Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Universal Three-body Relation: Heidelberg physicists succeed in revealing the scaling behaviour of exotic giant molecules

21.07.2014

When a two-body relation becomes a three-body relation, the behaviour of the system changes and typically becomes more complex.

While the basic physics of two interacting particles is well understood, the mathematical description of a three- or many-body system becomes increasingly difficult, such that calculating the dynamics can blast the capacities of even modern super computers.


Schematic representation of Efimov trimers formed from two caesium atoms and one lithium atom.

Picture credits: Juris Ulmanis

However, under certain conditions, the quantum mechanical three-body problem may have a universal scaling solution. The predictions of such a model have now been confirmed experimentally by physicists of Heidelberg University. The scientists under Prof. Dr. Matthias Weidemüller investigated three-particle molecules, known as trimers, under exotic conditions. The scientific results were published in “Physical Review Letters”.

The scientific work done in Heidelberg is based on a theory which was posed by the Russian physicist Vitaly Efimov more than 40 years ago. It focuses on finding physical laws capable of predicting the behaviour and energy states of an arbitrary number of particles.

... more about:
»Efimov »Physics »Relation »energy »evidence »prediction

According to Efimov’s prediction, bound states of three atoms can be universally described under certain conditions. The scientist found that infinitely many quantum mechanical bound states for the “ménage à trois” exist, even if two of the atoms cannot bind together. These so-called Efimov trimers are formed due to the long-range quantum mechanical interaction and they are completely independent of the underlying type of the three interacting particles.

Prof. Weidemüller says that Efimov’s prediction was considered “exotic” for a long time, since the conditions under which these molecular three-body bound states exist seemed unattainable in research. “Physicists with different scientific backgrounds have tried in vain to find signatures of the Efimov trimers,” explains the Heidelberg scientist. It was only about ten years ago that scientists from Innsbruck were able to provide clear evidence for these trimers in systems consisting of three identical atoms.

Shortly afterwards, physicists working with Prof. Dr. Selim Jochim in Heidelberg succeeded in measuring the exact binding energy of the Efimov trimers. In the course of scientific work performed at the Center for Quantum Dynamics and the Institute for Physics of Heidelberg University, further properties of the exotic Efimov trimers were investigated. To this end, the researchers cooled a gas of two different atomic species – caesium and lithium – to temperatures close to absolute zero. At the same time, they took care to precisely control the interaction between these lithium and caesium atom pairs.

In an ultra-high vacuum chamber the atoms were cooled solely by laser light and stored by light forces in a focused laser beam for several seconds. The coupling strength between the atoms can then be controlled by changing the magnetic field. For this Prof. Weidemüller’s team made use of what are known as atomic scattering resonances. The evidence of the trimers is based on the decay into their three components at a well-defined coupling strength. The strength of this coupling scales independently of the respective trimer bound state according to a purely numeric scaling factor. “We proved that the universal scaling is also valid in systems with different atoms,” says Rico Pires, who is working on his dissertation in Prof. Weidemüller’s team.

These scientists also succeeded in confirming that the scaling factor changes for a trimer of different particles as opposed to a trimer state of identical atoms, as PhD student Juris Ulmanis explains. They thus showed that Efimov’s theory is applicable to a large number of systems. Project leader Dr. Eva Kuhnle points to another success of the experimental work: “For the first time we were able to not only prove the existence of the trimer ground state, but also the first two excited states. These molecules consisting of three atoms then reach macroscopic sizes, comparable to that of a bacterium.”

Prof. Weidemüller emphasises that these research results are important for many areas of physics – ranging from atomic to nuclear physics: “It is not only the evidence for the universal scaling behaviour that is interesting, but also the accurate measurement of the tiniest deviations of this scaling. From this we gain new knowledge how Efimov’s theory can be applied to realistic three-body systems,” says the Heidelberg scientist. “Our aim is a deeper understanding of quantum mechanical many-body systems, one of the most important but also most difficult research areas in modern physics.”

Original publication:
R. Pires, J. Ulmanis, S. Häfner, M. Repp, A. Arias, E. D. Kuhnle and M. Weidemüller: Observation of Efimov Resonances in a Mixture with Extreme Mass Imbalance. Phys. Rev. Lett. 112, 250404 (published 25 June 2014), doi: 10.1103/PhysRevLett.112.250404

Internet information:
http://www.physi.uni-heidelberg.de/Forschung/QD

Caption:
Schematic representation of Efimov trimers formed from two caesium atoms and one lithium atom. While the trimer’s proportions are microscopic in its ground state, in the second excited state it is nearly a micrometre in size. The size of trimers scales based on a universal scaling law. These trimer states were observed in a mixture of caesium and lithium atoms at temperatures approaching absolute zero. Picture credits: Juris Ulmanis

Contact:
Prof. Dr. Matthias Weidemüller
Institute for Physics
Phone: +49 6221 54-19471
weidemueller@uni-heidelberg.de

Communications and Marketing
Press Office, phone: +49 6221 54-2311
presse@rektorat.uni-heidelberg.de

Marietta Fuhrmann-Koch | idw - Informationsdienst Wissenschaft
Further information:
http://www.uni-heidelberg.de

Further reports about: Efimov Physics Relation energy evidence prediction

More articles from Physics and Astronomy:

nachricht Further Improvement of Qubit Lifetime for Quantum Computers
09.12.2016 | Forschungszentrum Jülich

nachricht Electron highway inside crystal
09.12.2016 | Julius-Maximilians-Universität Würzburg

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: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>