Physics research removes outcome unpredictability of ultracold atomic reactions

Aug 25, 2014
Probability density -- given by the radius of the surface points to the origin -- of an Efimov trimer state at different three-body geometries that are characterized by the polar angle -- indicated by the trimer legends. The azimuthal angle characterizes the permutation of three atoms. The key feature in the probability density is that unlike ordinary molecular binding that mostly has a single geometry, the Efimov trimer covers have a broad range of geometries. The atoms in such states behave more like in a fluid drop. Credit: Yujun Wang, Kansas State University.

Findings from a physics study by a Kansas State University researcher are helping scientists accurately predict the once unpredictable.

Yujun Wang, research associate with the James R. Macdonald Laboratory at Kansas State University, and Paul Julienne at the University of Maryland, looked at theoretically predicting and understanding that involve three at ultracold temperatures. Their findings help explain the likely outcome of a chemical reaction and shed new light on mysterious quantum states.

The scientific journal Nature Physics recently published their findings in the article "Universal van der Waals Physics for Three Cold Atoms near Feshbach Resonances."

In the theoretical study, Wang and Julienne developed a robust yet simple that successfully predicts what happens in atomic reactions at ultracold temperatures. Their model, which is considered the best available, accounts for spin physics of the atoms as well as the van der Waals force—the attractive long-range forces between the forming molecules.

"For a long time there has been the belief that this kind of reaction in three or more particles is too difficult to predict because the interaction is so complicated," Wang said. "Now, this research has shown consistent observations that indicate and imply that theoretical prediction is possible."

These findings can guide research in chemical engineering, molecular physics and other fields because the model gives scientists a largely accurate idea of how the atoms will bind to form a molecule, Wang said.

Additionally, their work may help scientists understand the Efimov effect.

The Efimov effect, which was first predicted in the early 1970s, is what happens when two atoms that normally repel each other become loosely bound when a third atom is introduced. The result is three atoms that all stick together despite trying to repel each other—a reaction that defies conventional knowledge.

"It's a very bizarre mechanical phenomenon in quantum mechanics that cannot be understood using the classical model of ," Wang said. "The details of the Efimov effect are seemingly random and therefore complicated to study. But, because we showed that our atomic model and calculations can pretty accurately predict the position of such molecular states, we have new knowledge that may help us bypass those old barriers."

Explore further: Physicists succeed in revealing the scaling behaviour of exotic giant molecules

More information: Nature Physics, (2014) DOI: 10.1038/nphys3071

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Macksb
not rated yet Aug 25, 2014
Good work. The full article is available on Arxiv. Google: Universal physics three ultracold atoms.
mikep608
1 / 5 (2) Aug 25, 2014
I would post something, but it's just easier to look at my webpage
https://www.faceb...timeline
mikep608
1 / 5 (2) Aug 25, 2014
"The Efimov effect, which was first predicted in the early 1970s, is what happens when two atoms that normally repel each other become loosely bound when a third atom is introduced. The result is three atoms that all stick together despite trying to repel each other—a reaction that defies conventional knowledge"

my webpage has a similar explanation for this

https://www.faceb...timeline
Whydening Gyre
5 / 5 (1) Aug 25, 2014
Yeah, but... the Wikipedia explanation( http://en.wikiped...ov_state ) actually said something that made sense...
Macksb
1 / 5 (2) Aug 26, 2014
I have commented on most of the Efimov articles on Physorg over the last 3 years. Circa 1967, Art Winfree described how systems of 3 periodic oscillators would organize themselves.

His organizational pattern is the same as the Efimov pattern. (See picture above.)

Winfree also explained that such organization would emerge from coordinated oscillations. They would coordinate the phases of their periodic oscillations so that each would be one-third out of phase with the other two.

As described in the Arxiv version mentioned in my post above, Wang and Julienne say that the Efimov state emerges from coordinated interaction among the vibronics of the Efimov atoms. Vibronics, a term derived from vibrations and electron, refers to the periodic oscillations of the nucleus and the electrons. The vibronics of each Efimov atom are coordinated with the other two atoms, by the phases of their vibronics. This confirms my posts to earlier Efimov articles.
mikep608
1 / 5 (2) Aug 26, 2014
I have commented on most of the Efimov articles on Physorg over the last 3 years. Circa 1967, Art Winfree described how systems of 3 periodic oscillators would organize themselves.

Winfree also explained that such organization would emerge from coordinated oscillations. They would coordinate the phases of their periodic oscillations so that each would be one-third out of phase with the other two.

As described in the Arxiv version mentioned in my post above, Wang and Julienne say that the Efimov state emerges from coordinated interaction among the vibronics of the Efimov atoms. Vibronics, a term derived from vibrations and electron, refers to the periodic oscillations of the nucleus and the electrons. The vibronics of each Efimov atom are coordinated with the other two atoms, by the phases of their vibronics. This confirms my posts to earlier Efimov articles.

THIS ALSO FOLLOWS A LOT OF MY LOGIC https://www.faceb...timeline
swordsman
not rated yet Aug 26, 2014
My investigations show that the forces between atoms are primarily electromagnetic. There are four Coulomb forces and two magnetic forces for the hydrogen atom. Larger atoms are more complex. These forces were analyzed using the SPICE computer program and were published in the Computing and Science and Engineering magazine, May/June 2012. A subsequent paper is yet to be published.
Aligo
1 / 5 (1) Sep 03, 2014
The Efimov effect is what happens when two atoms that normally repel each other become loosely bound when a third atom is introduced. The result is three atoms that all stick together despite trying to repel each other—a reaction that defies conventional knowledge

Actually it's not so difficult to understand it, if we realize the mass-energy equivalence, according to which the mass density of massive environment is proportional to it's energy density, divided with square of speed of energy spreading in this environment. Illustratively speaking, the vacuum is behaving like the foam, which gets more dense under shaking in similar way, like the soap foam and it attracts another particles to this place. At the case of vacuum this mass density is rather low, but the light in boson condensate propagates much more slowly. Inside of this environment every interaction between pair of atoms leads to exchange of virtual photons, the effective mass of which is able to attract another atom.