News / Highlights / Colloquium
- Published on 15 May 2013
Physicists are providing an all-in-one guide to help calculate the effect the use of optical tweezers has on the energy levels of atoms under study
A small piece of paper sticks to an electrically charged plastic ruler. The principle of this simple classroom physics experiment is applied at the microscopic scale by so-called optical tweezers to get the likes of polystyrene micro-beads and even living cells to “stick” to a laser beam, or to trap atoms at ultra-low temperatures. Physicist Fam Le Kien and his colleagues from the Institute of Atomic and Subatomic Physics of the Vienna University of Technology, Austria, provide a comprehensive manual with general theoretical tools, definitions, and spectroscopic data sets for calculating the energy levels of atoms, which are modified by light emanating from optical tweezers, in a study just published in EPJ D.
- Published on 27 March 2013
New research shows that the speed of light may not be fixed after all, but rather fluctuates
Two EPJ D papers challenge established wisdom about the nature of vacuum. In one paper, Marcel Urban from the University of Paris-Sud, located in Orsay, France and his colleagues identified a quantum level mechanism for interpreting vacuum as being filled with pairs of virtual particles with fluctuating energy values. As a result, the inherent characteristics of vacuum, like the speed of light, may not be a constant after all, but fluctuate. Meanwhile, in another study, Gerd Leuchs and Luis L. Sánchez-Soto, from the Max Planck Institute for the Physics of Light in Erlangen, Germany, suggest that physical constants, such as the speed of light and the so-called impedance of free space, are indications of the total number of elementary particles in nature.
- Published on 17 March 2013
The unexpected diversity of metallic nanoclusters’ inner structure has now been catalogued into families
Physicists have gained new insights into the inner intricacies of the structural variations of metallic nanoclusters. This work by Luca Pavan, Cono Di Paola and Francesca Baletto from King's College London, UK, has just been published in EPJ D. It takes us one step closer to tailoring on-demand characteristics of metallic nanoparticles. Indeed, the geometric structure of these nanoclusters influences their chemical and physical properties, which differ from those of individual molecules and of bulk metals.
- Published on 04 February 2013
From January 2013 Vladimir Bužek succeeds Claude Fabre as Editor in Chief of EPJ D with responsibility for papers in quantum optics, quantum information and related topics.
Prof. Dr. Bužek graduated from the Moscow State University (both MSc and PhD) in theoretical physics. His research interests are focused on quantum optics, quantum information sciences, quantum measurement theory and foundations of quantum mechanics. He has been the head of the Research Center for Quantum Information at the Slovak Academy of Sciences and holds a professorial position at the Faculty of Informatics of the Masaryk University in Brno, Czech Republic.
- Published on 15 January 2013
Understanding the mechanisms of electron-molecule collisions could help predict the operations inside the fusion chamber of the ITER reactor
An international team of physicists has calculated the efficiency of a reaction involving an incoming electron kicking out an electron from the metal beryllium (Be) or its hydrogen compound molecules, in an article just published in EPJ D. The efficiency, which partly depends on the electron’s incoming speed, is encapsulated in a quantity referred to as electron-impact ionisation cross sections (EICS). Electron-molecule interactions matter because they occur in a broad range of applications from the simplest like fluorescent lamps to the most complex, for example, in ionised matter found in plasmas such as latest generation screens, the outer space of the universe, and in fusion reactors.
- Published on 10 January 2013
New models suggest devising means of probing a surface at a sub-micrometric level as this will help us understand how electrons’ diffusion affects long-range attractive forces
Theoretical physicist Elad Eizner from Ben Gurion University, Israel, and colleagues created models to study the attractive forces affecting atoms located at a wide range of distances from a surface, in the hundreds of nanometers range. Their results, just published in EPJ D, show that these forces depend on electron diffusion, regardless of whether the surface is conducting or not. Ultimately, these findings could contribute to designing minimally invasive surface probes.
- Published on 26 November 2012
Atomic and molecular collisions occurring at low impact energies and for neutral targets need adequate methods for accurately measuring their scattering properties. Such measures are fundamental to the description of the dynamics of plasmas and provide insight into the long-range Coulomb interactions between charged particles. In the last twenty years many novel non-perturbative approaches have been applied. The time-dependent close-coupling (TDCC) approach, discussed in this EPJD Review, differs fundamentally from previous non-perturbative approaches in that it solves the time-dependent, rather than time-independent, Schr¨odinger equation. This Review provides a detailed description of the application of the time-dependent close-coupling approach to ionising collisions of electrons, photons and ions with small atoms and molecules.
- Published on 13 November 2012
Significant progress made in evaluating the density of active species used in medical applications of plasma physics could improve the accuracy of treatment
An international team of scientists working at the Plasma Technology research unit at Ghent University, Belgium, has determined for the first time the absolute density of active substances called radicals found in a state of matter known as plasma, in a study just published in EPJ D. These findings could have important implications for medicine—for example, for stimulating tissue regeneration, or to induce a targeted antiseptic effect in vivo without affecting neighbouring tissues.
- Published on 21 October 2012
Study looks at ways to improve the quality of matter akin to that found in plasma screens by dissolving its self-organised hexagonal filament structures made of electric discharge.
A new study improves our understanding of plasma sources, a state of matter similar to gas in which a certain portion of the particles are ionised and which are used for example in plasma display panels. These results revealed by physicists from the University of Greifswald, Germany, Robert Wild and Lars Stollenwerk, and are about to be published in EPJD.
- Published on 21 October 2012
A trade-off between photon source settings and detector specific requirements allows the generation of high-fidelity single photons.Many quantum technologies—such as cryptography, quantum computing and quantum networks—hinge on the use of single photons. While she was at the Kastler Brossel Laboratory (affiliated with the Pierre and Marie Curie University, École Normale Supérieure and CNRS) in Paris, France, Virginia d’Auria and her colleagues identified the extent to which photon detector characteristics shape the preparation of a photon source designed to reliably generate single photons. In a paper just published