Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Collision of individual atoms leads to twofold change of angular momentum

23.01.2019

Thanks to new technology, it is possible to retain individual atoms, move them in a targeted manner or change their condition. Kaiserslautern physicists also work with this system. In a recent study, they investigated the consequences of the collision of two atoms in a weak magnetic field at low temperature. For the first time they have discovered that atoms, carrying their angular momentum in individual packets (quanta), thereby exchange two packets. It was also shown that the interaction strength between the atoms can be controlled. This is of interest for investigating chemical reactions, for example. The paper was published in the journal Physical Review Letters.

Until a few decades ago it was unthinkable for physicists to carry out experiments with individual atomic particles. Erwin Schrödinger, one of the pioneers of modern quantum theory, expected “ridiculous consequences” from this idea and described it as similarly probable to raising an Ichtyosaurus dinosaur in a zoo.


Professor Artur Widera (right) and Felix Schmidt

Credit: Koziel/TUK

However, advances in laser technology and atomic physics today make experiments with individual atoms possible.

Physicists around Professor Artur Widera and his doctoral student Felix Schmidt at Technische Universität Kaiserslautern (TUK) are also working on this topic in the Individual Quantum Systems research group. They rely on a so-called Bose-Einstein condensate consisting of rubidium atoms.

“In physics, this refers to a state of matter that is comparable with liquid and gaseous states. However, such a condensate is a perfect quantum mechanical state that behaves like a wave,” says Professor Widera. The condensate is comparable to a gas consisting of very few atoms.

In a recent study, together with Professor Eberhard Tiemann of the Gottfried Wilhelm Leibniz University of Hanover, they investigated the effects of a single caesium atom hitting a rubidium atom. To observe the particles, the researchers must first cool them to temperatures just above absolute zero.

“We then used optical tweezers to bring the atoms into contact with each other,” says Felix Schmidt. During this process, atoms are retained using laser beams. The researchers have now added a single caesium atom to the rubidium gas to measure what happens before and after the collision of the atoms.

The physicists observed how the particles change their angular momentum during the impact by measuring the state of the individual caesium atom before and after the collision. In atoms, the angular momentum of the particles is to a certain extent present in individual packages – so-called elementary quanta.

The researchers have now observed that atoms can exchange two such angular momentum quanta at the same time in a single impact. So far, only the exchange of a single package (quants) has been observed. “This is only possible because we conducted the experiment in a low magnetic field,” says Schmidt.

Thus, the energy of the atoms is so low that especially the interaction between the individual elements determines the result of the impact. “This makes it possible for two so-called elementary quanta to be transmitted simultaneously, for example for the angular momentum to change twice,” continues the physicist.

But the scientists also observed another effect. “The weak magnetic field and the low kinetic energy result in the atoms interacting with each other a thousand times larger than the atoms themselves, even at a distance,” Schmidt continues.

By changing the strength of the magnetic field, this effect could also be controlled. The effect is directly related to a very large and very weakly bound molecular state between the two particles. “We were able to indirectly observe a huge molecule about two micrometres in size,” said Schmidt.

This knowledge of interaction between particles at very low energies can, for example, help to investigate bonds in molecules. They consist of at least two atoms which are connected by interactions. This would enable, among other things, the preparation and investigation of very large molecules.

The study was published in the renowned journal Physical Review Letters: “Tailored single-atom collisions at ultra-low energies.”
DOI: 10.1103/PhysRevLett.122.013401
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.122.013401

Wissenschaftliche Ansprechpartner:

Prof. Dr Artur Widera
Department for Individual Quantum Systems
E-mail: widera(at)physik.uni-kl.de
Phone: +49(0)631 205-4130

Felix Schmidt
E-Mail: schmidtf(at)physik.uni-kl.de
Phone: +49(0)631 205-5272

Originalpublikation:

The study was published in the renowned journal Physical Review Letters: “Tailored single-atom collisions at ultra-low energies.”
DOI: 10.1103/PhysRevLett.122.013401
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.122.013401

Melanie Löw | Technische Universität Kaiserslautern
Further information:
http://www.uni-kl.de

More articles from Physics and Astronomy:

nachricht A new stable form of plutonium discovered at the ESRF
21.10.2019 | European Synchrotron Radiation Facility

nachricht Double layer of graphene helps to control spin currents
18.10.2019 | University of Groningen

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: Solving the mystery of quantum light in thin layers

A very special kind of light is emitted by tungsten diselenide layers. The reason for this has been unclear. Now an explanation has been found at TU Wien (Vienna)

It is an exotic phenomenon that nobody was able to explain for years: when energy is supplied to a thin layer of the material tungsten diselenide, it begins to...

Im Focus: An ultrafast glimpse of the photochemistry of the atmosphere

Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich have explored the initial consequences of the interaction of light with molecules on the surface of nanoscopic aerosols.

The nanocosmos is constantly in motion. All natural processes are ultimately determined by the interplay between radiation and matter. Light strikes particles...

Im Focus: Shaping nanoparticles for improved quantum information technology

Particles that are mere nanometers in size are at the forefront of scientific research today. They come in many different shapes: rods, spheres, cubes, vesicles, S-shaped worms and even donut-like rings. What makes them worthy of scientific study is that, being so tiny, they exhibit quantum mechanical properties not possible with larger objects.

Researchers at the Center for Nanoscale Materials (CNM), a U.S. Department of Energy (DOE) Office of Science User Facility located at DOE's Argonne National...

Im Focus: Novel Material for Shipbuilding

A new research project at the TH Mittelhessen focusses on the development of a novel light weight design concept for leisure boats and yachts. Professor Stephan Marzi from the THM Institute of Mechanics and Materials collaborates with Krake Catamarane, which is a shipyard located in Apolda, Thuringia.

The project is set up in an international cooperation with Professor Anders Biel from Karlstad University in Sweden and the Swedish company Lamera from...

Im Focus: Controlling superconducting regions within an exotic metal

Superconductivity has fascinated scientists for many years since it offers the potential to revolutionize current technologies. Materials only become superconductors - meaning that electrons can travel in them with no resistance - at very low temperatures. These days, this unique zero resistance superconductivity is commonly found in a number of technologies, such as magnetic resonance imaging (MRI).

Future technologies, however, will harness the total synchrony of electronic behavior in superconductors - a property called the phase. There is currently a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Symposium on Functional Materials for Electrolysis, Fuel Cells and Metal-Air Batteries

02.10.2019 | Event News

NEXUS 2020: Relationships Between Architecture and Mathematics

02.10.2019 | Event News

Optical Technologies: International Symposium „Future Optics“ in Hannover

19.09.2019 | Event News

 
Latest News

Phagocytes versus killer cells - A closer look into the tumour tissue

21.10.2019 | Life Sciences

A new stable form of plutonium discovered at the ESRF

21.10.2019 | Physics and Astronomy

Candidate Ebola vaccine still effective when highly diluted, macaque study finds

21.10.2019 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>