- Published on 12 October 2010
A group of researchers in Greifswald, Germany, measured the electron concentration and electron temperature in the active discharge zone of a self-organized plasma jet. Self-organized discharge patterns are shown as time averaged top view in the picture.
Miniaturized non-thermal plasma jets are an emerging technique for surface treatments at ambient pressure, such as cleaning, activation, etching, films deposition and more.
The authors of this EPJ D paper used two independent approaches: spectroscopy and a two-dimensional fluid model calculation of a discharge filament. The results from the two methods are consistent and indicate electron concentrations between 2.2 and 3.3×1014 cm-3. This work represents a first step towards a thorough physical description of the discharge dynamics and energy transport to gain a better understanding of self-organization effects in non thermal plasma jets.
- Published on 01 September 2010
The topics of this special issue will include: Quantum simulation using cold atoms in optical lattices; fermionic mixtures of ultracold atoms; collisions of cold polar molecules; controlled interactions in quantum gases of metastable atoms; cavity-mediated molecular cooling; quantum-degenerate dipolar gases of bialkali molecules.
- Published on 19 July 2010
Professor Gaetana Laricchia of UCL, London, has been awarded the Thomson medal and prize for her contributions to the development of the world's only positronium beam and its use to probe the properties of atoms and molecules. This follows closely the Occhialini prize which she received in 2009.
- Published on 17 June 2010
Stark deceleration has emerged over the last decade as a leading technique for obtaining packets of quantum-state-selected molecules whose velocity can be tuned all the way down to zero. Here, a new compact, ultrahigh-vacuum-compatible Stark decelerator is described and demonstrated. The deceleration stages are fashioned out of tantalum wires, reducing the total length to about a tenth of that of a conventional Stark decelerator with the same number of electrode pairs.
The significantly lower cost of assembling and operating the wire decelerator makes it an attractive source of cold molecules, for use in applications ranging from trapping experiments to cold collisions to sympathetic cooling.
A. Marian, H. Haak, P. Geng, and G. Meijer, Eur. Phys. J. D (2010)
- Published on 26 April 2010
Kurt Becker, Associate Provost at the Polytechnic Institute of NYU and Editor in Chief of EPJ D, was awarded the 2010 SASP Erwin Schrödinger Medal. The announcement was made in January 2010 during the Symposium of Atomic, Cluster, and Surface Physics (SASP) held in Obergurgl, Austria. Dr. Becker was cited for his “outstanding scientific achievements and contributions to research in molecular physics – specifically, the interaction of electrons with molecules and clusters – as well as in the properties and applications of plasmas”. The medal is named after the Austrian theoretical physicist Schrödinger, who won the Nobel Prize in 1933 for his work on the development and formulation of quantum mechanics. The entire journal team is delighted for Kurt Becker and congratulates him on this prestigious achievement.
- Published on 19 April 2010
Photodetachment microscopy provides the best electron affinity measurements on atoms and molecules. Photodetachment of a negative ion produces a nearly free electron, hardly perturbed by the residual atomic core. Applying an external electric field does not only concentrate the photoelectron current in a round spot, but also gives rise to an electron interference pattern, due to the existence of a pair of possible trajectories bound to every point of the spot. This very fundamental matter-wave interferometer produces extraordinarily robust interferograms. Although magnetic fields, even in the sub-microT range, causes fluxes between the interfering trajectories that can be huge compared to the quantum unit of magnetic flux, a magnetic perturbation of the system appears to only produce a global deviation of the spot, without any modification of the interference pattern. The main result of the recent paper published in EPJ D by Chaibi et al. is that even in higher magnetic fields (typically 100 microT) the electron interference phase, or number of interference rings, remain unperturbed. This comfirms photodetachment as a highly accurate method for electron spectrometry and electron affinity measurements.
To read the full paper ‘Effect of a magnetic field in photodetachment microscopy’ by W. Chaibi et al., Eur. Phys. J. D (2010) click here
- Published on 14 April 2010
Quantum memories are essential elements for many potential applications of quantum technology. Research on the development of such memories is currently very lively, with a particular emphasis on memories that can interface with photons, which are the best carriers of quantum information over long distances. A Colloquium paper in the May issue on EPJ D reviews a number of different approaches to this challenge, with a focus on the approaches that were represented in the large European Union Integrated Project "Qubit Applications". This Colloquium covers solid-state atomic ensembles, nitrogen-vacancy centres, quantum dots, single atoms and atomic gases. Since the considered approaches are very diverse, an important part of the work was to establish criteria that allow a meaningful comparison. The authors discuss both the current experimental state of the art and the potential long-term performance of the various systems.
To read the full paper ‘Quantum Memories’ by C. Simon et al. click here
- Published on 01 March 2010
Multi-mode optical systems can improve precision measurements in the domain of quantum imaging and metrology. In this context, mastering quantum fluctuations and correlations in complex optical systems is crucial. In a recent EPJ D paper, the authors G. Patera, N. Treps, C. Fabre and G.J. de Valcárcel present the quantum model for an optical parametric oscillator synchronously pumped by a mode locked laser. To cope with the complexity of a system that usually involves about 100 000 modes, the authors introduce new physical objects that they call supermodes, which are proper combinations of standard modes. Their dynamics is studied from both a classical and a quantum point of view with respect to the experimental condition considered. This study shows that a synchronously pumped optical parametric oscillator is a suitable and malleable source of highly multimode non-classical light in the temporal domain.
To read the full paper "Quantum theory of synchronously pumped type I optical parametric oscillators: characterization of the squeezed supermodes" Eur. Phys. J. D 56, 123-140 (2010) click here