The team of Francesca Ferlaino, University of Innsbruck, discovered that even simple systems, such as neutral atoms, can possess chaotic behavior, which can be revealed using the tools of quantum mechanics. The ground-breaking research, published in the journal Nature, opens up new avenues to observe the interaction between quantum particles.
The team of Francesca Ferlaino, Institute for Experimental Physics of the University of Innsbruck, Austria, has experimentally shown chaotic behavior of particles in a quantum gas.
“For the first time we have been able to observe quantum chaos in the scattering behavior of ultracold atoms,” says an excited Ferlaino. The physicists used random matrix theory to confirm their results, thus asserting the universal character of this statistical theory.
Nobel laureate Eugene Wigner formulated random matrix theory to describe complex systems in the 1950s. Although interactions between neutrons with atomic nuclei were not well-known then, Wigner was able to reliably predict properties of complex spectra by using random matrices.
Today random matrix theory is applied broadly not only in physics but also in number theory, wireless information technology and risk management models in finance to name only a few fields of application. In the Bohigas-Giannoni-Schmit conjecture random matrix theory has been connected to chaotic behavior in quantum mechanical systems.
Catalan physicist Oriol Bohigas, who passed away last year, can be considered the father of quantum chaos research.
Chaos in the quantum world
To observe quantum chaos, the physicists in Innsbruck cool erbium atoms to a few hundred nanokelvin and load them in an optical dipole trap composed of laser beams. They then influence the scattering behavior of the particles by using a magnetic field.
After holding the atoms in the trap for 400 milliseconds, the researchers record the atom number remaining in the trap. Thus, the scientists are able to determine at which magnetic field two atoms are coupled to form a weakly-bound molecule.
At this magnetic field, so-called Fano-Feshbach resonances emerge. After varying the magnetic field in each experimental cycle and repeating the experiment 14,000 times, the physicists identified 200 resonances.
“We were fascinated by how many resonances of this type we found. This is unprecedented in the physics of ultracold quantum gases,” says Francesca Ferlaino’s team member Albert Frisch. To explain the high density of resonances, the researchers used statistical methods. By using Wigner‘s random matrix theory the scientists are able to show that different molecular levels are coupled. This has also been confirmed by computer simulations conducted by Svetlana Kotochigova’s research group at Temple University in Philadelphia, Pennsylvania, USA.
“The particular properties of erbium cause a highly complex coupling behavior between the particles, which can be described as chaotic,” explains Ferlaino. Erbium is relatively heavy and highly magnetic, which leads to anisotropic interaction between atoms. “The electron shell of these atoms do not resemble spherical shells but are highly deformed,” explains Albert Frisch.
“Therefore, the type of interaction between two erbium atoms is significantly different from other quantum gases that have been investigated so far.”
Studying chaos experimentally
In contrast to everyday speech, chaos does not mean disorder for the physicists but rather a well-ordered system that, due to its complexity, shows random behavior. Ferlaino is excited about their breakthrough:
“We have created an experiment that provides a controlled environment to study chaotic processes. We cannot characterize the behavior of single atoms in our experiment. However, by using statistical methods, we can describe the behavior of all particles.”
She compares the method with sociology, which studies the behavior of a bigger community of people, whereas psychology describes the relations between individuals. This work also provides new inroads to the investigation of ultracold gases and, thus, ultracold chemistry.” Ferlaino is convinced: “Our work represents a turning point in the world of ultracold gases.”
The experiment and statistical analysis were carried out at the Institute for Experimental Physics at the University of Innsbruck. Theoretical support was provided by John L. Bohn from the Joint Institute for Laboratory Astrophysics in Boulder, Colorado, USA and the team of Svetlana Kotochigova at Temple University in Philadelphia, Pennsylvania, USA. The Austrian researchers are supported by the Austrian Science Fund FWF and the European Research Council (ERC).
Publication: Quantum Chaos in Ultracold Collisions of Erbium. Frisch A, Mark M, Aikawa K, and Ferlaino F, Bohn JL, Makrides C, Petrov A, and Kotochigova S. Nature 2014
DOI: 10.1038/nature13137 [arXiv:1312.1972v1, http://arxiv.org/abs/1312.1972v1]
Univ.-Prof. Dr. Francesca Ferlaino
Institute for Experimental Physics
University of Innsbruck
Phone: +43 512 507 52440
Dr. Christian Flatz
University of Innsbruck
Phone: +43 512 507 32022
Dr. Christian Flatz | Universität Innsbruck
Nanotechnology for energy materials: Electrodes like leaf veins
27.09.2016 | Helmholtz-Zentrum Berlin für Materialien und Energie GmbH
First quantum photonic circuit with electrically driven light source
27.09.2016 | Westfälische Wilhelms-Universität Münster
Optical quantum computers can revolutionize computer technology. A team of researchers led by scientists from Münster University and KIT now succeeded in putting a quantum optical experimental set-up onto a chip. In doing so, they have met one of the requirements for making it possible to use photonic circuits for optical quantum computers.
Optical quantum computers are what people are pinning their hopes on for tomorrow’s computer technology – whether for tap-proof data encryption, ultrafast...
The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.
“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...
With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.
Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...
For the first time, Fraunhofer IKTS shows additively manufactured hardmetal tools at WorldPM 2016 in Hamburg. Mechanical, chemical as well as a high heat resistance and extreme hardness are required from tools that are used in mechanical and automotive engineering or in plastics and building materials industry. Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden managed the production of complex hardmetal tools via 3D printing in a quality that are in no way inferior to conventionally produced high-performance tools.
Fraunhofer IKTS counts decades of proven expertise in the development of hardmetals. To date, reliable cutting, drilling, pressing and stamping tools made of...
At AKL’16, the International Laser Technology Congress held in May this year, interest in the topic of process control was greater than expected. Appropriately, the event was also used to launch the Industry Working Group for Process Control in Laser Material Processing. The group provides a forum for representatives from industry and research to initiate pre-competitive projects and discuss issues such as standards, potential cost savings and feasibility.
In the age of industry 4.0, laser technology is firmly established within manufacturing. A wide variety of laser techniques – from USP ablation and additive...
27.09.2016 | Event News
23.09.2016 | Event News
20.09.2016 | Event News
27.09.2016 | Life Sciences
27.09.2016 | Physics and Astronomy
27.09.2016 | Life Sciences