“It opens up much richer phenomena to explore,” said Cheng Chin, an assistant professor in physics at the University. Chin’s team conducted the experiment as the first step in a project to simulate the dynamics of electrons in a solid.
“How you can make the transition from a conducting material to a non-conducting material is difficult to conceive,” said Chin. But his team actually observed such a transition using super-cooled atoms to simulate the behavior of electrons.
“It’s nearly impossible to resolve the dynamics of electrons,” Chin said, because they move from atom to atom in trillionths of a second. The Chicago physicists dodged this problem by cooling a single layer of cesium atoms to temperatures near absolute zero (minus 459.67 degrees Fahrenheit). Then they magnetically controlled the motion of the atoms on a millisecond time scale (thousands of a second). This is a billion times slower than electrons move, but the physics remains the same.
“We made a thin film of atoms, and then we watched how they distributed themselves inside our chamber.”
What they observed confirmed a prediction that another team of scientists made in 2000: While the atoms are in a superfluid state (conducting), they experience very little repulsive force between each other. When moving freely, these atoms can become compressed with the application of pressure.
“There’s a certain mobility when you apply a force. You can easily compress a conducting sample,” Chin said.
But when the Chicago researchers applied a magnetic field, initiating a much greater repulsive force between the atoms, they became jammed and could not be deformed. The atoms had entered an incompressible insulating state.
Citation: Gemelke, Nathan; Zhang, Xibo; Hung, Chen-Lung; and Chin, Cheng, “In-situ Observation of Incompressible Mott-Insulating Domains of Ultracold Atomic Gases,” Nature, Aug. 20, 2009.
Funding sources: National Science Foundation, Defense Advanced Research Projects Agency, and the Grainger Foundation.
Steve Koppes | Newswise Science News
Smallest transistor worldwide switches current with a single atom in solid electrolyte
17.08.2018 | Karlsruher Institut für Technologie (KIT)
Protecting the power grid: Advanced plasma switch for more efficient transmission
17.08.2018 | DOE/Princeton Plasma Physics Laboratory
There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.
The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
20.08.2018 | Information Technology
20.08.2018 | Life Sciences
20.08.2018 | Information Technology