Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Milestone on a nanometre level

28.06.2010
Physicists succeed in characterizing the quantum state of a complex system

Physicists from Marburg and the US have succeeded in characterizing the quantum state of a system consisting of millions of particles by bringing experimental data and theoretical predictions into agreement.

The team of researchers headed by Professors Dr. Stephan Koch und Dr. Mackillo Kira from Philipps-Universität published their results in the renowned journal “Physical Review Letters”.

Modern semiconductor devices, chemical reactions and even biological behaviour are based on nanoscale processes with one nanometre being equal to one millionth of a millimetre. Processes on this scale operate according to the intricate principles of quantum mechanics which are in general highly complex and often unintuitive. In order to design and control such nanosystems, one has to understand the entire underlying quantum mechanic state.

“This objective is currently unreachable for any system larger than a few atoms or ions for the simple reason that the direct measurement of the quantum state would immediately exhaust all resources known to mankind concerning data acquisition, storing, and processing.” explained co-author Koch.

The scientists elegantly avoided this problem by optically exciting the electrons of thin semiconductor quantum wells. Instead of probing the quantum state directly, they carried out high precision measurements to detect subtle changes in the optical quantum-well absorption. Applying cutting-edge many-body theory, they performed rigorous comparisons of the experimental data and the theoretical predictions. „Our detailed comparison between quantitative experiment and theory showed that the absorption behaviour strongly depends on the many-body configuration.” remarked Kira. Thus, it was possible to identify the quantum states of the optically active electrons with a so far unprecedented accuracy.

“This result represents a first milestone towards the characterization of nanoscale processes in semiconductors,” commented Koch, and Kira added that one of the next steps would be to try to control the quantum state of large systems. This could potentially be performed in semiconductors by a detailed control of the quantum aspects of the optical excitation. This project will again be undertaken in cooperation with experimental physicists from the National Institute of Standards and Technology and the University of Colorado in den USA (JILA/NIST).

Original publication: R. P. Smith & al: „Extraction of Many-Body Configurations from Nonlinear Absorption in Semiconductor Quantum Wells”, Physical Review Letters 104 (2010), 247401, doi: 10.1103/PhysRevLett.104.247401

Further Information:
Corresponding author: Professor Dr. Stephan Koch,
Theoretical Semiconductor Physics Group
Tel.: +49 (0) 6421 28-21336
E-Mail: stephan.w.koch@physik.uni-marburg.de

Dr. Susanne Igler | idw
Further information:
http://www.uni-marburg.de

More articles from Physics and Astronomy:

nachricht NASA mission surfs through waves in space to understand space weather
25.07.2017 | NASA/Goddard Space Flight Center

nachricht A new level of magnetic saturation
25.07.2017 | Georg-August-Universität Göttingen

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: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA mission surfs through waves in space to understand space weather

25.07.2017 | Physics and Astronomy

Strength of tectonic plates may explain shape of the Tibetan Plateau, study finds

25.07.2017 | Earth Sciences

The dense vessel network regulates formation of thrombocytes in the bone marrow

25.07.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>