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Posts Tagged ‘atomic structure’

There is no spoon


Strength in Numbers: Physicists Identify New Quantum State Allowing Three — But Not Two — Atoms to Stick Together


July 4, 2012

ScienceDaily (July 3, 2012) — A Kansas State University-led quantum mechanics study has discovered a new bound state in atoms that may help scientists better understand matter and its composition.

Abstract rendering. (Credit: © John Denison / Fotolia)

The yet-unnamed bound state, which the physicists simply refer to as “our state” in their study, applies to three identical atoms loosely bound together — a behavior called three-body bound states in quantum mechanics. In this state, three atoms can stick together in a group but two cannot. Additionally, in some cases, the three atoms can stick together even when any two are trying to repel each other and break the connection.

“It’s really counterintuitive because not only is the pair interaction too weak to bind two atoms together, it’s also actively trying to push the atoms apart, which is clearly not the goal when you want things to stick together,” said Brett Esry, university distinguished professor of physics at Kansas State University and the study’s lead investigator.

Read more : http://www.sciencedaily.com/releases/2012/07/120703142515.htm

 

Quantum Researchers Able to Stop and Restart Light


Wednesday, 27 June 2012

‘In two independent experiments that defy the notions of Einstein, researchers have been able to stop, then restart a beam of light.

Ordinarily, light travels at the speed of 186,282 miles per second, but the research team of Lene Hau, a professor of physics at Harvard, who in 1999 was able to slow light down to 38 miles per hour, has been able to trap light in a cloud of sodium atoms super-cooled to near ‘absolute zero.’’

Read more: Quantum Researchers Able to Stop and Restart Light

In Metallic Glasses, Researchers Find a Few New Atomic Structures


“The fundamental nature of a glass structure is that the organization of the atoms is disordered-jumbled up like differently sized marbles in a jar, rather than eggs in an egg carton,” says Paul Voyles, the principal investigator on the research. (Credit: © marionbirdy / Fotolia)

ScienceDaily (May 11, 2012) — Drawing on powerful computational tools and a state-of-the-art scanning transmission electron microscope, a team of University of Wisconsin-Madison and Iowa State University materials science and engineering researchers has discovered a new nanometer-scale atomic structure in solid metallic materials known as metallic glasses.

Published May 11 in the journal Physical Review Letters, the findings fill a gap in researchers’ understanding of this atomic structure. This understanding ultimately could help manufacturers fine-tune such properties of metallic glasses as ductility, the ability to change shape under force without breaking, and formability, the ability to form a glass without crystalizing.

Glasses include all solid materials that have a non-crystalline atomic structure: They lack a regular geometric arrangement of atoms over long distances. “The fundamental nature of a glass structure is that the organization of the atoms is disordered-jumbled up like differently sized marbles in a jar, rather than eggs in an egg carton,” says Paul Voyles, a UW-Madison associate professor of materials science and engineering and principal investigator on the research.

Researchers widely believe that atoms in metallic glasses are arranged only as pentagons in an order known as five-fold rotational symmetry. However, in studies of a zirconium-copper-aluminum metallic glass, Voyles’ team found there are clusters of squares and hexagons-in addition to clusters of pentagons, some of which form chains-all located within the space of just a few nanometers. “One or two nanometers is a group of about 50 atoms-and it’s how those 50 atoms are arranged with respect to one another that’s the new and interesting part,” he says.

Source:
The above story is reprinted from materials provided byUniversity of Wisconsin-Madison. The original article was written by Renee Meiller.