Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mysteries and Surprises in Quantum Physics

10.05.2007
“Cavity quantum electrodynamics” is a sub-field of quantum optics. Speaking at the EPL symposium, “Physics In Our Times” held today (9 May) at the Fondation Del Duca de l’Institut de France, Paris Professor Serge Haroche from the Collège de France and the École Normale Supérieure in Paris, explained how he and his colleagues manipulate and control single atoms and single photons interacting in a cavity, which is a box made of highly reflecting walls.

By studying the behaviour of these atoms and photons in this protected environment, the physicists can illustrate fundamental aspects of quantum theory, such as state superpositions, complementarity and decoherence. This research is related to the physics of quantum information, a new domain at the frontier of information science and physics that tries to harness the logic of the quantum world to realise tasks in communication and computing that classical devices cannot achieve.

“During the 20th century, quantum physics has given us new technologies that have changed our lives – for example the computer, the laser and magnetic resonance imaging to name a few,” explained Prof. Haroche. “However, quantum laws have counterintuitive aspects that defy common sense. This has led to a paradox: although we all take advantage of quantum physics, it remains very strange - even some of the scientists that developed the theory, such as Einstein, Schrödinger and de Broglie, were uneasy about its deep meaning,” he said.

Prof. Haroche and his team have recently succeeded in trapping a single photon in a box on the time scale of seconds and have detected this photon many times without destroying it. The researchers have achieved this by sending atoms across the box and measuring the imprint left on the atoms by the photon. This is a new kind of light detection called ‘quantum non-demolition’,” explained Prof. Haroche. “Until now, single photons were always destroyed upon detection.”

The result means that it is now possible repeatedly to extract information from the same photon. This is important because the major part of all information we get from the universe come from light. “Developing a new way of ‘seeing’ could have applications in quantum science,” said Prof. Haroche. “A photon could share its information with an ensemble of atoms to build up an ‘entangled state’ of light or matter”.

Attempting to manipulate and control quantum systems raises important questions about the transition between quantum and classical behaviour. “Fundamentally, the goal is to understand nature better,” explained Prof. Haroche. “Applications, such as quantum communication machines, will certainly come but what they will be useful for is not yet clear. This is why research is so exciting – unpredictable things keep happening all the time.”

Prof. Haroche’s group is currently working with atoms and photons in cavities but related work is being done by other groups on trapped ions and cold atoms in optical potential wells, with superconducting junction or quantum dots in solid state devices. “Although the technologies may differ widely, the quantum and information science concepts used are the same,” he explained. “We are therefore witnessing a kind of unification between different fields of research that is very promising.”

Dianne Stilwell | alfa
Further information:
http://www.iop.org/EJ/journal/EPL

More articles from Physics and Astronomy:

nachricht NASA's James Webb Space Telescope completes final cryogenic testing
21.11.2017 | NASA/Goddard Space Flight Center

nachricht Previous evidence of water on mars now identified as grainflows
21.11.2017 | US Geological Survey

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: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Previous evidence of water on mars now identified as grainflows

21.11.2017 | Physics and Astronomy

NASA's James Webb Space Telescope completes final cryogenic testing

21.11.2017 | Physics and Astronomy

New catalyst controls activation of a carbon-hydrogen bond

21.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>