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EPJ B - sp3 domains in graphite induced by visible light
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- Published on 03 May 2010
Keiichiro Nasu reviews models of photo-induced structural phase transitions in relation to recent experimental results on unconventionally photoactive solids, where the relaxation of optical states results in macroscopic excited domains with new structural and electronic orders. Two key concepts, the hidden multi-stability of the ground state and proliferations of optically excited states are discussed. Taking the ionic to neutral phase transition in an organic charge-transfer crystal as example, the author documents the fundamental nature of photo-induced structural phase transitions. Further, Nasu recounts the details of the discovery of a new photo-induced phase of carbon, named "diaphite", located in between graphite and diamond. The mechanism of this photo-induced structural phase transition is discussed in terms of the proliferation of photo-generated inter-layer charge-transfer excitations in the visible regime.
To read the full paper 'sp3 domain in graphite by visible light and photoinduced phase transitions' by K. Nasu, European Physical Journal B click here.
Schrödinger Medal awarded to EPJ D Editor in Chief
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- 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.
EPJ D - Electrons go unperturbed in a matter-wave interferometer
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- 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
Quantum memories set to go a long way
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- 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
Liquid crystals straighten up
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- Published on 06 April 2010
Grazing incidence X-ray diffraction, performed by Grelet and colleagues, reveals that thin films of discotic liquid crystals typically prefer to lie flat in columns oriented along the surface of their substrate. These materials are potentially useful for organic solar cells, but to achieve good performance from such devices, the column axis should rather be oriented vertical to the conducting substrate. However, the authors of this EPJ E paper have discovered a specific thermal process that makes it possible to change the column alignment from planar to vertical and achieve the best conditions for charge transport in photovoltaic devices.
To read the full paper ‘Morphology of open films of discotic hexagonal columnar liquid crystals as probed by grazing incidence X-ray diffraction’ click here
Giving light a good squeeze
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- 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
Athene Donald wins Glamour award
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- Published on 11 January 2010
Athene Donald, the former editor in chief of EPJ E and current member of its advisory editorial board, has won the Science & Technology Award issued by women’s magazine Glamour.
Daan Frenkel becomes Editor in Chief of EPJ E
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- Published on 05 January 2010
EPJ E welcomes Daan Frenkel as new Editor in Chief, next to Richard Jones and Frank Jülicher. Daan Frenkel is a computational physicist who's research focuses on numerical exploration of routes to design novel, self-assembling structures and materials. Currently he is a professor at the universities of Cambridge, Amsterdam, Utrecht and Beijing. He is a foreign member of the British Royal Society and he has many received prestigious awards such as the Aneesur Rahman Prize of the APS, the Spinoza Prize of the Dutch Research Council and the Berni J. Alder CECAM Prize.
Nigel Mason becomes Editor in Chief of EPJ D
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- Published on 04 January 2010
We are pleased to announce that from January 2010 Nigel Mason, Professor of Physics at the Open University, UK, will be leading EPJ D, together with Kurt Becker and Claude Fabre. Nigel Mason brings to the journal an interdisciplinary approach to the AMOP field. His research covers a wide range of AMOP topics spanning physics and chemistry including astrochemistry, atmospheric science, surface science and spectroscopy. Since the 1990s he has studied the spectroscopy of over 100 molecules (mainly of atmospheric interest) using synchrotron radiation quantifying their photolysis rates and global warming potential. Research on the formation of molecules by irradiation of low temperature (20K) ices has led to a new research programme exploring processes on planetary systems and in the interstellar medium. Most recently his research has extended to study radiation damage processes within biomolecular systems including DNA.
First proton–proton collisions at the LHC as observed with the ALICE detector
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- Published on 14 December 2009
On 23rd November 2009, during the early commissioning of the CERN Large Hadron Collider (LHC), two counter-rotating proton bunches were circulated for the first time concurrently in the machine, at the LHC injection energy of 450 GeV per beam, allowing all LHC experiments to report first collision candidates.
284 such candidates were recorded by the ALICE experiment, allowing the events to be immediately reconstructed and analyzed. The results obtained by measuring the spatial distribution (specifically, the pseudorapidity density) of charged primary particles in the central region, were found to be consistent with previous measurements in proton-antiproton interactions at the same centre-of-mass energy at the CERN SppS collider (UA5 Collaboration, G.J. Alner et al., Z Phys. C 33 (1986), DOI 10.1007/BF01410446).
To read this paper click here
J Schukraft, the ALICE spokesman, said: This important benchmark test illustrates also the excellent functioning and rapid progress of the LHC accelerator, and of both the hardware and software of the ALICE experiment, in this early start-up phase.
The paper is published open access on SpringerLink.com and distributed under the Creative Commons Attribution Noncommercial License.
To read the full paper click here
