Home | deutsch | Legals | Sitemap | Intranet | KIT
Portrait Monika Landgraf
Contact:
Monika Landgraf
Chief Press Officer

Phone: +49 721 608-47414
Fax: +49 721 608-43658
e-mail

To the pressroom

Press Release 156/2012

Science: Quantum Oscillator Responds to Pressure

Resonance Frequency of Single Atomic Defects Can Be Changed by Mechanical Deformation / Materials for Nanoelectronic Components Can Be Studied Better
Im Diagramm sind Frequenzspektren gegen mechanische Verformung aufgetragen. Jedes atomare Quantensystem hinterlässt eine charakteristische weiße Linie.  (Bild: KIT / CFN)
Frequency spectra are plotted versus mechanical deformation in the diagram. Every atomic quantum system leaves a characteristic white line. (Photo: KIT / CFN)

In the far future, superconducting quantum bits might serve as components of high-performance computers. Today already do they help better understand the structure of solids, as is reported by researchers of Karlsruhe Institute of Technology in the Science magazine. By means of Josephson junctions, they measured the oscillations of individual atoms “tunneling” be-tween two positions. This means that the atoms oscillated quantum mechanically. Deformation of the specimen even changed the frequency (DOI: 10.1126/science.1226487).

“We are now able to directly control the frequencies of individual tunneling atoms in the solid,” say Alexey Ustinov and Georg Weiß, Professors at the Physikalisches Institut of KIT and members of the Center for Functional Nanostructures CFN. Metaphorically speaking, the researchers so far have been confronted with a closed box. From inside, different clattering noises could be heard. Now, it is not only possible to measure the individual objects contained, but also to change their physical properties in a controlled manner.

The specimen used for this purpose consists of a superconducting ring interrupted by a nanometer-thick non-conductor, a so-called Josephson junction. The qubit formed in this way can be switched very precisely between two quantum states. “Interestingly, such a Josephson qubit couples to the other atomic quantum systems in the non-conductor,” explains Ustinov. “And we measure their tunneling frequencies via this coupling.”

At temperatures slightly above absolute zero, most sources of noise in the material are switched off. The only remaining noise is produced by atoms of the material when they jump between two equivalent positions. “These frequency spectra of atom jumps can be measured very precisely with the Josephson junction,” says Ustinov. “Metaphorically speaking, we have a microscope for the quantum mechanics of individual atoms.“

In the experiment performed, 41 jumping atoms were counted and their frequency spectra were measured while the specimen was bent slightly with a piezo element. Georg Weiß explains: “The atomic dis-tances are changed slightly only, while the frequencies of the tunneling atoms change strongly.” So far, only the sum of all tunneling atoms could be measured. The technology to separately switch atomic tunneling systems only emerged a few years ago. The new method developed at KIT to control atomic quantum systems might provide valuable insights into how qubits can be made fit for applica-tion. However, the method is also suited for studying materials of conventional electronic components, such as transistors, and estab-lishing the basis of further miniaturization.

Web sites of the researchers:
http://www.phi.kit.edu/ustinov-research.php
http://www.phi.kit.edu/weiss-atomares_tunneln.php


Click here for the paper in Science:
http://www.sciencemag.org/magazine  

 

Karlsruhe Institute of Technology (KIT) is a public corporation according to the legislation of the state of Baden-Württemberg. It fulfills the mission of a university and the mission of a national research center of the Helmholtz Association. Research activities focus on energy, the natural and built environment as well as on society and technology and cover the whole range extending from fundamental aspects to application. With about 9000 employees, including nearly 6000 staff members in the science and education sector, and 24000 students, KIT is one of the biggest research and education institutions in Europe. Work of KIT is based on the knowledge triangle of research, teaching, and innovation.

kes, 12.10.2012

For further information, please contact:

Kosta Schinarakis
PKM, Themenscout
Tel.: +49 721 608-41956
Fax: +49 721 608-43568
E-Mail:schinarakis@kit.edu
The photo of printing quality may be requested by presseKwd0∂kit edu or phone: +49 721 608-47414. The press release is available as a PDF file.