracold lithium gas clouds created at MIT is quark-gluon plasma, which existed at the universe's formation and has been recreated in particle colliders by colliding atomic nuclei at energies corresponding to a trillion degrees.

Written by Anne Trafton, MIT News Office

Caroline McCall | EurekAlert!
Further information:
http://www.mit.edu

More articles from Physics and Astronomy:

nachricht New quantum phenomena in graphene superlattices
19.09.2017 | Graphene Flagship

nachricht Solar wind impacts on giant 'space hurricanes' may affect satellite safety
19.09.2017 | Embry-Riddle Aeronautical 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: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

Im Focus: Artificial Enzymes for Hydrogen Conversion

Scientists from the MPI for Chemical Energy Conversion report in the first issue of the new journal JOULE.

Cell Press has just released the first issue of Joule, a new journal dedicated to sustainable energy research. In this issue James Birrell, Olaf Rüdiger,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

New quantum phenomena in graphene superlattices

19.09.2017 | Physics and Astronomy

A simple additive to improve film quality

19.09.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>