Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Single atoms for detecting extremely weak forces

04.08.2010
MPQ-scientists demonstrate that due to synchronisation atoms can be influenced by forces as weak as 5 yoctonewton.

Back in the 17th century the Dutch physicist Christiaan Huygens made the observation that the oscillation of two pendulums synchronize once they get under mutual influence.

This holds for even very loose coupling, for instance, when both pendulums are mounted onto the same wall. Interestingly, a large variety of oscillating systems shows this kind of behaviour, ranging from organ pipes to lasers or electronic circuits. A team of scientists in the Laser Sepctroscopy Division of Professor Theodor W. Hänsch at the Max Planck Institute of Quantum Optics (MPQ) has now succeeded in observing this technically rather important phenomenon for a single extremely cold atom (Phys. Rev. Lett. 105, 013004, 2 July 2010). As was shown in the experiment, the forces necessary for the synchronisation of the atomic oscillation with an external radiofrequency signal were as low as 5 yoctonewton (5 x 10^-24 N). Hence, single atoms can serve as extremely sensitive detectors for very weak forces – perhaps even sensitive enough for measuring the magnetic moment of a single molecule for the first time.

The experiment starts with storing a single magnesium ion in a so-called Paul-trap. The alternating fields of the trap keep the atom at a fixed point in space, whereas the very high vacuum guarantees that the ion oscillates without perturbation. The ion is then addressed by two well tuned laser beams which make it oscillate with an amplitude of around a tenth of a millimetre. High-resolution optics and a sensitive camera make it possible to register this oscillation by the emitted stray light. In order to investigate the synchronisation of the oscillation of the optically excited atom with an external source a second alternating field is applied to an electrode nearby, and the ion oscillation is monitored with a stroboscope. Once the frequency of the external signal is close enough to the oscillation frequency of the ion its motion sychronizes with the external field.

A careful determination of the forces exerted by the applied ac-field shows that even very small excitations of only 5 yN give rise to synchronisation. Without the experimental “tricks” described above it is almost impossible to detect forces of this order. For example, a force of 5 yN would displace the ion by only around one nanometer (10^-9 metre), whereas the amplitude of the ion oscillation due to its temperature already amounts to 5000 nanometres.

The extremely high sensitivity demonstrated in this experiment offers a variety of applications. For example, it could be used to measure the magnetic field of a single molecule for testing fundamental interactions. The experiment described here is a promising step in this direction. Maximilian Herrmann

Original publication:
S. Knünz, M. Herrmann, V. Batteiger, G. Saathoff, T.W. Hänsch,
K. Vahala, and Th. Udem
Injection locking of a trapped-ion phonon laser
Physical Review Letters 105, 013004 (2010)
Contact:
Prof. Dr. Theodor W. Hänsch
Chair of Experimental Physics at Ludwig-Maximilians-Universität Munich
Director at Max Planck Institute of Quantum Optics
Hans-Kopfermann-Straße 1
85748 Garching
Phone: +49 - 89 / 32905 702/712
Fax: +49 - 89 / 32905 312
E-mail: t.w.haensch@mpq.mpg.de
Dr. Maximilian Herrmann
Max Planck Institute of Quantum Optics
Phone: +49 - 89 / 32905 – 266
Fax: +49 - 89 / 32905 – 312
E-mail: maximilian.herrmann@mpq.mpg.de
Dr. Olivia Meyer-Streng
Press & Public Relations
Max Planck Institute of Quantum Optics
Phone: +49 - 89 / 32905 - 213
e-mail: olivia.meyer-streng@mpq.mpg.de

Dr. Olivia Meyer-Streng | idw
Further information:
http://www.mpq.mpg.de

More articles from Physics and Astronomy:

nachricht Meteoritic stardust unlocks timing of supernova dust formation
19.01.2018 | Carnegie Institution for Science

nachricht Artificial agent designs quantum experiments
19.01.2018 | Universität Innsbruck

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: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | 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

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>