Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Timely discovery: Physics research sheds new light on quantum dynamics

16.05.2012
Kansas State University physicists and an international team of collaborators have made a breakthrough that improves understanding of matter-light interactions.

Their research allows double ionization events to be observed at the time scale of attoseconds, which are one-billionth of a billionth of a second. The physicists have also shown that these ionization events occur earlier than thought -- a key factor to improving knowledge of correlated electron dynamics, which involve two electrons and their interactions with each other. The work appears in a recent issue of Nature Communications.

"The research involves studying if these correlated electrons, ejected from an atom or a molecule, are traveling in the same or opposite directions," said Nora Johnson, a doctoral student in physics from Dell Rapids, S.D. "We can also determine if one electron has all the energy or if they share energy equally."

Other university researchers involved include Itzik Ben-Itzhak, university distinguished professor of physics, and Matthias Kling, assistant professor of physics. Kling is the principal investigator for the project and is on research leave at the Max Planck Institute of Quantum Optics in Garching, Germany, where he is performing related research. All of the researchers are involved with the university's James R. Macdonald Laboratory.

Double ionization occurs when two electrons are removed from an atom -- a process that can be caused by an intense laser pulse. When double ionization occurs in the laser field it can take the form of a sequential process, in which the laser removes one electron and then removes the other electron. This project focuses on another mechanism -- the nonsequential process for ionization -- in which the laser removes one electron, which is accelerated and hits a second electron to excite it. The laser then knocks out the second electron from the atom.

The researchers sent a four femtosecond-long laser pulse onto argon atoms. A femtosecond is a millionth of a billionth of a second. While most of the argon atoms were singly ionized, approximately every thousandth atom underwent nonsequential double ionization.

"The surprising result is that everybody expected that the second electron becomes excited and then, when the laser field is the strongest, this electron is removed," said Ben-Itzhak, director of the Macdonald laboratory. "But it actually happens earlier."

The researchers discovered that the time between the recollision and the second ionization is about 400 attoseconds. This is about 200 attoseconds earlier than the peak of the field, which is when physicists expected the second ionization to occur.

Johnson conducted her early experiments at the Macdonald Laboratory. She performed more extensive experiments during a 2009 Fulbright Fellowship at the Max Planck Institute of Quantum Optics. The two organizations have an ongoing collaboration and the Kansas State University team is directly funded by a $400,000 National Science Foundation grant.

"The key is that Nora has brought knowledge from Germany about short pulses and we can now continue these experiments in Kansas," Ben-Itzhak said. "We have an ongoing collaboration with them that goes both ways."

Now that the researchers have made an important discovery with atoms, Johnson is performing a similar experiment with molecules. She is performing experiments at the Macdonald Laboratory and will use the laboratory's expertise in imaging molecules.

"A molecule is more complex than an atom, which typically means its reaction dynamics are richer," Johnson said. "We are excited to pursue correlated electron dynamics at the next level of complexity to further understand them."

Itzik Ben-Itzhak | EurekAlert!
Further information:
http://www.k-state.edu
http://www.k-state.edu/media/newsreleases/may12/attosecond51512.html

More articles from Physics and Astronomy:

nachricht Molecule flash mob
19.01.2017 | Technische Universität Wien

nachricht Magnetic moment of a single antiproton determined with greatest precision ever
19.01.2017 | Johannes Gutenberg-Universität Mainz

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: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland

19.01.2017 | Earth Sciences

Not of Divided Mind

19.01.2017 | Life Sciences

Molecule flash mob

19.01.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>