Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Quantum Simulation: A Better Understanding of Magnetism

20.11.2015

Heidelberg physicists use ultracold atoms to imitate the behaviour of electrons in a solid

Researchers at Heidelberg University have devised a new way to study the phenomenon of magnetism. Using ultracold atoms at near absolute zero, they prepared a model that simulates the behaviour of electrons in a solid, which enables the investigation of magnetic properties.


Atoms (shown in green and blue) are held in a trap of laser light (red) in which they can move in one dimension only. The atoms can point either up (green) or down (blue), similar to a needle in a compass. When the atoms do not interact, they can move freely in the trap (top picture); they have no discernible order. When repulsive interactions between the atoms are strong (bottom picture), they arrange themselves in the trap, with each atom pointing in the opposite direction of its neighbour.

The findings of the team led by Prof. Selim Jochim of the Institute for Physics are expected to contribute to a better understanding of the fundamental processes in solids and lead to the development of new types of materials over the long term. The results of their quantum simulation research, conducted with physicists from Hannover and Lund (Sweden), appeared in the journal “Physical Review Letters”.

Magnetism has been known for over 2,000 years, and was used early on to develop the compass, whose needles align themselves with the earth's magnetic field. Nonetheless, the microscopic causes of magnetism were not understood until the development of quantum mechanics at the beginning of the 20th century.

One of the most important discoveries was that electrons in a solid behave like tiny compass needles that align themselves with an external magnetic field and also affect each other. The magnetic properties of a solid depend on how adjacent electrons arrange themselves relative to one another. For instance in ferromagnetic substances such as iron, all electrons point in the same direction. In antiferromagnetism, however, each electron points in the opposite direction of its neighbour.

The Heidelberg physicists used very few atoms, namely four, for their quantum simulation. “Precisely preparing such a small number of atoms is a major technical undertaking. It allows us, however, to control the state of the atoms with extreme precision,” explains Simon Murmann, Prof. Jochim’s doctoral student in charge of the experiments who has just completed his thesis on the subject.

The atoms are held in a laser light trap that allows movement in only one dimension. They are subject to virtually the same physical laws as electrons in a solid, but the physicists are able to precisely control the interactions of the atoms. “Initially, there is no interaction between the atoms. In this state, they can move freely inside the trap without any fixed arrangement. But when we introduce increasing repulsion between the atoms, they can no longer pass one another and end up forming a chain. Each atom in the chain points in the opposite direction of its neighbour, one up and one down. This brings about an antiferromagnetic state,” explains the Heidelberg scientist.

This observation is of great interest to the researchers because antiferromagnetism is connected to physical phenomenon that could lead to far-reaching applications. “Superconductivity, i.e. the lossless conduction of electricity, was observed in antiferromagnetic materials at relatively high temperatures of only minus 135 degrees Celsius,” continues Selim Jochim. “We hope that our experiments will contribute to the understanding of the fundamental processes in solids. One vision is to develop new materials that will remain superconductive even at room temperature”.

For their article published in the “Physical Review Letters”, the authors received the coveted “Editors’ Suggestion” distinction.

Original publication:
S. Murmann, F. Deuretzbacher, G. Zürn, J. Bjerlin, S. M. Reimann, L. Santos, T. Lompe, S. Jochim: Antiferromagnetic Heisenberg Spin Chain of a Few Cold Atoms in a One-Dimensional Trap. Physical Review Letters (published online on 19 November 2015), doi: 10.1103/PhysRevLett.115.215301

Contact:
Prof. Dr. Selim Jochim
Center for Quantum Dynamics
Institute for Physics
Phone +49 6221 54-19472

jochim@uni-heidelberg.de

Kommunikation und Marketing
Pressestelle
Tel. +49 6221 54-2311
presse@rektorat.uni-heidelberg.de

Weitere Informationen:

Group of Prof. Dr. Selim Jochim – http://ultracold.physi.uni-heidelberg.de

Marietta Fuhrmann-Koch | idw - Informationsdienst Wissenschaft

More articles from Physics and Astronomy:

nachricht Heat flow through single molecules detected
19.07.2019 | Okinawa Institute of Science and Technology (OIST) Graduate University

nachricht Better thermal conductivity by adjusting the arrangement of atoms
19.07.2019 | Universität Basel

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: Better thermal conductivity by adjusting the arrangement of atoms

Adjusting the thermal conductivity of materials is one of the challenges nanoscience is currently facing. Together with colleagues from the Netherlands and Spain, researchers from the University of Basel have shown that the atomic vibrations that determine heat generation in nanowires can be controlled through the arrangement of atoms alone. The scientists will publish the results shortly in the journal Nano Letters.

In the electronics and computer industry, components are becoming ever smaller and more powerful. However, there are problems with the heat generation. It is...

Im Focus: First-ever visualizations of electrical gating effects on electronic structure

Scientists have visualised the electronic structure in a microelectronic device for the first time, opening up opportunities for finely-tuned high performance electronic devices.

Physicists from the University of Warwick and the University of Washington have developed a technique to measure the energy and momentum of electrons in...

Im Focus: Megakaryocytes act as „bouncers“ restraining cell migration in the bone marrow

Scientists at the University Würzburg and University Hospital of Würzburg found that megakaryocytes act as “bouncers” and thus modulate bone marrow niche properties and cell migration dynamics. The study was published in July in the Journal “Haematologica”.

Hematopoiesis is the process of forming blood cells, which occurs predominantly in the bone marrow. The bone marrow produces all types of blood cells: red...

Im Focus: Artificial neural network resolves puzzles from condensed matter physics: Which is the perfect quantum theory?

For some phenomena in quantum many-body physics several competing theories exist. But which of them describes a quantum phenomenon best? A team of researchers from the Technical University of Munich (TUM) and Harvard University in the United States has now successfully deployed artificial neural networks for image analysis of quantum systems.

Is that a dog or a cat? Such a classification is a prime example of machine learning: artificial neural networks can be trained to analyze images by looking...

Im Focus: Extremely hard yet metallically conductive: Bayreuth researchers develop novel material with high-tech prospects

An international research group led by scientists from the University of Bayreuth has produced a previously unknown material: Rhenium nitride pernitride. Thanks to combining properties that were previously considered incompatible, it looks set to become highly attractive for technological applications. Indeed, it is a super-hard metallic conductor that can withstand extremely high pressures like a diamond. A process now developed in Bayreuth opens up the possibility of producing rhenium nitride pernitride and other technologically interesting materials in sufficiently large quantity for their properties characterisation. The new findings are presented in "Nature Communications".

The possibility of finding a compound that was metallically conductive, super-hard, and ultra-incompressible was long considered unlikely in science. It was...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on UV LED Technologies & Applications – ICULTA 2020 | Call for Abstracts

24.06.2019 | Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

 
Latest News

Heat flow through single molecules detected

19.07.2019 | Physics and Astronomy

Heat transport through single molecules

19.07.2019 | Physics and Astronomy

Welcome Committee for Comets

19.07.2019 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>