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 Observations of nearby supernova and associated jet cocoon provide new insights on gamma-ray bursts
18.01.2019 | George Washington University

nachricht A new twist on a mesmerizing story
17.01.2019 | ETH Zurich Department of Physics

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: Ten-year anniversary of the Neumayer Station III

The scientific and political community alike stress the importance of German Antarctic research

Joint Press Release from the BMBF and AWI

The Antarctic is a frigid continent south of the Antarctic Circle, where researchers are the only inhabitants. Despite the hostile conditions, here the Alfred...

Im Focus: Ultra ultrasound to transform new tech

World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles

The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.

Im Focus: Flying Optical Cats for Quantum Communication

Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.

In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...

Im Focus: Nanocellulose for novel implants: Ears from the 3D-printer

Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.

It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:

Im Focus: Elucidating the Atomic Mechanism of Superlubricity

The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.

One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Our digital society in 2040

16.01.2019 | Event News

11th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Aachen, 3-4 April 2019

14.01.2019 | Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

 
Latest News

Additive manufacturing reflects fundamental metallurgical principles to create materials

18.01.2019 | Materials Sciences

How molecules teeter in a laser field

18.01.2019 | Life Sciences

The cytoskeleton of neurons has been found to be involved in Alzheimer's disease

18.01.2019 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>