News

January 2012

EPJ C - "Spooky action at distance" in particle physics?!

Physicists have developed the first conclusive test to better understand high-energy particles correlations.

Researchers have devised a proposal for the first conclusive experimental test of a phenomenon known as "Bell’s nonlocality". This test is designed to reveal correlations that are stronger than any classical correlations, and do so between high-energy particles that do not consist of ordinary matter and light. These results are relevant to the so-called "CP violation" principle, which is used to explain the dominance of matter over antimatter. These findings by Beatrix Hiesmayr, a theoretical physicist at the University of Vienna, and her colleagues, a team of quantum information theory specialists, particle physicists and nuclear physicists, have been published in EPJC.
According to the famous Einstein-Podolsky-Rosen Gedanken-Experiment, two particles that are measured independently obey the principle of locality, implying that an external influence on the first particle, such as measurement, has no direct influence on the second – in other words there is no "spooky action at distance", as Einstein would have described it. In an experimental setup, however, measurement results for one particle revealed a correlated measurement result for the other particle. Initially, these correlations could only be explained by referring to hidden parameters. In 1964, John Bell found that so-called local realistic hidden parameter theories imply that the relations between these correlations could be experimentally tested through so-called Bell tests. Since then many experiments have proven that local, realistic hidden parameters cannot be used as an explanation for these correlations.
In this study, the authors have succeeded in devising a new Bell test, taking into account the decay property of high-energy particles systems, called kaon-antikaon systems. This procedure ensures that the test is conclusive – a goal that has never before been achieved – and simultaneously guarantees its experimental testability. Experimental testing requires equipment such as the KLOE detector at the accelerator facility DAPHNE in Italy.
Revealing “spooky action at distance” for kaon-antikaon pairs has fundamental implications for our understanding of such particles’ correlations and could ultimately allow us to determine whether symmetries in particle physics and manifestations of particles correlations are linked.

Revealing Bell’s Nonlocality for Unstable Systems in High Energy Physics. B.C. Hiesmayr et al., Eur. Phys. J. C (2012) 72: 1856 DOI: 10.1140/epjc/s10052-012-1856-X

January 2012

EPJE - How to build doughnuts with Lego blocks

Controlling forces between oppositely charged polymers opens a new route towards creating vectors for gene therapy

Scientists have uncovered how nature minimises energy costs in rings of liquids with an internal nanostructure made of two chemically discordant polymers joined with strong bonds, or di-blocks, deposited on a silicon surface, in an article published in EPJE.
Josh McGraw and his colleagues from McMaster University, Canada, and the University of Reading, UK, first created rings of di-block polymers that they liken to building doughnuts from Lego blocks due to the nature of the material used. This material has an internal structure discretised like Lego blocks, resulting in rings approximating the seamless shape of a doughnut (see photo of previously unseen nanoscale assemblies which illustrates this press release).
McGraw and his colleagues measured the dynamics of interacting edges in ring structures that display asymmetric steps, i.e., different spacing inside and outside the ring, when initially created. They found that the interaction shaping the ring over time is the repulsion between edges. While the molecular details remain elusive, the source of this repulsion is intuitive: an edge is a defect which perturbs the surface profile with an associated cost to the surface energy.
The edge repulsion prevents two neighbouring edges from getting too near each other. As two isolated edges approach, the perturbation deviates further, thereby deforming the equilibrium edge structure and increasing the free energy. For rings solely subject to the repulsive edge interaction, the authors found that the equilibrium shape of their edges had to be symmetric.
These edges could be considered defects in a material with an otherwise perfect order at the nanoscale. Thus, research based on the elucidation of defect interactions could help scientists trying to eliminate such defects by understanding how these materials self-assemble. Such systems could also provide an ideal basis for creating patterns on the nanoscale, data storage, and nanoelectronics.

Dynamics of interacting edge defects in copolymer lamellae. J.D. McGraw, I.D.W. Rowe, M.W. Matsen, and K. Dalnoki-Veress, Eur. Phys. J. E (2011) 34: 131, DOI 10.1140/epje/i2011-11131-7

January 2012

EPJB - New model for epidemic contagion

Improved estimates on the geographical spread of infectious diseases are achieved by studying human mobility networks

Humans are considered the hosts for spreading epidemics. The speed at which an epidemic spreads is now better understood thanks to a new model accounting for the provincial nature of human mobility, according to a study published in EPJB. The research was conducted by a team lead by Vitaly Belik from the Massachusetts Institute of Technology, USA, who is also affiliated with the Max Planck Institute for Dynamics and Self-Organization, Germany.
The authors modelled human mobility as recurrent trips centred around a home base. The model accounted for the bi-directional travels around a central node, representing their home location and forming a star-shaped network. Previous models were based on diffusion and would imply that people travel randomly in space, not necessarily returning to their home location. These do not accurately describe the high degree of predictability in human mobility.
The researchers found that older diffusion-based models overestimated the speed at which epidemics spread. The speed of epidemics spreading through bi-directional travel, which is dependent on the travel rate, is significantly lower than the speed of epidemics spreading by diffusion.
In addition, the authors discovered that the time individuals spend outside their home locations influences the speed of epidemics spreading and whether an outbreak goes global. This contrasts with previous findings based on diffusion models, which suggested that the rate of travel between locations is the key factor influencing the global outbreak of epidemics.
This model must be tested against real data on human mobility before it can be used as a risk analysis and decision-making tool for epidemics such as avian flu. This model could also be used in areas such as population dynamics and evolutionary biology.

Recurrent hostmobility in spatial epidemics: beyond reaction-diffusion. V. Belik, T. Geisel, D. Brockmann, Eur. Phys. J. B (2011) 84, 579–587, DOI: 10.1140/epjb/e2011-20485-2

January 2012

EPJB - Towards high-temperature superconductors

Scientists produce a new type of superconductor by manipulating graphene, the study of which led to a Nobel Prize

Chinese scientists have manipulated the charge and the degree of freedom, known as spin, of electrons and their associated magnetic properties in a single-layer carbon material called graphene, making it suitable for applications involving superconductivity, a quantum mechanical phenomenon in which electrons travel in a material with no electrical resistance. These findings have recently been published in an article in EPJB by Chunxu Bai from Anyang Normal University and colleagues from the Henan Institute of Science and Technology in Xinxiang.
The authors investigated the means of exploiting a superconducting graphene flake. They looked at how unconventional electron pairing – known as d-wave pairing symmetries – would affect coherent subatomic – i.e., quantum – level transport within the material. In particular, they focused on electrical conductance in a system called a spin valve, which consists of two conducting magnetic materials, including a normal metal and graphene superconductor, the electrical resistance of which alternates from so-called giant magnetic resistance to none, depending on the alignment of its magnetic layers.
By reversing the magnetisation direction of one of the layers of the valve, researchers found that it is possible to achieve a spin-switch effect, whereby a normal current is converted into a superconducting current. The authors also found that the spin-switch effect is sensitive to the incident energy level and the orientation of the material’s superconducting gap.
The authors hope that their theoretical results can provide the basis to design a spin-switch electron device able to operate at so-called high temperature, where liquid nitrogen can be used as a refrigerant at 77 Kelvins (-196 °C) instead of the liquid helium (−269 °C) traditionally used in conventional superconductors. This approach opens doors for the wider use of an all-graphene spin-switch circuit in quantum information applications in the future.

Spin-switch effect in a graphene d-wave superconductor spin valve. C. Bai, J. Wang, H. Tang, and Y. Yang, Eur. Phys. J. B (2011) 84, 1, DOI 10.1140/epjb/e2011-20507-1

December 2011

EPJA - Vector Correlators in Lattice QCD: Methods and Applications

EPJA - Comparison of the vacuum polarisation calculated from e+e- annilhilation cross section with recent lattice simulations

Vacuum polarisation, the modification of the photon propagator due to virtual electron-positron pairs, is one of the first quantum loop corrections encountered in field theory. In both QED and QCD it causes the running of the appropriate fine structure constant as the physical scale is varied, and also corrects the magnetic moments of electrons and muons from the value 2 predicted by the Dirac equation. For scales below a few GeV the QCD vacuum polarisation cannot be calculated perturbatively, but can be accessed via the optical theorem from the annihilation cross section of e+e- into hadrons, which is simply related to the spectral density ρ(s) in the vector isoscalar channel.. This paper opens a new direction by first assessing the current state-of-the-art in calculating the vacuum polarisation in lattice QCD, the most systematic non-perturbative approach, and then by setting out two different routes to improving on this, and identifying applications to strong interaction phenomenology.
Comparison with experimental data reveals that current results are badly finite-volume affected. The paper provides technical details enabling these distortions to be understood and ultimately extrapolated to the large volume limit. It also uses the same data to estimate the current-current correlator as a function of Euclidean time exposing the possibility that different ranges are amenable to different theoretical approaches; the dominant hadronic correction to (g-2) for the muon, about to be measured with unprecedented precision at Fermilab, comes from the range 0.5fm < ct < 1.5fm. This reasoning is also suggests a new QCD reference scale, to help callibrate the lattice spacing using high-precision numerical estimates of the vector correlator.

Vector Correlators in Lattice QCD: Methods and Applications. David Bernecker and Harvey Meyer, Eur. Phys. J. A (2011) 47, 11: 148 DOI 10.1140/epja/i2011-11148-6

December 2011

EPJD - Largest ever gas mix caught in ultra-freeze trap

Towards a better understanding of subatomic particles using a new cold-atom setup

A team of scientists have made it easier to study atomic or subatomic-scale properties of the building blocks of matter (which also include protons, neutrons and electrons) known as fermions by slowing down the movement of a large quantity of gaseous atoms at ultra-low temperature. This is according to a study recently published in EPJ D as part of a cold quantum matter special issue, by researchers from the Paris-based École Normale Supérieure and the Non-Linear Institute at Nice Sophia-Antipolis University in France.
Thanks to the laser cooling method for which Claude Cohen-Tannoudji, Steven Chu and William D. Phillips received the Nobel Prize in 1997, Armin Ridinger and his colleagues succeeded in creating the largest Lithium 6 (⁶Li) and Potassium 40 (⁴⁰K) gas mixture to date. The method used involved confining gaseous atoms under an ultra-high vacuum using electromagnetic forces, in an ultra-freeze trap of sorts.
This trap enabled them to load twice as many atoms than previous attempts at studying such gas mixtures, reaching a total on the order of a few billion atoms under study at a temperature of only a few hundred microKelvins (corresponding to a temperature near the absolute zero of roughly −273 °C).
Given that the results of this study significantly increased the number of gaseous atoms under study, it will facilitate future simulation of subatomic-scale phenomena in gases. In particular, it will enable future experiments in which the gas mixture is brought to a so-called degenerate state characterised by particles of different species with very strong interactions. Following international efforts to produce the conditions to study subatomic-scale properties of matter under the quantum simulation program, this could ultimately help scientists to understand quantum mechanical phenomena occurring in neutron stars and so-called many-body problems such as high-temperature superconductivity.

Large atom number dual-species magneto-optical trap for fermionic ⁶Li and ⁴⁰K atoms. A. Ridinger et al., Eur. Phys. J. D (2011) 65, 1-2, DOI 10.1140/epjd/e2011-20069-4. To see the complete cold quantum matter special issue click here

December 2011

EPJB - Random noise helps make signals clearer

Model shows that signal clarity only improves if specific energy conditions are met

Scientists have shown the energy conditions, under which a weak signal supplied to a physical system emerges as a stronger signal at the output thanks to the presence of random noise (a process known as stochastic resonance), in a paper that has just been published in EPJB.
Stochastic resonance goes against the intuitive idea that where noise is present, the signal tends to fade. It occurs in systems where the response is not proportional to the applied input signal, known as nonlinear systems.
The authors, Shubhashis Rana, Sourabh Lahiri and Arun M. Jayannavar from the Institute of Physics, in Bhubaneswar, India, used a model consisting of a symmetric double-well energy potential in which a particle moves randomly. They studied the effect of the steepness of the walls of the confining energy potential by observing the movement of the particle, which they subjected to an external sinusoidal signal that alternately lowers either of the wells.
The authors selected a quantifier – the average work done on the system by the signal – to determine the conditions under which the particle moving from one well to the opposite side well and back at every cycle of the signal reaches stochastic resonance. They found that it only occurs when the potential is “hard”, meaning that it has sufficiently steep walls, but breaks down otherwise. Previous work used different quantifiers and found similar results, confirming their findings using numerical simulations.
This study contributes to improving scientists’ understanding of stochastic resonance. It could, ultimately, contribute to gaining deeper insights into physics-related phenomena such as the processing of unclear images to increase their resolution* and biological systems, including mechanoreceptor cells in crayfish and the functioning of sensory neurons in humans.

The role of soft versus hard bistable systems on stochastic resonance using average cycle energy as a quantifier. S. Rana, S. Lahiri, A.M. Jayannavar, Eur. Phys. J. B (2011) 84, 2, DOI 10.1140/epjb/e2011-20802-9

December 2011

EPJE - The art of stabilising entangled spaghetti-like materials

Controlling forces between oppositely charged polymers opens a new route towards creating vectors for gene therapy

Gene therapy can only be effective if delivered by a stable complex molecule. Now, scientists have determined the conditions that would stabilise complex molecular structures that are subject to inherent attractions and repulsions triggered by electric charges at the surfaces of the molecules, in a study published in EPJE, by Valentina Mengarelli and her colleagues from the Solid State Physics Laboratory at the Paris-Sud University in Orsay, France, in collaboration with Paris 7 and Evry Universities scientists.
The authors studied soluble complexes made of negatively charged DNA or another negatively charged polymer – polystyrene-sulfonate (PSSNa) – and a so-called condensation agent, which is a negatively charged polymer, known as linear polyethyleneimine (PEI). PEI participates in the condensation process by tying onto a molecule such as DNA, like tangled hair, to form an overall positively charged DNA/polymer complex structure.
Previous research focused mainly on non-soluble complexes, while the few attempts at focusing on soluble complexes dealt either with smaller polymers or those with a weaker electric charge, which may therefore be easier to stabilise.
The French team thus confirmed experimentally that the complexation process does not depend on the rigidity of the original molecule, be it DNA or PSSNa, but on the positive/negative electric charge ratio and on the polymer concentrations. It is the interactions between electrically charged parts within the complex that govern its properties. When the condensation agent is in excess, the positively charged complex is then attracted to negatively charged biological cell membranes. This could be used to deliver the DNA into a targeted cell nucleus as part of gene therapy treatment.
Future work will focus on using long DNA molecules and novel polymers to form complexes of controlled size and electric charge for gene therapy.

Charge inversion, condensation and decondensation of DNA and Polystyrene sulfonate by polyethylenimine. V. Mengarelli et al., Eur. Phys. J. E (2011) 34: 127, DOI 10.1140/epje/i2011-11127-3

December 2011

EPJD - Instant nanodots grow on silicon to form sensing array

New methods for creating 3D nanostructures deposited on an array of regularly spaced indentations on the surface of silicon films opens the door for innovative nanosensors

Scientists have shown that it is now possible to simultaneously create highly reproductive three-dimensional silicon oxide nanodots on micrometric scale silicon films in only a few seconds. Xavier Landreau and his colleagues at the University of Limoges, France, demonstrated in their paper published in EPJ D that they were able to create a square array of such nanodots, using regularly spaced nanoindents on the deposition layer, that could ultimately find applications as biosensors for genomics or bio-diagnostics.
They used a process called atmospheric pressure plasma-enhanced chemical vapour deposition. This approach is a much faster alternative to methods such as nanoscale lithography, which only permits the deposition of one nanodot at a time. It also improves upon other silicon oxide growth processes that do not make it possible to precisely order the nanodots into an array. In addition, it can be carried out at atmospheric pressure, which decreases its costs compared to low-pressure deposition processes.
One of the authors’ goals was to understand the self-organization mechanisms leading to a preferential deposition of the nanodots in the indents. By varying the indents’ interspacing, they made it comparable to the average distance travelled by the silicon oxide particles of the deposited material. Thus, by adapting both the indents’ spacing and the silicon substrate temperature, they observed optimum self-ordering inside the indents using atomic force microscopy.
The next step in their research will be to investigate how such nanoarrays could be used as nanosensors. They plan to develop similar square arrays on metallic substrates in order to better control the driving forces that produce the highly ordered self-organisation of nanodots. Further research will be needed to give sensing ability to individual nanodots by associating them with probe molecules designed to recognise target molecules to be detected.

Ordering of SiO_xH_yC_z islands deposited by atmospheric pressure microwave plasma torch on Si(100) substrates patterned by nanoindentation. X. Landreau et al., Eur. Phys. J. D (2011), DOI 10.1140/epjd/e2011-20503-7

November 2011

EPJB - No extraordinary effects from microwave and mobile phone heating

Study quantifies effects of electric field-induced versus conventional heating

The effect of microwave heating and cell phone radiation on sample material is no different than a temperature increase, according to scientists from the Department of Chemistry and Biochemistry, Arizona State University, in Tempe, as published in a recent issue of EPJ B.

Abidah Khalife, Ullas Pathak and Ranko Richert attempted for the first time to systematically quantify the difference between microwave-induced heating and conventional heating using a hotplate or an oil-bath, with thin liquid glycerol samples. The authors measured molecular mobility and reactivity changes induced by electric fields in these samples, which can be gauged by what is known as configurational temperature.

By conducting experiments at varying field frequencies and sample thicknesses, they realised that thin samples exposed to low-frequency electric field heating can have a considerably higher mobility and reactivity than samples exposed to standard heating, even if they are at the exact same sample temperature. They also found that at frequencies exceeding several megahertz and for samples thicker than one millimetre, the type of heating used does not have a significant impact on the level of molecular mobility and reactivity, which is mainly dependent on the sample temperature. In effect, the configurational temperatures will only be marginally higher than the real measurable temperature.

Previous studies were mostly fundamental in nature and did not establish a connection between microwaves and mobile phone heating effects. These findings imply that for heating with microwave or cell phone radiation operating in the gigahertz frequency range, no other effect than a temperature increase should be expected.

Since the results are based on averaged temperatures, future work will be required to quantify local overheating, which can, for example, occur in biological tissue subjected to a microwave field, and better assess the risks linked to using both microwaves and mobile phones.

Heating liquid dielectrics by time dependent fields. A. Khalife, U. Pathak, and R. Richert, Eur. Phys. J. B (2011) 83, 429 – 435, DOI 10.1140/epjb/e2011-20599-5

November 2011

EPJ C - New Theory Editors-in-Chief and Fermi Prize for Dieter Haidt

The publishers of The European Physical Journal C – Particles and Fields are pleased to announce the appointment of Professors Gino Isidori (Frascati) and Sergei Odintsov (Barcelona) as new theory Editors-in-Chief. This follows the splitting of the theory section into Theory I: Phenomenology of the Standard Model and Beyond, now led by Gino Isidori, and Theory II: Gravitation, Astroparticle Physics and Cosmology, General Aspects of Quantum Field Theories and Alternatives, now led by Sergei Odintsov.

With some 400 published papers totaling over 11.000 citations, Sergei Odintsov has recently been elected by the Russian edition of Forbes among the 10 most influential Russian scientists.

The publishers would also like to congratulate the former Editor-in-Chief of EPJ C, Prof. Dieter Haidt (Hamburg) for having been awarded the 2011 Fermi Prize of the Italian Physical Society for his fundamental contribution to the discovery of weak neutral currents with the Gargamelle bubble chamber at CERN. For more information see http://www.epsnews.eu/2011/10/2011-enrico-fermi-prize/

November 2011

EPJB - Can metals remember their shape at nanoscale, too?

How nickel-titanium nanometric-size particles change back to their memorised shape
University of Constance physicists Daniel Mutter and Peter Nielaba have visualised changes in shape memory materials down to the nanometric scale in an article published in EPJB.
Metallic alloys can be stretched or compressed in such a way that they stay deformed once the strain on the material has been released. Only shape memory alloys, however, can return to their original shape after being heated above a specific temperature.
For the first time, the authors determine the absolute values of temperatures at which shape memory nanospheres start changing back to their memorised shape – undergoing so-called structural phase transition, which depends on the size of particles studied. To achieve this result, they performed a computer simulation using nanoparticles with diameters between 4 and 17 nm made of an alloy of equal proportions of nickel and titanium.
To date, research efforts to establish structural phase transition temperature have mainly been experimental. Thanks to a computerised method known as molecular dynamics simulation, the authors were able to visualise the transformation process of the material during the transition. As the temperature increased, they showed that the material’s atomic-scale crystal structure shifted from a lower to a higher level of symmetry. They found that the strong influence of the energy difference between the low- and high-symmetry structure at the surface of the nanoparticle, which differed from that in its interior, could explain the transition.
Most of the prior work on shape memory materials was in macroscopic scale systems and used for applications such as dental braces, stents or oil temperature-regulating devices for bullet trains. Potential new applications include the creation of nanoswitches, where laser irradiation could heat up such shape memory material, triggering a change in its length that would, in turn, function as a switch.

Simulation of the thermally induced austenitic phase transition in NiTi nanoparticles. D. Mutter, P. Nielaba, Eur. Phys. J. B (2011), DOI 10.1140/epjb/e2011-20661-4

November 2011

EPJD - Not one, not two, not three, but four clones!

First quantum cloning machine to produce four copies
Xi-Jun Ren and Yang Xiang from Henan Universities in China, in collaboration with Heng Fan at the Institute of Physics of the Chinese Academy of Sciences, have produced a theory for a quantum cloning machine able to produce several copies of the state of a particle at atomic or sub-atomic scale, or quantum state, in an article published in EPJ D. This could have implications for quantum information processing methods used, for example, in message encryption systems.
Quantum cloning is difficult because quantum mechanics laws only allow for an approximate copy—not an exact copy—of an original quantum state to be made, as measuring such a state prior to its cloning would alter it. In this study, researchers have demonstrated that it is theoretically possible to create four approximate copies of an initial quantum state, in a process called asymmetric cloning.
The authors have extended previous work that was limited to quantum cloning providing only two or three copies of the original state. One key challenge was that the quality of the approximate copy decreases as the number of copies increases. The authors were able to optimise the quality of the cloned copies, thus yielding four good approximations of the initial quantum state.
They have also demonstrated that their quantum cloning machine has the advantage of being universal and therefore is able to work with any quantum state, ranging from a photon to an atom.
Assymetric quantum cloning has applications in analysing the security of messages encryption systems, based on shared secret quantum keys. Two people will know whether their communication is secure by analysing the quality of each copy of their secret key. Any third party trying to gain knowledge of that key would be detected as measuring it would disturb the state of that key.

Optimal asymmetric 1 –> 4 quantum cloning in arbitrary dimension. XJ Ren, Y Xiang and H Fan , Eur. Phys. J. D (2011), DOI 10.1140/epjd/e2011-20370-2

November 2011

EPJE - How biological capsules respond under stress

Innovative high-precision measuring tool to assess the bending elasticity of liposomes
Cosmetics and pharmaceutical drug delivery systems could be improved thanks to a new method developed to precisely measure the capability of capsule-like biological membranes to change shape under external stress. This work is outlined in a study published in EPJE by Philippe Méléard and Tanja Pott from the Rennes-based Institute of Chemical Sciences at the European University of Brittany and their colleagues from the Center for Biomembrane Physics at the University of Southern Denmark in Odense.
The authors found that, by using a statistical method, they could evaluate the bending elasticity of biological membrane models, a key factor in understanding their physical properties. They relied on a series of video-microscopy images of giant liposomes, which are artificial spherical vesicles of more than 10 micrometers in diameter made of a bi-layer of fatty substance called lipids. They studied the membrane deformations triggered by thermal agitation of molecules in the liquid surrounding them, over time.
Previous approaches used the average of deformation amplitudes observed in these images, which meant a loss of accuracy of up to 20%. Instead, in this study, the authors focused on evaluating the statistical distribution of the membrane deformation, which yielded unprecedented precision. This method relies on the so-called Maxwell-Boltzman statistical distribution, named after James Clerck Maxwell and Ludwig Boltzmann, who studied the kinetic theory of gas using this approach.
The method presented in this paper could be of interest to industry scientists in devising both cosmetic and pharmaceutical applications. For example, industry often needs to encapsulate products such as cytotoxic cancer drugs or antimicrobial peptides in biological membranes prior to delivering them into patients’ bodies. Ultimately, it could help industry scientists determine what type of biological membrane is best suited for their specific purpose.

Advantages of statistical analysis of giant vesicle flickering for bending elasticity measurements. P. Méléard et al., Eur. Phys. J. E (2011) 34: 116, DOI 10.1140/epje/i2011-11116-6

October 2011

EPJ E - How do protein binding sites stay dry in water?
In a report that has just been published in EPJE, researchers from the National University of the South in Bahía Blanca, Argentina studied the condition for model cavity and tunnel structures resembling the binding sites of proteins to stay dry without losing their ability to react, a prerequisite for proteins to establish stable interactions with other proteins in water.
E.P. Schulz and colleagues used models of nanometric-scale hydrophobic cavities and tunnels to understand the influence of geometry on the ability of those structures to stay dry in solution.
The authors studied the filling tendency of cavities and tunnels carved in a system referred to as an alkane-like monolayer, chosen for its hydrophobic properties, to ensure that no factors other than geometrical constraints determine their ability to stay dry.
They determined that the minimum size of hydrophobic cavities and tunnels that can be filled with water is on the order of a nanometer. Below that scale, these structures stay dry because they provide a geometric shield; if a water molecule were to penetrate the cavity it would pay the excessive energy cost of giving up its hydrogen bonds. By comparison, water fills carbon nanotubes that are twice as small (but slightly less hydrophobic) than the alkane monolayer, making them less prone to stay dry.
The authors also showed that the filling of nanometric cavities and tunnels with water is a dynamic process that goes from dry to wet over time. They believe that water molecules inside the cavities or tunnels are arranged in a network of strong cooperative hydrogen bonds. Their disruption by means of thermal fluctuations results in the temporary drying of the holes until new bonds are re-established.
One of the many potential applications is in biophysics, to study water-exclusion sites of proteins, and understand the physical phenomenon linked to the geometry of those sites, underpinning the widespread biological process of protein-protein associations.

Behavior of water in contact with model hydrophobic cavities and tunnels and carbon nanotubes. E.P. Schulz et al., Eur. Phys. J. E (2011) 34: 114, DOI 10.1140/epje/i2011-11114-8

October 2011

EPJ E - What makes tires grip the road on a rainy day?

Scientists examine the flow of liquid at the contact between randomly rough surfaces
A team of scientists from Italy and Germany has recently developed a model to predict the friction occurring when a rough surface in wet conditions (such as a road on a rainy day) is in sliding contact with a rubber material (such as a car tire tread block) in an article that has just been published in EPJE.
In their study, B.N.J. Persson from the Jülich Research Center in Germany and M. Scaraggi from the Polytechnic of Bari in Italy examined the flow of liquid at the contact between randomly rough surfaces. The contact interface looks like a labyrinth with vertically narrow void channels intersecting randomly. This causes channels to be either filled with water or not when in wet conditions.
For the first time, the authors applied a statistical analytical method to determine the average fluid flow at the interface of rough surfaces. Understanding this flow is important because it is inherently linked to the phenomenon of friction at the contact between the two surfaces.
Previous attempts to understand friction in such conditions used numerical approaches that required large computing power. They were based on calculating real roughness contacts by singling out each individual portion of the overall rough surface under study. Often, heavy approximations in the description of the simulated surface were applied to decrease the computational time. The model presented in this paper provides theoretical predictions of friction as a function of the surface sliding velocity. It confirms previous experimental friction measurements made with a smooth steel ball sliding on a rough rubbery surface patterned with parallel grooves. The authors’ model confirmed the experimental observation of a changing friction level related to a change in the angle between the direction of movement of the ball and the parallel to the grooves.
Potential applications would require that such a model be used to help create surfaces, such as microstructured tires, which do not lower their grip when it rains.

Lubricated sliding dynamics: flow factors and Stribeck curve. B.N.J. Persson and M. Scaraggi, Eur. Phys. J. E (2011) 34: 113, DOI 10.1140/epje/i2011-11113-9

October 2011

EPJ A - The Similarity Renormalization Group for Three-Body Interactions in One Dimension

One important message that has emerged from developments of effective field theories and effective Hamiltonians for nuclear physics is that many-body forces are inevitable whenever degrees of freedom are eliminated. At the same time, first-principles calculations have shown that two-body forces alone are not able to give an accurate account of the energies of light nuclei and the saturation of nuclear matter. Three- (and possibly more-) body forces are thus essential in low-energy nuclear physics. The construction of effective interactions through elimination of degrees of freedom can be done either by imposing a cut-off on the Hilbert space or by applying a transformation to put the Hamiltonian into a simpler form, such as a diagonal matrix. The Similarity Renormalization Group follows the latter route by means of a continuous set of transformations. It has proved to be a powerful tool in low-energy nuclear physics, where it has been applied mainly in the context of expansions using harmonic-oscillator basis states.

The present paper provides the first application of this method to three-body interactions in a momentum-space basis. Although the models studied are simple ones, consisting of bosons in one dimension, the structure of the evolution equations has the full complexity of any set of three-body equations. The results show the expected decoupling of high- from low-momentum states for both two- and three-body interactions, which means that only low-momentum matrix elements of the evolved potentials are needed to describe low-energy states. This work paves the way for applications to few-nucleon scattering processes and nuclear matter, starting from realistic nuclear forces in three dimensions.

The similarity renormalization group for three-body interactions in one dimension.
O. Åkerlund et al., Eur. Phys. J. A (2011) 47: 122, DOI 10.1140/epja/i2011-11122-4

October 2011

EPJ C - No sign of supersymmetry

Most stringent limits ever set by ATLAS

"Supersymmetry - to be or not to be?" remains a still unanswered question - it is a traditionally difficult business to demonstrate a zero result in experimental physics - yet the ATLAS collaboration has just set new and very stringent limitations on the "viability space" of a class of new physics models incorporating gauge-mediated supersymmetry breaking.
To this end, the collaboration analyzed all channels where W or Z bosons decay into two photons and at least one neutrino while featuring a large missing transverse energy (i.e. measured in all directions perpendicular to the beam axis), these channels being particularly sensitive to new physics in these models.
No deviations from standard model predictions were observed, putting upper limits to the cross-sections for new physics and thus raising significantly the lower mass limits for postulated supersymmetric particles - e.g. to 560 GeV for the gluino mass at a 95% confidence level (see figure).
As an added "bonus" the same results also contributed to ruling out easily observable extra dimensions - the inverse value of the compactification radius of specific models with one universal extra dimension was estimated to be at least 961 GeV with a 95% confidence level.

Search for diphoton events with large missing transverse energy with 36 pb⁻¹ of 7 TeV proton–proton collision data with the ATLAS detector
The ATLAS Collaboration, Eur. Phys. J. C (2011) 71: 1744, DOI 10.1140/epjc/s10052-011-1744-9

October 2011

EPJ E - Unlocking jams in fluid materials

A new theoretical model which helps to understand how to best avoid jamming of soft matter.

In a study recently published in the European Physical Journal E (EPJE), a German scientist constructed a theoretical model to understand how to best avoid jamming of soft matter that can be applied in food and cosmetics production.
Thomas Voigtmann, a researcher at the Institute for Material Physics in Space in Cologne, Germany, evaluated the internal friction force, or yield stress, to be overcome before a solid material made of a metallic melt with a glass structure can flow and thus prevent jamming.
These materials have an apparent viscosity that drops if they are forced to flow quickly – a property called shear thinning. They are similar to solid paint that is highly viscous, almost solid, in a bucket and can easily become liquid when applied with a brush. The force applied to the paint by a brush stroke is sufficient for shear thinning to occur.
The properties of these metallic melts are not well understood. Until now, these materials have been studied using models for three classes of materials: soft matter (like toothpaste), metallic liquids, or granular materials (like sand).
However, none of these models accurately describes these materials. Instead, Voigtmann devised two models that take into account the common properties between the three material classes; here the goal was to determine whether their yield stress is either continuous (it gets smaller with the flow rate) or discontinuous (remains at a constant value regardless of the flow rate) at a decreasing flow rate. He used available data to test the models; however, further data on lower flow rates than currently available would be required in order to be conclusive.
Further theoretical research will help us to understand how to process large amounts of soft matter for the food industry such as mayonnaise (an emulsion), jelly (a colloidal dispersion), or granular materials such as grains or pharmaceutical pills while avoiding blockages as they flow through processing pipes.
This paper is part of a topical issue of EPJE dedicated to the “Physics of Glasses” edited by Michael Falk, Takeshi Egami and Srikanth Sastry published as European Physical Journal E (EPJE) Volume 34, number 9 (September).

Yield Stresses and Flow Curves in Metallic Glass Formers and Granular Systems.
Th. Voigtmann, Eur. Phys. J. E (2011) 34: 106, DOI 10.1140/epje/i2011-11106-8

September 2011

EPJ D - Quantum teleportation analysed by mathematical separation tool

Scientists from the University of Vienna’s Faculty of Physics in Austria recently gave a theoretical description of teleportation phenomena in sub-atomic scale physical systems, in a publication in the European Physical Journal D.

For the first time, the Austrian team proved that mathematical tools give us the freedom to choose how to separate out the constituting matter of a complex physical system by selectively analysing its so-called quantum state. That is the state in which the system is found when performing measurement, which can either be entangled or not.
The state of entanglement corresponds to a complex physical system in a definite (pure) state, while its parts taken individually are not. This concept of entanglement used in quantum information theory applies when measurement in laboratory A (called Alice) depends on the definite measurement in laboratory B (called Bob), as both measurements are correlated. This phenomenon cannot be observed in larger-scale physical systems.
The findings of the Austrian team show that the entanglement or separability of a quantum state –whether its sub-states are separable or not; i.e., whether Alice and Bob were able to find independent measurements – depends on the perspective used to assess its status.
A so-called density matrix is used to mathematically describe a quantum state. To assess this state’s status, the matrix can be factorised in different ways, similar to the many ways a cake can be cut. The Vienna physicists have shown that by choosing a particular factorisation, it may lead to entanglement or separability; this can, however, only be done theoretically, as experimentally the factorisation is fixed by experimental conditions.
These findings were applied in the paper to model physical systems of quantum information including the theoretical study of teleportation, which consists of the transportation of a single quantum state. Other practical applications include gaining a better understanding of K-meson creation and decay in particle physics, and of the quantum Hall effect, where electric conductivity takes quantisized values.

Entanglement or separability: the choice of how to factorize the algebra of a density matrix
W. Thirring et al., Eur. Phys. J. D (2011) DOI: 10.1140/epjd/e2011-20452-1

September 2011

EPJ E - New complex offers potentially safer alternative for gene therapy delivery

Spontaneous ordering of DNA fragments in a special matrix holds the key to creating non-toxic gene therapy delivery vectors, according to a study recently published in the European Physical Journal E.
Scientists from the CNRS Paul Pascal Research Centre, an institute of the University of Bordeaux, France, and colleagues from the Institute of Physics at the University of Sao Paolo, have created a complex system designed to hold DNA fragments in solution between the hydrophilic layers of a matrix of fatty substances (also known as lipids) combined with a surfactant (used to soften the layers’ rigidity). One possible application that has yet to be tested is gene therapy.
Although gene therapy was initially delivered using viral vectors, recent attempts at devising alternative vectors have exploited positively charged lipids to form complex structures holding DNA fragments with electrostatic forces. However the positively charged ions, known as cations, used in this type of vector have proven toxic for human cells.
Until now, only positively charged fatty substance were thought capable of holding DNA in a complex vector. The authors of this study have proved otherwise by creating an electrically neutral matrix, structured like a multi-layered cake, which holds the DNA fragments at a high concentration in solution between the layers.
The authors found that DNA fragments within the complex self-organise over time. These fragments spontaneously align parallel to one another and form rectangular and hexagonal structures across the layers. The change of atomic-level interactions within the layers and the appearance of interactions at the interface between the layers and the DNA molecules may explain the emergence of ordered structures at high DNA concentrations.
The next step of this research involves elucidating the precise physical forces that hold the complex together. Applications of such technology go beyond gene therapy vector design, as the same principle can be applied for the delivery of other particles such as chemical drugs.

Supramolecular polymorphism of DNA in non-cationic L_α lipid phases
E.R. Teixeira da Silva et al., Eur. Phys. J. E (2011) 34: 83

August 2011

EPJ Plus - The twin paradox in a cosmological context

The twin paradox has been a source of debate since it was discovered by Einstein. It can be analytically verified assuming the existence of global nonrotating inertial frames.
The natural nonrotating frame and its identification with "fixed stars" is an aspect of Mach's Principle, which holds that the totality of matter in the universe determines the inertial frames.
Ø. Grøn and Braeck first note that the experiment by Hafele and Keating (1972), who flew atomic clocks eastward and westward around the Earth in commercial aircraft, also shows agreement with the expected result, assuming an inertial frame which is nonrotating with respect to "fixed stars". The authors then show that in the case of two observers in an otherwise empty universe (i.e., without "fixed stars") moving at different speeds on a circular path yield different twin paradox results, depending on whether one or the other – or neither – observer is assumed to be at rest.
The authors ultimately take a fresh look at the work of Brill and Cohen, who studied the geometry inside a massive rotating shell, and conclude that in the black hole limit, such a mass distribution will drag the frames around at its own rotation rate.
Taken together, and given the entire universe closely satisfying the black hole condition, this paper lends further support to the Mach Principle.
The twin paradox in a cosmological context
Ø. Grøn and S. Braeck, Eur. Phys. J. Plus (2011) 126: 79, DOI: 10.1140/epjp/i2011-11079-7]

August 2011

EPJ Plus - Discovering Technicolor

At present there are no known elementary scalar fields. A possible candidate is the as yet undiscovered Higgs particle; however it could well be that this elusive particle is instead composite. This possibility is exhaustively examined in this article, which is both tutorial and extensive review, classifying the diverse technicolor models as extensions of the Standard Model of particle physics.
These model extensions are then compared with electroweak precision data, the spectrum of states common to most such models are identified, and their decays and associated experimental signals for the LHC illustrated, including the implementation in event generators important for searches at the LHC. This timely review provides the most complete and up-to-date benchmarks for the potential discovery of technicolor models.
Figure: Cartoon of the Minimal Walking Technicolor Model extension of the SM.

Discovering Technicolor
J.R. Andersen et al., Eur. Phys. J. Plus (2011) 126 : 81, DOI: 10.1140/epjp/i2011-11081-1]

August 2011

EPJ B – Online activity grows in a similar pattern to those of real-life networks

The activity of online communities does not grow in line with the number of users, according to a model recently published in the European Physical Journal B.
The Internet has given rise to its own sorting devices. Among these, tagging consists in assigning user-chosen keywords to a piece of information (such as a digital image) to facilitate searches. Lingfei Wu, a researcher at the City University of Hong Kong’s Department of Media and Communication, used the tagging behaviour of social media application users to study the growth of online communities’ activity.
Wu focused on two social media sites: Flickr and Delicious, in which a faster growth of overall tagging activity than of user population was observed. This phenomenon is called accelerated growth and confirms that tagging activity is not correlated in a linear way to the number of social media users using tagging. In this study, Wu suggests that the accelerating growth pattern originates from the effect of the community size on individual tagging behaviour. He found that despite the fluctuation in the number of tags and of the population, communities have a heterogeneity (in terms of individual tagging activity) that remains constant over time, but differs across systems. Given this time-invariant heterogeneity, the average individual activity will grow as the system expands, leading to the accelerating growth of overall activity.
Previous studies focusing on real-world examples such as cities and biological networks exhibited similar growth pattern. This study shows that there are also accelerating growth patterns in the virtual world.
Immediate applications of modelling the online activity growth include predicting the server capacity required for social media sites on the basis of historical data. Future work will focus on devising a unified model that explains the regularity governing the scaling up of both real-life systems (e.g. biological species and cities) and virtual communities.

The accelerating growth of online tagging systems
L. Wu, Eur. Phys. J. B (2011) DOI: 10.1140/epjb/e2011-20187-9

August 2011

EPJB - Atomistic details over longer time scales

The conventional method for atomistic simulation, namely molecular dynamics (MD), is not well suited to resolve slow dynamical processes, that is processes associated with a system that gets trapped from time to time in deep local energy minima.
In a Colloquium paper in the European Physical Journal B, A. Kushima, J. Eapen, Ju Li, S. Yip and T. Zhu review the capabilities of biased molecular simulation methods such as metadynamics, autonomous basin climbing (ABC), strain-boost and adaptive boost simulations – methods designed to probe at the atomic level mechanisms that drive system-level behavior observable on macroscopic time scales.
The authors discuss adaptations of these methods applied to the study of glassy dynamics, creep deformation in stressed solids and diffusion. As these are rather different areas of condensed matter science, the aim is to draw attention to other complex processes involving anthropological or geological time scales, where behavior can be simulated at atomic resolution and understood in terms of micro-scale processes of molecular rearrangements and collective interactions.

Time scale bridging in atomistic simulation of slow dynamics: viscous relaxation and defect activation
A. Kushima et al., Eur. Phys. J. B (2011) DOI: 10.1140/epjb/e2011-20075-4

August 2011

EPJ E - Embryo development obeys the laws of hydrodynamics

The law of hydrodynamics can contribute to our understanding of how a cluster of embryonic cells can transform into an animal within the first 36 hours of development, according to research recently published in European Physical Journal E.
Vincent Fleury, a researcher at the Paris Diderot University, studied the early stage of development when embryonic cells first form a flat sheet of cells before folding into a U-shape, resembling a folded pancake. He demonstrated that the formation of a chicken’s head is a consequence of the collision between both sides of the embryo flowing at constant speed towards each other.
This study captured for the first time on film highly accurate observations of how a chicken embryo evolves during its first two days of development, using time-lapse microscopy. Prior attempts relied on complex imaging techniques that were costly and not as accurate as direct filming. In this study, the embryo was first taken out of its shell, its yolk removed (as it is not needed in the first 48 hours) and it was kept under appropriate temperature conditions.
Previous developmental studies focused on studying each cell individually. In this study, the embryo was considered in its entirety, like a type of plasticine material able to flow like Dali’s melting clocks. The study involved measuring the speed of all points of the embryo and its viscoelasticity in vivo. Combining this data with the biological parameters of the embryo (cells’ viscosity, thickness and overall size), the author created a model of the growing embryo’s movement.
He discovered that the mathematical formula describing magnetic fields could also be used to model fields of vectors representing the hydrodynamic flow of embryonic cells. When the two sides collided, the embryonic cells were subject to forces that can be described as those of two magnets oriented head on, which resulted in the formation of the head.
These findings demonstrate that the head formation does not merely result from a series of discrete events activated by genetic switches. It also shows that chemical gradients are not the prevailing force responsible for movement of cells in early embryo formation, as had been previously thought.
These studies shed new light to on vertebrate development, and could ultimately provide some clues for scientists involved in regenerative medicines.
Similar work on limb development is due to be published in the August issue of the European Physical Journal Applied Physics.

A change in boundary conditions induces a discontinuity of tissue flow in chicken embryos and the formation of the cephalic fold V. Fleury, Eur. Phys. J. E (2011) 34: 73

Additional videos are available at: http://www.msc.univ-paris-diderot.fr/~vfleury/embryoportal0.html

August 2011

EPJB - Disordered networks synchronise faster than small world networks

A study recently published in European Physical Journal B presents observations of how complex systems synchronise over time.

Synchronisation occurs when individual elements in a complex network behave in line with each other. This applies to real-life examples such as the way neurons fire during an epileptic seizure or the phenomenon of crickets falling into step with one another.
In this study, Carsten Grabow and colleagues from the Max Planck Institute for Dynamics and Self-Organization in Göttingen, Germany, created a model to test the speed of synchronisation of complex networks in collaboration with the Warwick Complexity Centre, UK. They tested this model using three very different oscillators acting on complex networks, which are known as Kuramoto, Rössler and pulse-coupled oscillators. As a result, for all tested networks they showed that the structure of the coupling between network nodes determines the speed of synchronisation.
In short: the higher the disorder in the network, the faster the synchronisation.
They subsequently verified this observation in real-life networks including an air-transported network, a social network and a human travel network. Given the great variety of networks used, the increase in the speed of synchronisation in line with increased disorder can be considered universal.
This result goes against previous observations, which showed that so-called small-world networks, which consist of an intermediate structure of fully ordered and fully disordered networks, favour synchronisation. The small-world effect was famously applied to analysing social networks and gave rise to the theory that there are only six degrees of separation between people in a given country.
The authors are currently working on deriving a mathematical formula to predict which complex network would synchronise and how fast. Such an approach would require integrating parameters, including the network size and typical number of links per node, as well as the spread of the disorder introduced. This work could have real-life applications, for example, in measuring the robustness of the relaxation process in gene regulatory networks.

Speed of complex network synchronization C. Grabow, S. Grosskinsky and M. Timme
Eur. Phys. J. B (2011) DOI: 10.1140/epjb/e2011-20038-9

August 2011

EPJ Plus – New analytic method to solve 2-d Helmholtz equation for irregular boundaries

To date the most successful efforts to solve the irregular boundary Helmholtz equation with Neumann boundary conditions have been computational, but even this general method has its drawbacks. Panda et al. provide a new analytic approach which solves the irregular boundary problem via a perturbative series. As the authors show by working out several nontrivial examples, the benefits of this approach include a precise understanding of the behavior of the solution as the amplitude of the boundary distortion is increased, as well as the control over the analytic precision in the terms computed and its corresponding analytic error estimates. more

August 2011

EPJ Plus – Focus on Hadron Therapy in Europe

Oncological hadron therapy was first proposed 65 years ago by Robert R. Wilson, and it took more than 40 years to build the first dedicated facility, in Loma Linda in the nineties. The growth of new facilities since then has been exponential, and thousands of patients are now treated every year. Close collaboration between research institutes, clinical centers and industry is the basis and the future of this field. This EPJ Plus focus issue spotlights the status of hadron therapy in Europe, where different centers are already in operation, some are just now ready to start patient treatments, and new ones are being planned. more

July 2011

EPJ Impact Factors on the rise

The release of the 2010 ISI Impact Factors is cause for celebrations for all EPJ journals. The growing figures underline the commitment of the Editors and Publishers to uphold high standards of scientific quality in physics publishing. A special word of thanks goes to all referees and authors who support the journals and help us make them successful.

EPJ A    IF: 2.592 (was 1.968)
EPJ B    IF: 1.575 (was 1.466)
EPJ C    IF: 3.248 (was 2.746)
EPJ D    IF: 1.513 (was 1.420)
EPJ E    IF: 2.096 (was 2.019)
EPJ AP IF: 0.899 (was 0.756)
EPJ ST IF: 0.838 (was 0.840)

Moreover we are delighted to announce that the most recent additions to the EPJ series, EPJ H – Historical Perspectives on Contemporary Physics and EPJ Plus, are both already accepted for ISI indexation.

July 2011

EPJE - Compare Motor Models: Two-State versus Crossbridge

Rigid two-state and crossbridge are two models of motor assemblies widely used in the literature. But up to now they had never been studied and compared systematically. In cells, motor proteins use chemical energy to generate motion and forces. This thorough comparison presented in EPJE shows that theforce response to a small displacement step is similar in both models to the delayed stretch activation observed in oscillating muscles.
Motors often interact and form clusters because they are connected to a single rigid backbone. In a muscle the backbone is made by association of the motor tails. The backbone motion results from the action of all the motors, and feeds back on each motor. Previous works suggest that motor assemblies are endowed with complex dynamical properties, which may play a role in the mechanisms of heartbeat, flagellar beating, or hearing. This paper studies two models of motor assemblies: the rigid two-state model and the classical crossbridge model widely used in muscle physiology.
Both models predict spontaneous oscillations. In the rigid two-state model, they can have a "rectangular" shape or a characteristic "cusp-like" shape that resembles cardiac sarcomere and "stick-slip" oscillations. The oscillations in the vicinity of the Hopf bifurcation threshold can be much faster than the chemical cycle. This property, not found in the crossbridge model where friction slows down motion, could be important for the description of high frequency oscillations, such as insect wingbeat. Experiments based on the response of a motor assembly to a step displacement are also well described by both theories, which predict non-linear force displacement relations, delayed rise in tension and "sarcomere give". This suggests that these effects are not directly dependent on molecular details. The authors relate the collective properties of the motors to their microscopic properties accessible in single molecule experiments and they show that a three state crossbridge model predicts instabilities even in the case of an apparent load decelerated detachment rate.

To read the full paper “Dynamical behavior of molecular motor assemblies in the rigid and crossbridge models” by Thomas Guérin, Jacques Prost, and Jean-François Joanny, Eur. Phys. J. E (2011) 34: 60, click here.

July 2011

EPJ B welcomes a new Editor-in-Chief for its complex systems section

The publishers of The European Physical Journal B - Condensed Matter and Complex Systems are pleased to announce the appointment of Professor Peter Hänggi as a new Editor-in-Chief, who will specifically contribute to the further development of the physics of complex systems section of the journal. Professor Hänggi will focus on statistical physics and nonlinear dynamics while also exploring in more depth the synergies with the condensed matter section of EPJB. The interdisciplinary physics part of the complex systems section of EPJ B is currently led by Prof. Frank Schweitzer.

Peter Hänggi, a professor of theoretical physics at the University of Augsburg, has received numerous prizes and honors. He is particularly well known for his seminal contributions in the fields of Brownian motors, stochastic resonance, molecular electronics and relativistic thermodynamics.

June 2011

EPJ B - Deciphering complex games

Game theory has changed our way of thinking about socio-economic interaction, shedding light on the consequences of leaving individuals take their choices for the sake of their self-interest. As exemplified by the prisoner's dilemma, the prediction of this approach can be quite far from what welfare optimization would predict. Still, most of the intuition of game theory has been limited to either simple games or to games with few players, that, in many cases, fall short of capturing the complexity of the ``games'' which are played in our societies. Typically, individuals are different and their incentives are different, and they are not only involved in playing games with their neighbors, but their choices have also to take into account the global games they are involved in. Ramezanpour, Realpe-Gomez and Zecchina show how the statistical mechanics approach can be extended to cope with the complexity of these games. This not only shows how to characterize the set of possible (Nash) equilibria of the society, but also helps finding those equilibria, which are typically hard to compute, which have optimal welfare properties.

To read the full paper "Statistical physics approach to graphical games: local and global interactions" A. Ramezanpour, J. Realpe-Gomez and R. Zecchina, Eur. Phys. J. B 81, 327-339 (2011) DOI: 10.1140/epjb/e2011-10963-x click here.

June 2011

EPJ Plus – Alternative Electroweak Model without a Higgs

While the hunt is on for the Higgs at the LHC, model building continues to explore also other scenarios. Here, an ultraviolet complete electroweak model is presented that assumes running coupling constants described by energy-dependent entire functions. Contrary to the conventional formulation the action contains no physical scalar fields and no Higgs particle, even if the foreseen masses for particles are compatible with known experimental values.

In addition the vertex couplings possess an energy scale for predicting scattering amplitudes that can be tested in current particle accelerators. As a result the paper provides an essential alternative to the current established knowledge in the field and addresses an issue that might soon be resolved, as the Large Hadron Collider could provide the experimental evidence of the existence or non-existence of the Higgs boson.

To read the full paper 'Ultraviolet Complete Electroweak Model Without a Higgs Particle' Eur. Phys. J. Plus (2011) please click here.

May 2011

EPJD - Speedier Quantum Logic

Quantum information processing requires logical operations with multiple quantum bits. One route to this goal is controlling each qubit with a time-dependent external magnetic field. In this recent paper published in EPJ D, Heule et al. describe ways to perform logical operations on an ENTIRE superconducting qubit chain by controlling just ONE of the end qubits of the chain.

Strikingly, the authors show that certain operations - e.g., flipping the state of the last qubit in the chain - can be done faster by acting on the first qubit with a magnetic field in the x-direction only, rather than with fields in both x- and y-directions. These faster techniques can speed up logical operations. This paper thus paves the way for faster quantum logic with superconducting qubits.

To read the full paper 'Controlling qubit arrays with anisotropic XXZ Heisenberg interaction by acting on a single qubit' Eur. Phys. J. D (2011) please click here.

May 2011

EPJB – Round-up on the conductivity of carbon nanomaterials

An 8-unit-cell long (10, 0) CNT end-contacted with Au(111) metallic electrodes

A new Colloquium article by I. Deretzis and A. La Magna published in EPJB reviews the possibilities offered by all-carbon electronics as well as elucidating drawbacks in view of future applications.

The lack of an intrinsic badgap in graphene is what hampers its use in semiconducting devices. The most plausible route toward badgap engineering of this material seems to be confinement in one dimension. I. Deretzis and A. La Magna discuss how various sources of non-ideality in quasi one-dimensional structures, such as graphene nanoribbons, carbon nanotubes and linear carbon chains, can impact on the electronic transport characteristics. The authors also analyze the effect of perturbations and modifications to the structural and electronic symmetry in atomistic descriptions that go beyond phenomenological approaches. The article provides a general formalism for the for the calculation of coherent transport in nanodevices, discusses the quantum transport modeling of defective sp2 systems and looks at the important role of the interaction with metallic contacts.

To read the full paper ‘Coherent electron transport in quasi one-dimensional carbon-based systems’ Eur. Phys. J. B 81, 15-36 (2011) please click here.

May 2011

Jean Daillant nominated new Director General of SOLEIL

Congratulations to Prof Jean Daillant, member of the EPJ Steering Committee, on his recent appointment as Director General of SOLEIL, the French national synchrotron facility.

Since 2004, Jean Daillant has been Director of the LIONS laboratory (Laboratoire Interdisciplinaire sur l’Organisation Nanométrique et Supramoléculaire), which forms part of CEA-IRAMIS (Institut Rayonnement-Matière de Saclay).

As a materials physicist, he has been interested in synchrotron radiation since his PhD years at the Université Paris-Sud 11, where he developed X-ray techniques to study polymers. He joined the CEA in 1989 and became Head of the Soft Matter and Interfaces group a few years before becoming joint director of LURE, from 1999 to 2003.

Jean Daillant’s involvement with the European Physical Journal dates back to 1995, when he started to serve as Associate Editor of the Journal de Physique II. From 1998 to 2010 he continued his editorial role with EPJB. Since October 2010 he represents the French Physical Society (SFP) in the EPJ Steering Committee.

Jean Daillant is an expert on synchrotron radiation and in 2009 he co-edited a book on X-ray and neutron reflectivity". Between 2006 and 2010 he headed SOLEIL’s Scientific Council. He will succeed Michel van der Rest as Director General this summer.

April 2011

EPJB – New theory predicts dispersion in porous solids

Modeling the transport of fluids in porous solids is a problem of general interest for its implications in construction engineering, industrial catalysis, hydrology, agriculture and geology. The classical approach uses an equation derived from continuum mechanics which is problematic and often gives incorrect predictions. When the porous medium presents many scales of variability the problem becomes intractable.
In this colloquium paper in EPJB, A. Hunt and co-workers present a new theory that blends concepts taken from random resistor networks and percolations theory and considers the microscopic parameters of the system. The authors test the theory by comparing it with more than 2200 experiments over length scales from a few microns to 100km. The comparison focuses on the dispersivity.
The good agreement between the new theory and experiments requires rethinking the relevance of diffusion and multi-scale heterogeneity. It would also signal the inappropriateness of the classical advection-dispersion equation or any of its derivations to model solute transport.

To read the full paper "Dispersion of solutes in porous media" by A.G. Hunt et al., Eur. Phys. J. B (2011) click here

April 2011

EPJ H - Cosmic Rays: a (partly) untold story

Domenico Pacini in May 1910 (32 years old) while making a measurement. (Courtesy of the Pacini family.)

The work behind the discovery of cosmic rays, a milestone in science, involved many scientists in Europe and the New World fascinated by the puzzling penetrating radiation, and took place during a period characterized by lack of communication and by nationalism caused primarily by World War I. It took eventually from the turn of the century until 1926 before the extraterrestrial nature of the penetrating radiation was generally accepted.
In the work that culminated with high altitude balloon flights, many important contributions have been forgotten and in particular those of Domenico Pacini, who, in June 1911, demonstrated by studying the decrease of radioactivity with an electroscope immersed in water that the radiation today called "cosmic rays" could not come from the crust of the Earth. This was the first time in which the technique of comparison of undersea measurements with measurements at sea level has been used to obtain a result in fundamental physics; this technique will be used in neutrino experiments of the near future.
This article carefully retraces the history of the discovery of cosmic rays and puts the unfolding story in both the political and scientific contexts. With the help of material previously unknown to the history of science, for example the nominations for the Nobel prizes related to cosmic ray research and the relevant internal reports of the Swedish Royal Academy of Science, and letters exchanged between Victor Hess and Pacini, a more complete view of this fascinating discovery is possible.

To read the full paper "Nationalism and internationalism in science: the case of the discovery of cosmic rays" by P. Carlson and A. De Angelis, Eur. Phys. J. H 36, 309-329 (2010) click here

March 2011

EPJD - 'Measurement of Quantum Mechanical Operators' Revisited

Quantum mechanical measurements are often assumed to be accurate and repeatable. However, due to a fundamental result of Wigner (1952) and Araki and Yanase (1961), we now know that there are limitations to these properties in the presence of a conserved quantity that does not commute with the observable to be measured. Despite its importance and impact on quantum technologies, the full scope of this so-called WAY theorem has remained unclear.

In this recent paper in EPJ D, authors Loveridge and Busch combine case studies and extensions of existing theorems to provide a synthesis which sheds new light on the significance of the repeatability requirement. Their analysis highlights yet another condition that has remained largely underestimated: the requirement that the apparatus pointer observable commutes with the conserved quantity. They show that this condition alone entails that good measurement accuracy and repeatability can only be achieved if the apparatus has a large spread in the conserved quantity. The necessity of this size constraint is established for the first time in a model-independent way. Conversely, it is shown that there is no such size requirement for realizing arbitrarily accurate and repeatable, momentum-conserving measurements of position if one chooses a pointer that does not commute with momentum. With this result a long-standing open question posed by Stein and Shimony has thus been answered affirmatively.

To read the full article "'Measurement of Quantum Mechanical Operators' Revisited", L. Loveridge and P. Busch, Eur. Phys. J. D (2011), click here.

March 2011

EPJ D - Feshbach resonances in the ⁶Li-⁴⁰K Fermi-Fermi mixture: Elastic versus inelastic interactions
(Cold Quantum Matter - EuroQUAM special issue)

Interaction control in a trapped Fermi-Fermi mixture of ⁶Li and ⁴⁰K atoms via a magnetically tuned Feshbach resonance.

Ultracold mixtures of two fermionic species hold great promise for synthesizing novel types of few and many-body quantum states. Magnetically tunable Feshbach resonances are the key to controlling the interaction in such systems. In this article in EPJD, Naik et al. present a state-of-the-art characterization of Feshbach resonances in the Fermi-Fermi mixture of ⁶Li-⁴⁰K atoms, in particular concerning the interplay of both elastic and inelastic scattering. The authors first report a thorough case study of a promising resonance near a magnetic field strength of 155G. Their comparison of these experimental results with theory highlights the high level of understanding gained for the system. The paper then further surveys other resonances; these results will allow experimentalists to identify the most suitable “tuning knobs” for such a Fermi-Fermi system. The deep understanding gained from this data of collision properties on the two-body level lays the ground for all future applications concerning complex quantum states of resonantly interacting fermionic matter.
To read the full paper 'Feshbach resonances in the ⁶Li-⁴⁰K Fermi-Fermi mixture: Elastic versus inelastic interactions', by D. Naik et al., Eur. Phys. J. D (2011), click here

March 2011

EPJ D – Nanodroplets make perfect hosts

Helium nanodroplets provide a unique matrix for the spectroscopy of embedded atom species. In this recent paper in EPJD, Bünermann and Stienkemeier demonstrate a new model of how effects such as droplet shrinking, momentum transfer and cluster desorption affect the pick-up statistics of alkali atoms in helium nanodroplets. To develop this model the authors produced new experimental results, detailed in the article, which include complete doping curves for potassium cluster sizes up to 9. Simulations based on the model closely matched the experimental data. Further, the authors show that this method can also be used to derive information on the spin statistics of formed clusters. This paper thus provides a new and useful tool for embedded species spectroscopy.

To read the full article, 'Modeling the formation of alkali clusters attached to helium nanodroplets and the abundance of high-spin states', O. Bünermann and F. Stienkemeier, Eur. Phys. J. D (2011), click here.

March 2011

EPJ E - Pierre Gilles De Gennes Prize awarded to Michael E. Cates

The second edition of the EPJE - Pierre Gilles De Gennes Lecture Prize will be hosted in Vienna, during the 8th Liquid Matter Conference.

The Editors in Chief of EPJE elected Prof. Michael E. Cates of the University of Edinburgh, UK, as the prize recipient for 2011 in recognition of his outstanding and deeply influential contribution in soft matter science. Mike Cates’ research interest in soft matter spans surfactants, colloids, polymers, emulsions, slurries and granular media. Previous awards to Mike Cates include the Gold Medal of the British Society of Rheology and the Dirac Medal and Prize of the Institute of Physics.

This initiative of the European Physical Journal E - Soft Matter and Biological Physics, takes the name from the illustrious Nobel laureate who founded the journal. The prize is sponsored by the publishers of EPJ, namely EPD Science, SIF and Springer.

March 2011

EPJ E - Polymersomes made-to-measure

The use of polymersomes in drug delivery, medical imaging, micro-reactors or to mimic biophysical membrane phenomena is greatly dependent on the extent to which their properties can be controlled and tuned.

Polymersomes are vescicular structures made from the self-assemby of block copolymers. Since the late nineties they have been the subject of intense research. A Colloquium in EPJ E reviews the various approaches to modulating the properties and behavior of polymersomes based on either molecular design of the constituting blocs or addition of specific components to the membrane. The different approaches allow modulations from the physical, structural and functional points of view.

To read the full article ‘Recent trends in the tuning of polymersomes’ membrane Properties’, J. -F. Le Meins, O. Sandre and S. Lecommandoux, Eur. Phys. J. E (2011) 34: 14, click here.

March 2011

EPJ B - Solids under pressure

Constant-pressure molecular dynamics simulations allow the study of systems where external pressure is a driving force for a structural transformation.
In this colloquium paper in EPJB, Roman Martoňák reviews various approaches to computer simulations of pressure-induced structural transformations in various kinds of solids with a focus on the recent developments in simulation methodology, such as metadynamics and transition path sampling applicable to the study of structural phase transitions in crystals. The application of the techniques to bulk and finite systems is illustrated by several examples. The author argues that computer simulations nowadays provide a solid route to study structural transformations, and are capable not only to complement experiments, but have also a predictive power, especially when ab initio techniques are used.

To read the full paper 'Atomistic simulations of pressure-induced structural transformations in solids', by R. Martoňák, Eur. Phys. J. B 79, 241-252 (2011), click here.

March 2011

EPJ E – Simple routes to surface-attached polymer layers

Electrodeposition of an electroactive polymer and subsequent polymerization of monomers is a novel route to anchor polymer chains to electrode surfaces.

A colloquium paper in EPJE reports the combination of the so-called “grafting through” approach and the formation of conjugated polymer networks. This tandem approach makes it possible to obtain films with double or multi-component polymer systems. Moreover it’s versatile as it enables deposition on any conducting surface.

These types of films are useful for distinct polymer multilayers made of electro-optically active conducting polymers and insulating vinylic and functional polymers that are chemically bound. Such films have potential applications in display devices, sensors, anti-corrosion coatings, controlled wetting surfaces, and anti-static materials.

To read the full paper ‘RAFT “grafting-through” approach to surface-anchored polymers: Electrodeposition of an electroactive methacrylate monomer’, C. D. Grande, M. C. Tria, M. J. Felipe, F. Zuluaga and R. Advincula, Eur. Phys. J. E (2011) 34, 15, click here.

February 2011

EPJ E - Gems for polymer scientists

Tiny polymer droplets that crystallize on a surface are a shrewd expedient to study the birth of a polymer crystal by the elusive homogeneous nucleation mechanism. In most cases, take for example the dust particle in a snowflake, nucleation starts from a heterogenous defect. Homogenous nucleation is difficult to study because of the prevalence of defects in any bulk sample. Crystallization in small droplets alleviates this difficulty in a manner that is conceptually simple: subdivide the system into more domains than the number of defects. If the domains greatly outnumber the defects then only the homogenous mechanism can induce nucleation in a defect free compartment.

Such an approach, reported in EPJ E, has been used to investigate nucleation in polyethylene (PE) droplets. A polystyrene layer forms an unfavorable surface for a thin PE film. On heating, the unstable PE film dewets to form tiny droplets, much like water beading up on a waxy leaf. The result is a sample made of thousands of droplets that can be monitored simultaneously through optical microscopy. This is an ideal setting in which a nucleation event becomes easily distinguishable by the rapid growth of the crystal. Each droplet becomes an isolated independent nucleation experiment and studying homogenous nucleation becomes straightforward.

Relating the probability of homogenous nucleation to the size of the droplet, the authors show that nucleation is surface activated. Stated most simply, a droplet with twice the surface area is twice as likely to nucleate, indicating that the perturbation induced by the interface favours crystal nucleation.

To read the full paper “Surface nucleation in the crystallization of polyethylene droplets” J.L. Carvalho and K.Dalnoki-Veress, Eur. Phys. J. E (2011) 34: 6, click here.

February 2011

EPJ B - Geometry matters

A colloquium published in EPJ B provides a thorough formulation of the theory of the insulating state by means of geometrical concepts, which were somewhat hidden and implicit in the original literature.

In 1964 Kohn published the milestone paper "Theory of the insulating state", according to which insulators and metals differ in their ground state, the key difference being the organization of their electrons. However, the theory of the insulating state remained somewhat incomplete until the late 1990s. The modern theory of the insulating state encompasses all kinds of known insulators, including band insulators, Mott insulators, Anderson insulators, quantum Hall insulators, Chern and topological insulators.

To read the full paper The insulating state of matter: a geometrical theory, R. Resta, Eur. Phys. J. B 79, 121-137 (2011) click here.

February 2011

EPJ A – Validating Aspects of the Strong-Coupling Regime of QCD

A key to our understanding of Quantum Chromodynamics (QCD) in the strong regime is our ability to reproduce the hadronic excitation spectrum. Up to now, and due to their limited predictive power, quark models forecast of this spectrum at high excitation energies is unsatisfactory and is dubbed ``the missing resonances problem”. To explore the high excitation energies in the hadron spectrum production or scattering of heavier mesons from a nucleon target is essential.

In a recent tour-de-force experiment [Eur. Phys. J. A, Volume 47, n. 1, January 2011] I. Jaegle et al. report on an impressive first measurement of η’ photoproduction off a deuteron target at beam energies between 1.47 - 2.45 GeV at the tagged photon beam of the ELSA electron accelerator. Differential cross sections with a wide angular coverage were derived for quasi-free production both on protons and neutrons validating the quasi-free picture. And the first estimate of the coherent γd → dη’ contribution is found consistent with an impulse approximation, pointing to a viable isospin composition model amplitudes and weak final state interactions.

Legendre polynomials coefficients from angular distributions fits of this experiment and world data are reported in Fig. 1 where proton and neutron cross sections for photon energies above 2 GeV, in a region where contributions from t-channel exchange are important, display a similar behavior. At lower photon energies from where the proton cross section peaks, the behavior is different and would require polarization observables for future investigation.

From left to right of panels in Fig. 1, we have the inclusive reaction data first, then the world free and, this experiment, quasi-free proton data and last quasi-free neutron data from coincidence and an extraction of proton from deuteron inclusive data. Solid lines: solution (I) NH model, dashed lines: η′-MAID for neutron and dotted lines: CLAS proton data.

February 2011

EPJ Plus publishes first Focus Point - Major Advances in HEP Software

The need to store, distribute and analyze the 15 million gigabytes of data annually generated by the Large Hadron Collider (LHC) at CERN has led to a revolutionary development of innovative software tools. Under CERN coordination, leading IT teams have tested and validated cutting-edge software technologies aimed to operate distributed computing and data storage infrastructures based on a worldwide network of hundreds of computing centers on an unprecedented scale. Such impressive achievements have allowed several thousands of scientists in hundreds of research institutes and universities around the world to participate in the LHC experiments and access a huge amount of experimental data, equivalent to more than 1.7 million dual-layer DVDs a year, in real-time.

This first EPJ Plus focus point deals with the above-mentioned hot issues in software technologies valued by the high-energy physics computing community. It delivers high-quality peer-reviewed papers written by internationally recognized scientists, which encompass the most effective results achieved to date.
Eugenio Nappi, guest editor

February 2011

EPJ B - Complexity Theory and the National Baseball Hall of Fame

Individual success in competitive endeavors, such as sports or academia, is the result of many factors, some of which are time-dependent. In order to compare human achievements from different time periods, we need to normalize success metrics so as to avoid a time-dependent bias in the comparison of the statistical measures. A novel 'detrending' approach presented in EPJ B removes precisely this bias and allows for an objective comparison across time.
Using this approach the authors scrutinized the highly competitive (US) Major League Baseball and its rich history of over 130 years. The study accounts for factors such as performance-enhancing drugs, changes in the construction of bats and balls, sizes of ballparks, and the talent dilution of players as a result of expansion. The authors find that after applying their normalization method the distributions of career success do not change with time.
The study also addresses two relevant cultural questions: (i) how to quantitatively account for economic, technological, and social factors that influence the rate of success in competitive professions; and (ii) how to use career statistics in an unbiased fashion to help in the both the standard and retroactive induction of athletes into the Hall of Fame. This is a topical issue given the recent 'inflation' observed for home runs in Major League Baseball, a phenomena that is believed to be related to the widespread use of performance-enhancing drugs (PED).
To read the full paper "Methods for detrending success metrics to account for inflationary and deflationary factors" by A.M. Petersen, O. Penner, and H.E. Stanley, Eur. Phys. J. B 79, 67–78 (2011) click here.

January 2011

Jean-Marc Di Meglio becomes Editor in Chief of EPJ E

We are very pleased to announce that Jean-Marc Di Meglio, Physics Professor at the University Paris Diderot, has been appointed Editor in Chief of EPJ E, with the special title of Commissioning Editor in Chief. From 1981 to 1994 he worked in the laboratory of Pierre-Gilles de Gennes at College de France, and was Professor at the University of Strasbourg from 1994 to 2002 The European Physical Journal E has benefitted from his editorial talent and vast expertise since 2007, when he joined the Editorial Board of the journal. Professor Di Meglio's work ranges from soap films to bubbles, polymers, colloids and vesicles. His latest interest is in biomechanics. Professor Di Meglio will work alongside Editors in Chief Daan Frenkel and Frank Julicher. We wish him a great experience in his new role.

January 2011

EPJ D - Reshaping Quantum Light

A photon is not a point: its wavepacket stretches out in space. In the classical limit, this spatial profile is governed by Maxwell's equations, and reshaping it has been a goal in optics since Galileo's invention of the telescope. In this paper, Morizur and his colleagues describe a new Unitary Programmable Mode Converter, a device capable of changing the spatial shape of quantum light at will without introducing loss in the beam.

Losses are particularly detrimental in quantum science because they destroy the non-classical nature of a beam with a well ordered flux of photons. The authors tested their device on such a beam of photons, successfully reshaping the wavepacket while retaining the non-classical nature of the flux. By efficiently adapting the spatial shape of the light emitted from a quantum light source, this device paves the way for the use of non-classical light to enhance optical measurements and microscopy.

Click here to read the full paper, "Spatial reshaping of a squeezed state of light" by J.-F. Morizur, S. Armstrong, N. Treps, J. Janousek and H.-A. Bachor, Eur. Phys. J. D 61, 237-239 (2011).

December 2010

EPJ B – Au and Cu as building blocks of high-density memory devices

Gold and copper atoms adsorbed on a NaCl surface behave as isolated atoms and complex electronic interactions with the surface are negligible. A study by a group of Brazilian researchers uses first-principles simulations to measure the electronic and magnetic properties of gold and copper atoms adsorbed on NaCl(001) surfaces, as well as the modifications in these properties upon charge injection.

The results presented in EPJ B show that neutral Au and Cu adatoms on NaCl(001) interact weakly with the ionic substrate. Magnetization values are close to those of the corresponding isolated atoms, with spatial distributions concentrated mainly around the adatoms. The magnetization comes from the unfilled s valence orbital of the adatoms, and its value drops to zero when a single electron is injected in the adatom and fills its s shell.

Quantifying and manipulating the magnetic moments of the adsorbed atoms is essential to exploit the these systems for producing ultra-high density magnetic memory devices. Experimentalists have already shown the feasibility of manipulating the adatom charge and magnetization with an STM tip.

To read the full paper “Au and Cu Atoms on NaCl(001): a single-atom based memory device prototype?” by A.S. Martins et al., Eur. Phys. J. B 78, 543–546 (2010) click here.

December 2010

EPJ E - How the fruit fly got its spots

The eye of the Drosophila (fruit fly) is characterized by a neat hexagonal patterns, a fascinating system to study pattern formation in biology. A recent paper published in EPJ E proposes a new mechanism to explain the emergence of this pattern.

Researchers at the University of Michigan, Ann Arbor examined a spatially discrete, three variable reaction-diffusion model inspired by the interactions that create a periodic pattern of gene expression in the Drosophila eye. This model creates a regular pattern behind a moving front, as observed in eye discs, through a novel “switch and template” mechanism. In order to better understand this mechanism, the authors performed a detailed study of the model’s behaviour in one dimension, using a combination of analytic methods and numerical searches of parameter space. They find that patterns are created robustly, provided that there is an appropriate separation of time scales and that self-activation is sufficiently strong. The model operates in a strongly nonlinear regime where the final pattern depends on the initial conditions as well as on parameter values. This study highlights the important role that cellularisation and cell-autonomous feedback can play in biological pattern formation.

To read the full paper "Switch and template pattern formation in a discrete reaction-diffusion system inspired by the Drosophila eye" by M.W. Pennington and D.K. Lubensky, Eur. Phys. J. E 33 (2010) click here.

December 2010

EPJ to announce Open Access plans in the course of 2011

In order to foster and accelerate the development of full Open Access publishing in the physical sciences, as well as to coordinate better with the successful existing hybrid physics journals portfolio, Springer's STM division and BioMed Central have agreed to transfer and integrate PhysMath Central into a new initiative of the European Physical Journal (EPJ), EPJ.Open. EPJ.Open is a series of new, fully Open Access Physics journals to complement the existing portfolio of EPJ titles.

EPJ, a collection of well known physics journals jointly published by Springer, EDP Sciences and the Italian Physical Society (SIF) will announce its plans for full open access publishing in the course of 2011.

This development will benefit the Physics community due to the combined strength of Springer Science - with its strong global presence and long history of physics publishing - and BioMed Central - who operate a portfolio of over 200 open access journals and have demonstrated the ability to develop and sustain large scale Open Access operations.

November 2010

Kari Dalnoki-Veress wins Rutherford Memorial Medal

Professor Kari Dalnoki-Veress of McMaster University, Canada, Associate Editor of EPJ E, has been awarded the 2010 Rutherford Memorial Medal of the Royal Society of Canada for outstanding research in Physics.
Founded in 1882, the Royal Society of Canada is the country's oldest and most prestigious scholarly organization. The Royal Society selection committee addressed Dalnoki-Veress as "a dedicated young scientist with a genius for simple but profound investigation. In a short time he has developed an outstanding international reputation in the area of soft matter physics and biophysics. In an era dominated by large funding initiatives and complex instrumentation, Dalnoki-Veress is an inspired scientist and research supervisor who can find deep insight from brilliant direct experiments."
The award will be presented on November 27 2010 during the Society's Induction and Awards Ceremony in Ottawa. The EPJ E journal team sincerely congratulate Kari of this great achievement.

November 2010

EPJ B – A step up in the game of electron-ion dynamics simulations

A Colloquium paper by McEniry et al. published in EPJ B surveys the theory and applications of a new family of computational methods, namely Correlated Electron-Ion Dynamics, which enable the simultaneous evaluation of the electronic current, along with the current-induced forces and subsequent motion of the nuclei.
The classic method to investigate the non-adiabatic exchange of energy between electrons and nuclei is Ehrenfest Dynamics. It is simple and most efficient to implement but it’s unable to capture the effects of inelastic scattering of electrons and the subsequent motion of the atoms. A new Correlated Electron-Ion Dynamics (CEID) approximation has been developed to deal with quantum interference. For weak electron-phonon coupling, the mean field second moment approximation has been found to be very useful, though it can suffer from stability problems. However it is currently the method of choice for including inelastic effects in transport simulations of nanostructures. When the electron-phonon interaction is strong (as occurs in conjugated polymers) there is a higher order CEID formalism available. The robustness and systematic extensibility of this approach allows one to follow the coherent motion of electrons and nuclei.
Click here to read the full paper “Modelling non-adiabatic processes using correlated electron-ion dynamics” by E.J. McEniry, Y.Wang, D. Dundas, T.N. Todorov, L. Stella, R.P. Miranda, A.J. Fisher, A.P. Horsfield, C.P. Race, D.R. Mason, W.M.C. Foulkes and A.P. Sutton, DOI: 10.1140/epjb/e2010-00280-5, Eur. Phys. J. B 77, 305-329 (2010)

November 2010

EPJ H - Foundations of Quantum Statistical Physics Revisited

There is a divide, in quantum statistical physics, between the "ensemblists" who regard thermal equilibrium as a property of an ensemble (or a mixed state) and the "individualists" who regard thermal equilibrium as a property of an individual system (in a pure state). A long forgotten concept of equilibrium put forward by John von Neumann in 1929 is reanalyzed and shown to be influenced by both approaches, yet to be mainly based on the individualist view - a view that has gained ground recently. Click here to read the full paper "Long-time behavior of macroscopic quantum systems" by S. Goldstein, J. L. Lebowitz, R. Tumulka and N. Zanghì, Eur. Phys. J. H 35, 173-200 (2010).

October 2010

EPJ D - Ions that love DNA to bits

Low energy carbon ions have been directed to small DNA strand. The results provide new information of the mechanisms of DNA damage during ion beam therapy, also called hadron therapy.
The clinical success of hadron therapy, where proton and ions with energies of below 150 MeV are used in the treatment of many tumour types, has heightened the interest in the fundamental interactions between ion beams and with biomolecules. Along the radiation track of the primary heavy particle, a large number of ions lose their energy due to inelastic scattering and many low energy secondary fragments (electrons and ions) are produced within the tissue. If such secondary species are formed in the close vicinity of the nucleus of living cell, they can cause significant DNA damage. However the molecular mechanisms by which such damage occurs remains unclear and is a clear limitation to the further development of ion beam therapy.
The recent work published in EPJ D used a mass spectrometer to reveal the length and chemical composition of the fragments caused by carbon ion beam. The fragmentation yield mainly depends on the nucleobase composition and not on the other components of DNA, i.e. sugar and phosphate group. This result tells us which parts of the DNA are most susceptible to such radiation damage and may then be used to improve radiotherapy techniques.

Click here to read the full paper "Desorption of small ionic fragments from oligonucleotides induced by low energy carbon ions" by S. Ptasinska et al., Eur. Phys. J. D 60, 59-63 (2010).

October 2010

Daan Frenkel wins Soft Matter and Biological Physics Award

Professor Daan Frenkel (Cambridge University), Editor in Chief of EPJE is the 2010 recipient of the Soft Matter and Biological Physics award for his contributions to the development and application of computational methods that have transformed our understanding of soft and biomolecular materials.

The Royal Society of Chemistry established this award in 2008. The award will be officially presented to Daan Frenkel in spring 2011. The publishers and the EPJ E journal team congratulate Daan Frenkel on this prestigious achievement.

October 2010

Discounted Open Access fee for Physical Society members

Members of the European Physical Societies represented in the EPJ Scientific Advisory Committee who choose to publish their EPJ paper in open access enjoy a 10% discount on the open access fee. For detailed information on how open access works in EPJ please click here.

October 2010

EPJ D – Measurements in the hot spot of a plasma

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.
Click here to read the full paper "On plasma parameters of a self-organized plasma jet at atmospheric pressure" J. Schäfer, F. Sigeneger, R. Foest, D. Loffhagen, and K.-D. Weltmann, Eur. Phys. J. D (2010).

October 2010

EPJ B – Longitudinal polarization analysis, SANS souci

Ground breaking experiments in EPJ B by D. Honecker and colleagues on an FeCr two-phase nanocrystalline alloy demonstrate the power of one-dimensional neutron-spin analysis in a small-angle neutron scattering (SANS) experiment.
With this method it becomes possible to measure partial correlation functions, and observe several novel anisotropies and asymmetries in the magnetic scattering cross section. The authors measure the scattering intensities that connect two neutron-spin states in FeCr two-phase nanocrystalline alloy and, through the analysis of the spin-flip data, they obtain the (isotropic) longitudinal correlation function and the transversal contributions of the magnetization. This technique opens up the unique possibility for analyzing independently the three vector components of the bulk magnetization, and has the potential to push forward our understanding of magnetic interactions in nanostructures.
To read the full paper, "Longitudinal polarization analysis in small-angle neutron scattering", D. Honecker, A. Ferdinand, F. Döbrich, C.D. Dewhurst, A. Wiedenmann, C. Gómez-Polo, K. Suzuki and A. Michels, European Physical Journal B 76, 209-213 (2010), click here.

September 2010

EPJ D – Phase equations describe birdsongs

Image from Photo.com: 95825077 – maltese canary

The air sac pressure patterns used by domestic canaries during song were analyzed by a group of Argentinean statistical physicists in terms of phase equations.
Many motor patterns in biology are surprisingly simple, particularly taking into account that they are generated by thousands of neurons operating in a non-synchronous regime. For example, during song domestic canaries generate periodic fluctuations in their air sac pressure for uttering different syllables. Each time the air sac pressure exceeds a threshold value, a syllable is uttered. Yet, the different pressure pulses are not arbitrary. The particular shapes of the time series data coincide with the solutions of a low dimensional dynamical system.
Inspired by this finding, the authors address the general issue of the emergence of low dimensional, non trivial dynamics out of large, complex interacting units. The analysis suggests a new mechanism for dimensionality reduction in the dynamics of complex systems.
Click here to read the full article by L.M. Alonso et al., Eur. Phys. J. D (2010).

September 2010

Geysers of Helium burst as if liquid

New experiments on the flow of solid He through a microscopic hole reveal a mechanism that triggers the geysers based on the breakdown of a plug located upstream of the source chamber.
The vacuum expansion of solid helium through a micrometric orifice was suggested as a mean to inject excess vacancies into the solid bulk [R. Grisenti et al, J. Electr. Spectr. 129 (2003) 201]. But while the He flow seems smooth, unexpected periodic bursts out of the orifice (geyser effect) are observed during these vacuum expansion experiments.
The results presented in this Highlight paper indicate that the geyser collapse does not occur near the orifice, as previously suggested, but at a plug in the feed line upstream of the source chamber. Each collapse is triggered by the increasing vacancy concentration which makes the solid behave much as a liquid.
On this basis, Benedek, Nieto and Toennies argue that vacuum expansion provides a novel approach for investigating exotic non-equilibrium phases of quantum solids such as helium.
Click here to read the full article: Giorgio Benedek, Pablo Nieto and J. Peter Toennies 'The Geyser effect in the expansion of solid helium into vacuum' Eur. Phys. J. B 76, 237–249 (2010)

September 2010

EPJ D - New call for papers on cold quantum matter

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.
Quantum Matter is matter in which all the constituent atoms and molecules are in a single quantum state and behave coherently as a single quantum object. Since the first realization of Bose-Einstein condensation (BEC) many new physical phenomena have emerged, and the first applications (such as atomic clocks) have been established.
This EPJ D topical issue will focus on recent advances in the diverse areas covered by the ESF Eurocores Network "Cold Quantum Matter EuroQUAM". However, the topical issue is not exclusively reserved to the themes of the Cold Quantum Matter EuroQUAM, but it is open to all original contributions from experts in the field of Cold Quantum Matter.
Guest Editors: Gerhard Birkl, Christopher Foot, Tim Freegarde, Rudolf Grimm, Jeremy Hutson, Matthias Weidemller.
Deadline for submission: December 31, 2010.
Contributions are welcome on https://articlestatus.edpsciences.org/is/epjd/. Please select "Cold Quantum Matter Achievements and Prospects" under the Special Issues tab. Contributions can also be sent directly to epjd[at]edpsciences.org
To read the full call for papers click here.
To read all open calls for papers click here.

July 2010

EPJ D - Gaetana Laricchia wins Thomson Medal

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.
Professor Laricchia's achievements include measurements of near - threshold ionisation which have led to the development of new threshold laws. Her unique kinematically complete measurements (in which the energy distribution among all particles is accounted for) of direct ionisation by positron impact revealed the occurrence of electron - capture - to - the - continuum. This work also exposed an unexpected symmetry in the energy sharing between the ejected electron and the positron which theorists are still struggling to explain.
Professor Laricchia was appointed Associate Editor for EPJ D in January 2010. The whole editorial team and the publishers congratulate her on this prestigious award.

June 2010

EPJ C article selected Fast Breaking Paper by ScienceWatch
The physics paper with the highest percentage increase in citations so far in 2010, as determined by ScienceWatch.com, is `Parton distributions for the LHC' by A Martin et al. Eur.Phys.J.C63:189-285, 2009 This article has meanwhile been cited over 200 times, according to the reference database for high-energy physics, SPIRES. The paper was already selected as highlighted article by the editorial board of EPJ C, featuring on the cover of the September 2009 issue of this journal.

Sources:
ScienceWatch: http://sciencewatch.com/dr/fbp/2010/10junfbp/
IPPP Durham http://www.ippp.dur.ac.uk/modules/news/news_0024.html?uri=/News/index.html
SPIRES: http://www.slac.stanford.edu/spires/find/hep/www?irn=8100632

June 2010

EPJ E - Bendy interfaces
The shape of the interface between two fluids can be controlled by changing the refractive index contrast between the fluids, researcher from the Universite Bordeaux have shown. Optofluidics are methods based on the combination of optics and fluidics which have recently promoted innovative approaches to manipulate liquid interfaces. Since flows are optically driven, researchers call this emerging field optohydrodynamics. The recent paper published in EPJ E presents a fine example of optohydrodynamic actuation at the microscopic scale, based on experimental and predictive numerical results. This work illustrates one of the simplest manifestations of optohydrodynamics and provides a frame to anticipate further developments of contactless interface micromanipulation by lasers.

To read the full paper ‘Optohydrodynamics of soft fluid interfaces: Optical and viscous nonlinear effects’ by H. Chraibi et al. click here

June 2010

EPJ E - Pierre-Gilles De Gennes Lecture Prize
This July, during the International Soft Matter Conference 2010 in Granada, Spain, Professor Sam Safran will give the EPJ E - Pierre Gilles De Gennes lecture, associated with a prize given by the publishers of EPJ.
This is the first edition of the *EPJE - Pierre-Gilles De Gennes Lecture Prize*, which takes the name from the illustrious Nobel laureate who founded EPJ E.
The Editors in Chief elected Prof. Sam Safran of the Weizman Instutite, Israel, as the prize recipient to acknowledge his leading research in soft matter and biological physics. The prize was also endorsed by the ISMC 2010 conference committee.
The prize will be presented to Prof. Sam Safram by Prof. Dominique Langevin (who is an Associate Editor of EPJ E) at the beginning of his plenary talk, 6 July at 8.30 am.
If you wish to vist the ISMC 2010 website go to http://ismc2010.ugr.es/

June 2010

EPJ D - Speed-control zone for polar molecules
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)

June 2010

EPJ B - Superfluidity of a perfect quantum crystal
Only one liquid exhibits Bose-Einstein condensation in nature: Helium II, . At such temperatures, all other substances are solid. In these two papers, Vitaly Golovko demonstrates that Bose-Einstein condensation can also occur in the solid state. Moreover, it is shown that at 0 K, a condensate crystal is energetically preferable with respect to the same quantum crystal without condensate. Therefore, on lowering the temperature of the crystal there must somewhere happen Bose-Einstein condensation, as in liquid helium. This opens a huge field for experimental investigations of Bose-Einstein condensation and of its influence on properties of solids.

Click here to view the full papers: [V. Golovko, Eur. Phys. J. B 71 1 (2009) 85-95] and [V. Golovko, Eur. Phys. J. B 74 3 (2010) 345-356]

May 2010

EPJ B - What atomistic methods tell us about the mechanical response of amorphous solids
Our understanding of elasticity, plasticity and failure in non-crystalline solids has greatly enhanced through atomic scale simulation. A new Colloquium paper In EPJ B reviews a variety of computational approaches that have been successful in elucidating the atomic scale phenomena that control the mechanics of amorphous solids. The constitutive theories that have been developed for describing mechanical response are briefly illustrated, as well as the prospects for testing the assumptions of these theories using simulation. The authors, M.L. Falk and C.E. Maloney, pose the most pressing open questions for substantiating these theoretical approaches, and ultimately for understanding and predicting the mechanical behaviour of amorphous solids.

To read the full paper "Simulating the mechanical response of amorphous solids using atomistic methods" by M.L. Falk and C.E. Maloney, European Physical Journal B click here.

May 2010

EPJ B - sp3 domains in graphite induced by visible light
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.

April 2010

Schrödinger Medal awarded to EPJ D Editor in Chief
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.

April 2010

EPJ D - Electrons go unperturbed in a matter-wave interferometer
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

April 2010

Quantum memories set to go a long way

A Raman memory
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

April 2010

Liquid crystals straighten up
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

March 2010

Giving light a good squeeze
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
Go to the EPJ D highlights page to read about two more recent highlights from the journal.

January 2010

Athene Donald wins Glamour award
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.

January 2010

Daan Frenkel becomes Editor in Chief of EPJ E
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.

January 2010

Nigel Mason becomes Editor in Chief of EPJ D
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.

December 2009

First proton–proton collisions at the LHC as observed with the ALICE detector
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

Fig. 1 shows the first pp collision candidate by the event display in the ALICE counting room (3D view).
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

December 2009

Atom interferometry in free flight
Philippe Bouyer and co-workers in France performed a range of impressive experiments with an atom interferometer in free flight, onboard an Airbus aircraft making "micro-gravity jumps". These experiments successfully demonstrate that when atoms are sufficiently cooled and controlled, their wave properties can be used to perform interferometry in a way analogous to standard interferometry with light. This moves the field closer to the implementation of a range of sensors for e.g. gravity, rotation and inertia with unprecedented accuracy. Such devices will be potentially very useful in satellites and in space missions.
To read the full paper by Philippe Bouyer et al. on "Light-pulse atom interferometry in microgravity" click here

November 2009

Tidal waves on liquid Helium-4
An analytical theory explains why a probe molecule such as Na₂ on the surface of a liquid ⁴He droplet creates soft vibrations which can be used to study the dynamics of the droplet surface with optical spectroscopy.
To read the full paper by Hizhnyakov, Tehver and Benedek click here

November 2009

Microscopic modeling of electronic quantum nanodevices reviewed in a Colloquium paper by D. Taj, R.C. Iotti and F. Rossi
Quantum devices represent an important topic of modern nanoscience, characterized by its multi-disciplinary flavor where condensed matter physics, quantum theory, and information technology merge into a unique body of knowledge. In this Colloquium paper Taj and co-workes review and discuss how to work out a microscopic modeling of state-of-the-art electronic quantum devices. The emphasis is on the description of energy-relaxation and decoherence phenomena. Finally, the authors propose an alternative formulation of the problem in terms of a generalized Fermi's Golden Rule. Click here to view the full text: [D. Taj et al., Eur. Phys. J. B 72 (2009)]

October 2009

The unusual electronic and transport properties of graphene-based nanostructures reviewed in a Colloqium paper by Dubois, Zanolli, Declerck, and Charlier in EPJ B
Graphene-based nanostructures are expected to display the extraordinary electronic, thermal and mechanical properties and are thus promising candidates for a wide range applications and opening alternatives to present silicon-based electronics devices. This paper reviews the electronic and quantum transport properties of these carbon nanomaterials in which confinement effects are playing a crucial role. After reviewing the transport properties of defect-free systems, doping and topological defects are also proposed as strategy to tailor quantum conductance in these materials.
For further information see [S.M.-M. Dubois et al., Eur. Phys. J. B 72/1 (2009)]

October 2009

Time stamping in Einstein-Podolsky-Rosen experiments
Using the time of detection of each single photon, the authors falsify a class of non-ergodic local models that have not been tested in previous experiments on the Bell inequality.
To read the full paper by M.B. Agüero, A.A. Hnilo, M.G. Kovalsky and M.A. Larotonda click here

July 2009

Kurt Becker to lead the plasma physics sections of EPJ D
As of July 2009 The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics has a third Editor-in-Chief. Kurt H. Becker (NYU-Poly) has been appointed and will work alongside Franco Gianturco and Claude Fabre, toward strengthening EPJ D. His particular emphasis will be on low-temperature plasma physics.
Kurt H. Becker is a Professor of Physics and the Associate Provost for Research and Technology Initiatives at Polytechnic Institute of New York University (NYU-Poly) in Brooklyn, NY. His background is in experimental atomic, chemical, and plasma/discharge physics. He has worked extensively on experimental and theoretical studies of electron-driven processes and on low-temperature plasma science and technology. Prior to joining NYU-Poly in 2007, he held faculty positions at Lehigh University, the City College of CUNY, and at Stevens Institute of Technology, where he was the Head of the Department of Physics and Engineering Physics and also Associate Director of the Center for Environmental Systems. Kurt Becker is a Fellow of the American Physical Society and holds an Honorary Degree from the Leopold Franzens University Innsbruck, Austria.
For further information read the Editorial of the EPJD topical issue on Plasma Science and Technology (August 2009) edited by Kurt Becker.

May 2009

EPJ launches EPJ Web of Conferences
an open-access publishing service dedicated to the publication of conference proceedings and the related archiving of conference web pages. Maximum speed of publication and visibility are combined with a maximum of flexibility regarding formats. For further information have a look at the website of
EPJ Web of Conferences

December 2008

As of January 2009 the subtitle of The European Physical Journal E will be Soft Matter and Biological Physics
The publishers of The European Physical Journal (EPJ) and the Editors-in-Chief are pleased to announce that the scope of the journal has substantially extended to include all aspects of the study of biological systems by physical approaches. The opening of EPJ E to cover the full spectrum of biological physics reflects the growing importance of this field, its strong conceptual and methodological links with soft matter physics, and gives biological physics a true home in the EPJ series.
With the appointment of Frank Jülicher as Editor-in-Chief, alongside Richard A.L. Jones and Georg Maret, the aims and scope of EPJ E have been expanded to include:

- Nucleic acids, membranes and proteins
- Single molecules and nanoscale molecular machines
- Cellular processes and multicellular systems
- Biomimetic systems
- Biological networks

November 2008

Athene Donald to receive a 2009 L'ORÉAL-UNESCO award
Athene Donald, Professor of Experimental Physics at the Cavendish Laboratory in Cambridge, has been nominated for her contribution to unravelling the mysteries of the physics of messy materials, ranging from cement to starch. Some of this work was published in the EPJ E. The former editor in chief of EPJ E (and current member of its advisory editorial board) will receive her prize on 5 March 2009, at UNESCO Headquarters in Paris. Since 1998, the L'ORÉAL-UNESCO Awards have distinguished 57 women from around the globe. Through their individual contributions to scientific research the Laureates have been agents for change and progress. We have no doubt that Athene Donald will take this award as a new opportunity to promote the work and dedication of female scientists and inspire them to excel.

November 2008

EPJ celebrates its 10th anniversary
Begun as a merger of Journal de Physique, Il Nuovo Cimento and Zeitschrift für Physik in 1998, EPJ presents itself today as a yet broader coalition and continuation of these founding journals plus Acta Physica Hungarica, Anales de Fisica, Czechoslovak Journal of Physics, and Portugaliae Physica. Consequently, EPJ is characterized by a rapidly growing author- and readership. Read the full article published in Europhysics News.

October 2008

EPJC further extends OA publishing scheme
Following the completion of the first period (2007-2008) of its OA publishing scheme, and in anticipation of successful negotiations with interested Open Access funding agencies in the future, the "open access" publishing fees for all experimental papers submitted to and accepted for publication by The European Physical Journal C - Particles and Fields will continue to be waived. The paper categories concerned are both regular articles and scientific notes, on experimental physics. Independently, all Letters continue to be published "open access" by default, without any fees being incurred by the authors. (see the complete EPJ Open Access Statement for more details)

September 2008

EPJ C appoints new theory Editor-in-Chief
Prof. Georg Weiglein (University of Durham, UK) has been appointed the new Editor-in-Chief for theoretical particle and high-energy physics of The European Physical Journal (EPJ) C. He leads the journal into the hot phase of LHC physics and works together with Prof. Siegfried Bethke (MPI Munich, Germany), Editor-in-Chief for experimental physics. Georg Weiglein succeeds Jochen Bartels (University of Hamburg, Germany), who had been the journal's theory Editor-in-Chief since 1999. Jochen Bartels and Dieter Haidt (DESY, Hamburg) together successfully shaped the profile of EPJC, after the merger of the famous journals Zeitschrift für Physik C and Il Nuovo Cimento A, back in 1998.

May 2008

EPJ B appoints new Editors-in-Chief
The publishers of The European Physical Journal B - Condensed Matter and Complex Systems are pleased to announce the appointment of Prof. Alois Loidl (U of Augsburg) and Prof. Luciano Colombo (U of Cagliari) as new Editors-in-Chief for experimental resp. theoretical condensed matter physics. At this occasion, EPJ B opens a new main section on computational methods which will publish papers on the theoretical development and numerical benchmarking of existing and new tools in scientific computing of relevance for computational solid state and materials physics. In particular, ab initio techniques, atomistic simulations, quantum monte carlo, and multiscale modelling will be in the new focus.

EPJ B, D, and E extend the publication of topical reviews (colloquium papers)
Colloquia describe the development of new areas of research or the impact of new and promising experimental, theoretical or computational methods in the fields that are within the spectrum of topics covered by the journal. While not as extensive and complete as reviews in the usual sense, they are intended to suitably introduce new research directions and techniques in their early stages of development, and to a wider audience. There is no explicit constraint regarding the length of such manuscripts, although 20 printed pages would be the most usual length. All invited/submitted manuscripts will undergo the same refereeing procedure as all other contributions submitted to the journal. For accepted colloquium papers, authors will receive a honorarium of EUR 200,-- and colour figures will be free of charge. For more details on this new section in EPJD see the Editorial written by the Editors-in-Chief Claude Fabre and Franco A. Gianturco.

November 2007

EPJ C extends OA publishing scheme
In anticipation of successful negotiations with interested Open Access funding agencies, as of today and until such negotiations have taken place before or by the end of 2008, all experimental papers submitted to and accepted by The European Physical Journal C - Particles and Fields will be published with full, online open access without any fees being incurred by the authors. The paper categories concerned are letters, regular articles as well as scientific notes and tools articles on experimental physics. (see the Aims & Scopes for a definition of these categories)

This extends the scope of the present default scheme for publishing with online open access in any of the EPJ journals at the strongly discounted price of EUR 1,000.-- per article, with letter articles already being free of charge and open access by default for EPJ A and EPJ C since November 2006 (see the Open Access Statement for more details)

September 2006
The publishing consortium of The European Physical Journal (EPJ) and the Editors-in-Chief are pleased to announce that The European Physical Journal B - Condensed Matter and Complex Systems has substantially extended its existing publishing activities in the fields of Statistical Physics and Nonlinear Dynamics to encompass all aspects of the emerging field of Complex Systems. With the appointment of Prof. Frank Schweitzer (Z&rich) as section editor for the newly created section Complex Systems within the Editorial Board of EPJ B, the aims and scopes of EPJ B have recently been enlarged to include:

Statistical and Nonlinear Physics Methods
Fluctuation phenomena and stochastic processes
Phase transitions and critical phenomena
Discrete dynamics, chaos and adaptive control
Time series analysis
Non-equilibrium dynamics, pattern formation
Physics of networks

Interdisciplinary Physics
Information theory, combinatorial optimization
Multi-agent systems, selforganization and emergence
Multicellular phenomena, systems biology
Ecological and population dynamics
Environmental systems, hazards and risks
Traffic, infrastructures and urban dynamics
Dynamics of groups and organizations
Economic models, evolutionary game theory
Financial markets, econophysics
Information, social and economic networks

The Editors-in-Chief of EPJ B
Prof. Hans-Rudolf Ott (Z&rich), Prof. Petra Rudolf (Groningen)
The EPJ publishing consortium

August 2006
EPJ A broadens its scope in heavy ion physics by merging with the Acta Physica Hungarica A - Heavy Ion Physics (APH A) as of January 1st, 2007. APH A, a well respected journal in the field has emerged from the Acta Physics Hungarica, initially covering all areas of physics, in the 1990s. See also the Letter of the Editor of APH

August 2006
EPJ D broadens its scope in plasma physics by merging with the Czechoslovak Journal of Physics (CJoP) as of January 1st, 2007. CJoP is presently published by the Institute of Physics of the Czech Academy of Sciences and distributed by Springer. Publishing in all areas of physics CJoP is particularly active in the field of plasma physics. To reflect this new emphasis in scope, EPJ D has recently changed its subtitle from "Atomic, Molecular and Optical Physics" to "Atomic, Molecular, Optical and Plasma Physics". Acta Physica Hungarica B - Quantum Electronics is also merging. See also the Letter of the Editors of EPJ D

October 2005
EPJ D supports and endorses the European Commission's new Quantum Information Classification Scheme (QICS) which, in the field of quantum information sciences, both extends and complements the well-known PACS scheme. For accepted EPJ D articles relevant to the subject matter, the Editorial Office of EPJ D will kindly invite authors to provide appropriate QICS codes in addition to the usual PACS codes. See also the Press Release. The HTML version of the QICS codes can be found here.

March 2005
Dr Dominique Langevin, University of Paris-Sud, Orsay, France Associate Editor EPJ E-Soft Matter, has been awarded the L'ORAL-UNESCO Award 2005 Materials Sciences for her fundamental investigations of detergents, emulsions and foams.
Press Release

News

EPJ C - "Spooky action at distance" in particle physics?!

Physicists have developed the first conclusive test to better understand high-energy particles correlations.

EPJE - How to build doughnuts with Lego blocks

Controlling forces between oppositely charged polymers opens a new route towards creating vectors for gene therapy

EPJB - New model for epidemic contagion

Improved estimates on the geographical spread of infectious diseases are achieved by studying human mobility networks

EPJB - Towards high-temperature superconductors

Scientists produce a new type of superconductor by manipulating graphene, the study of which led to a Nobel Prize

EPJA - Vector Correlators in Lattice QCD: Methods and Applications

EPJD - Largest ever gas mix caught in ultra-freeze trap

Towards a better understanding of subatomic particles using a new cold-atom setup

EPJB - Random noise helps make signals clearer

Model shows that signal clarity only improves if specific energy conditions are met

EPJE - The art of stabilising entangled spaghetti-like materials

Controlling forces between oppositely charged polymers opens a new route towards creating vectors for gene therapy

EPJD - Instant nanodots grow on silicon to form sensing array

New methods for creating 3D nanostructures deposited on an array of regularly spaced indentations on the surface of silicon films opens the door for innovative nanosensors

EPJB - No extraordinary effects from microwave and mobile phone heating

Study quantifies effects of electric field-induced versus conventional heating

EPJ C - New Theory Editors-in-Chief and Fermi Prize for Dieter Haidt

EPJB - Can metals remember their shape at nanoscale, too?

How nickel-titanium nanometric-size particles change back to their memorised shape

EPJD - Not one, not two, not three, but four clones!

First quantum cloning machine to produce four copies

EPJE - How biological capsules respond under stress

Innovative high-precision measuring tool to assess the bending elasticity of liposomes

EPJ E - How do protein binding sites stay dry in water?

EPJ E - What makes tires grip the road on a rainy day?

Scientists examine the flow of liquid at the contact between randomly rough surfaces

EPJ A - The Similarity Renormalization Group for Three-Body Interactions in One Dimension

EPJ C - No sign of supersymmetry

Most stringent limits ever set by ATLAS

EPJ E - Unlocking jams in fluid materials

A new theoretical model which helps to understand how to best avoid jamming of soft matter.

EPJ D - Quantum teleportation analysed by mathematical separation tool

Scientists from the University of Vienna’s Faculty of Physics in Austria recently gave a theoretical description of teleportation phenomena in sub-atomic scale physical systems, in a publication in the European Physical Journal D.

EPJ E - New complex offers potentially safer alternative for gene therapy delivery

Spontaneous ordering of DNA fragments in a special matrix holds the key to creating non-toxic gene therapy delivery vectors, according to a study recently published in the European Physical Journal E.

EPJ Plus - The twin paradox in a cosmological context

The twin paradox has been a source of debate since it was discovered by Einstein. It can be analytically verified assuming the existence of global nonrotating inertial frames.

EPJ Plus - Discovering Technicolor

EPJ B – Online activity grows in a similar pattern to those of real-life networks

The activity of online communities does not grow in line with the number of users, according to a model recently published in the European Physical Journal B.

EPJB - Atomistic details over longer time scales

The conventional method for atomistic simulation, namely molecular dynamics (MD), is not well suited to resolve slow dynamical processes, that is processes associated with a system that gets trapped from time to time in deep local energy minima.

EPJ E - Embryo development obeys the laws of hydrodynamics

The law of hydrodynamics can contribute to our understanding of how a cluster of embryonic cells can transform into an animal within the first 36 hours of development, according to research recently published in European Physical Journal E.

EPJB - Disordered networks synchronise faster than small world networks

A study recently published in European Physical Journal B presents observations of how complex systems synchronise over time.

EPJ Plus – New analytic method to solve 2-d Helmholtz equation for irregular boundaries

EPJ Plus – Focus on Hadron Therapy in Europe

EPJ Impact Factors on the rise

EPJE - Compare Motor Models: Two-State versus Crossbridge

EPJ B welcomes a new Editor-in-Chief for its complex systems section

EPJ B - Deciphering complex games

EPJ Plus – Alternative Electroweak Model without a Higgs

EPJD - Speedier Quantum Logic

EPJB – Round-up on the conductivity of carbon nanomaterials

Jean Daillant nominated new Director General of SOLEIL

EPJB – New theory predicts dispersion in porous solids

EPJ H - Cosmic Rays: a (partly) untold story

EPJD - 'Measurement of Quantum Mechanical Operators' Revisited

EPJ D - Feshbach resonances in the 6Li-40K Fermi-Fermi mixture: Elastic versus inelastic interactions

EPJ D – Nanodroplets make perfect hosts

EPJ E - Pierre Gilles De Gennes Prize awarded to Michael E. Cates

EPJ E - Polymersomes made-to-measure

EPJ B - Solids under pressure

EPJ E – Simple routes to surface-attached polymer layers

EPJ E - Gems for polymer scientists

EPJ B - Geometry matters

EPJ A – Validating Aspects of the Strong-Coupling Regime of QCD

EPJ Plus publishes first Focus Point - Major Advances in HEP Software

EPJ B - Complexity Theory and the National Baseball Hall of Fame

Jean-Marc Di Meglio becomes Editor in Chief of EPJ E

EPJ D - Reshaping Quantum Light

EPJ B – Au and Cu as building blocks of high-density memory devices

EPJ E - How the fruit fly got its spots

EPJ to announce Open Access plans in the course of 2011

Kari Dalnoki-Veress wins Rutherford Memorial Medal

EPJ D - Feshbach resonances in the ⁶Li-⁴⁰K Fermi-Fermi mixture: Elastic versus inelastic interactions