Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Two or one splashing? It’s different!

15.01.2015

If two children splash in the sea high water waves will emerge due to constructive superposition. Different observations are made for the microscopic world in an experiment at the University of Bonn, where physicists used a laser beam to generate light waves from two cesium atoms. The light waves were reflected back from two parallel mirrors. It turned out that this experimental arrangement suppressed the emergence of high light waves. With their results, which are published now in the „Physical Review Letters“, the scientists observed the most fundamental scenario of light-matter interaction with two atoms.

The physicists at the University of Bonn confined two levitating cesium atoms in a light cage for photons. A laser beam continuously irradiated the two atoms, which scattered the laser light similar to levitating dust in a sunbeam. The scattered light waves superimpose and were reflected back onto the atoms by two parallel mirrors.


In the lab: Dr. René Reimann, Tobias Macha and Prof. Dr. Dieter Meschede from the Institute of Applied Physics of the University Bonn.

(c) Photo: Volker Lannert/Uni Bonn

“We expected that two atoms in such a cage would behave differently from a single atom” says first author Dr. René Reimann, colleague of Prof. Dr. Dieter Meschede at the “Institut für Angewandte Physik”, University of Bonn. This matches with our everyday experience: Two splashing children in the sea produce different water waves than a single child. However, for the light cage with the light waves emitted from the two atoms the analogy to the splashing children in the sea does not fully hold. Here no high light waves are observed.

Backaction suppresses high light waves

The surprising situation of the two atoms inside the light cage can be illustrated with two children in a swimming pool instead of the sea. Here the children create water waves that are partially reflected from the pool edge. Now the reflected waves and the forward running waves cancel each other. “Due to this feedback two children can in the best case generate barely higher waves than a single child”. Albeit by changing the distance between them, the kids in the pool can change the height of the water waves.
Keeping this in mind one can understand the situation of the two cesium atoms in the experiment: Even in the best case when the light waves of the two atoms constructively interfere barely more photons could be counted compared to the one atom case. “It became clear that the mirrors introduce a strong backaction that hinders the emergence of high light waves”, describes Dieter Meschede.

New insights in light-matter interaction

Nevertheless minimal position changes of the levitating cesium atoms in the light cage can be detected through distinct changes in the height of the superimposed light waves. “Up to now this was not possible. Now, this opens up new insights and experimental possibilities for the light-atom interaction of two-atom systems”, says René Reimann. These new possibilities could support forward-looking technologies like quantum memories and quantum networks for telecommunication and computation.

So far, international teams of scientists observed the interaction of a single or many atoms with photons in a light cage. For his fundamental contributions to this research, Serge Haroche was awarded the Nobel Prize in physics in 2012. Now, the physicists from Bonn achieved to observe the interaction of exactly two atoms in a light cage. “With this experiment the most fundamental case of collective light-matter interaction has been realized”, says Dieter Meschede.

The research group “Quantum Technologies” at the University of Bonn experimentally investigates the controlled interaction between atoms and light. The group is focusing on the generation of particular quantum mechanical states.

Publication: R. Reimann, W. Alt, T. Kampschulte, T. Macha, L. Ratschbacher, N. Thau, S. Yoon, D. Meschede, Cavity-Modified Collective Rayleigh Scattering of Two Atoms, Physical Review Letters, DOI: 10.1103/PhysRevLett.114.023601

Contact information for media:

Dr. René Reimann
Institut für Angewandte Physik
Forschungsgruppe Quantentechnologie
Tel. 0228/733489
E-Mail: reimann@iap.uni-bonn.de

Prof. Dr. Dieter Meschede
Institut für Angewandte Physik
Forschungsgruppe Quantentechnologie
Tel. 0228/733477
E-Mail: meschede@uni-bonn.de

Johannes Seiler | idw - Informationsdienst Wissenschaft
Further information:
http://www.uni-bonn.de/

More articles from Physics and Astronomy:

nachricht Water without windows: Capturing water vapor inside an electron microscope
13.12.2017 | Okinawa Institute of Science and Technology (OIST) Graduate University

nachricht Columbia engineers create artificial graphene in a nanofabricated semiconductor structure
13.12.2017 | Columbia University School of Engineering and Applied Science

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: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Protein Structure Could Unlock New Treatments for Cystic Fibrosis

14.12.2017 | Life Sciences

Cardiolinc™: an NPO to personalize treatment for cardiovascular disease patients

14.12.2017 | Life Sciences

ASU scientists develop new, rapid pipeline for antimicrobials

14.12.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>