The European Physical Journal (EPJ) is a series of peer-reviewed journals covering the whole spectrum of physics and related interdisciplinary subjects. EPJ is committed to high scientific quality in publishing and is indexed in all main citation databases.
Physicists reveal that the real-time dynamics in a football game are subject to self-similarity characteristics in keeping with the laws of physics, regardless of players’ psychology and training
Football fascinates millions of fans, all of them unaware that the game is subject to the laws of physics. Despite their seemingly arbitrary decisions, each player obeys certain rules, as they constantly adjust their positions in relation to their teammates, opponents, the ball and the goal. A team of Japanese scientists has now analysed the time-dependent fluctuation of both the ball and all players’ positions throughout an entire match. They discovered that a simple rule governs the complex dynamics of the ball and the team’s front-line. These findings , published in EPJ B, could have implications for other ball games, providing a new perspective on sports science.
The effect of spatial ordering of molecules on surfaces is commonly utilised to deposit ultra-thin films, where the film thickness is only a few nanometres. In this EPJ D review paper, several methods are discussed that are distinguished from other thin film deposition processes by exactly these effects, leading to self-assembling and self-limiting layer growth and, eventually, to coatings with unique and fascinating properties, and applications in micro-electronics, optics, chemistry, and biology.
Italian physicist Carlo Di Castro shares his thoughts on the development of theoretical condensed matter physics in Rome from the 1960s until the beginning of this century.
Italian physicist Carlo Di Castro, professor emeritus at the University of Rome Sapienza, Italy, shares his recollections of how theoretical condensed matter physics developed in Rome, starting in the 1960s. Luisa Bonolis, a researcher at the Max Planck Institute for the History of Science in Berlin, Germany invited Di Castro to reflect upon his research career, which he did in an interview published in EPJ H.
In this unique document, Di Castro talks about his upbringing during the second World War. He also explains how this childhood experience later influenced his philosophy, which he aptly summarises as follows: “the fear of the unknown must be overcome through knowledge and reason.” Ultimately, this approach guided the career choices that led him to become a condensed matter physicist.
A new study represents a step forward in our understanding of the nature of exchange interactions between identical particles, which only occur at the quantum level
Two-particle interference has been the focus of many studies, specifically in quantum optics with photons. However, interference between two massive, identical particles is not so well understood. In a study published in EPJ D, Pedro Sancho from the CLPU—Centre for Pulsed Lasers—in Salamanca, Spain, uncovers a counterintuitive result whereby particles called bosons do not behave as expected—they are overlapping, and not interfering—due to the combination of interference and so-called exchange interaction. The latter is a quantum mechanical effect that alters their symmetry when identical particles are exchanged.
Physicists use carbon dating to confirm alleged Fernand Léger painting was definitely a fake, thus corroborating the doubts about its authenticity previously expressed by art historians
Choosing the right physical technique to analyse paintings can make all the difference when it comes to ascertaining their authenticity. Now, a painting initially attributed as belonging to a series called ‘Contraste de formes’ by French Cubist painter Fernand Léger has definitely been identified as a forgery. This is the first time it has been possible to identify a fake painting by relying on the anomalous behaviour of the concentration of the radioactive form of carbon (14C) in the atmosphere after 1955 to date the canvas. These findings were recently published in EPJ Plus by Mariaelenea Fedi of the National Institute of Nuclear Physics (INFN) in Florence, Italy, and colleagues.
A new study focuses on the feasibility of scaling up renewable energy to cover the needs of a country the size of Germany
Can renewable energy adequately supply the power grid, despite its intermittent nature? This is the key question in a new study published in EPJ Plus. The study is based on an analysis of concrete data from 2012 for the German national grid, which also utilises electricity from both on and offshore wind (8%) and solar sources (4.8%). Friedrich Wagner from the Max-Planck Institute for Plasma Physics in Greifswald, Germany, outlines the key issues associated with the use of renewable energy on a large scale.
To understand natural phenomena with a chaotic nature, the key is to find out how their variable physical characteristics behave at the very point preceding the onset of chaos
The edge of chaos—right before chaos sets in—is a unique place. It is found in many dynamical systems that cross the boundary between a well-behaved dynamics and a chaotic one. Now, physicists have shown that the distribution—or frequency of occurrence—of the variables constituting the physical characteristics of such systems at the edge of chaos has a very different shape than previously reported distributions. The results have been published in EPJ B by Miguel Angel Fuentes from the
Santa Fe Institute in New Mexico, USA, and Universidad del Desarrollo, Chile, and Alberto Robledo from the National Autonomous University of Mexico, Mexico City. This could help us better understand natural phenomena with a chaotic nature.
Ensuring that parents in recomposed families see their children regularly is a complex network problem that models developed to study materials may help to solve
Physics can provide insights into societal trends. Problems involving interactions between people linked in real-life networks can be better understood by using physical models. As a diversion from his normal duties as a theoretical physicist, Andrés Gomberoff from the Andres Bello University, in Santiago, Chile, set out to resolve one of his real-life problems: finding a suitable weekend for both partners in his recomposed family to see all their children at the same time. He then joined forces with a mathematician and a complex systems expert. This resulted in a study published in EPJ B, showing that solving this problem essentially equates to minimising the energy in a material model.
New insights into Einstein’s view of the cosmos from the translation and study of one of his least known papers
A paper published in EPJ H provides the first English translation and an analysis of one of Albert Einstein’s little-known papers, “On the cosmological problem of the general theory of relativity”. Published in 1931, it features a forgotten model of the universe, while refuting Einstein’s own earlier static model of 1917. In this paper, Einstein introduces a cosmic model in which the universe undergoes an expansion followed by a contraction. This interpretation contrasts with the monotonically expanding universe of the widely known Einstein-de Sitter model of 1932.
Albert Einstein accepted the modern cosmological view that the universe is expanding, only long after several of his contemporaries had demonstrated it with astrophysical observations
Until 1931, physicist Albert Einstein believed that the universe was static. An urban legend attributes this change of perspective to when American astronomer Edwin Hubble showed Einstein his observations of redshift in the light emitted by far away nebulae—today known as galaxies. But the reality is more complex. The change in Einstein’s viewpoint, in fact, resulted from a tortuous thought process. Now, in an article published in EPJ H, Harry Nussbaumer from the Institute of Astronomy at ETH Zurich, Switzerland, explains how Einstein changed his mind following many encounters with some of the most influential astrophysicists of his generation.
MINOS is a new apparatus dedicated to in-beam nuclear structure experiments with low-intensity exotic beams at energies above 150 MeV/nucleon.
It is intended to provide increased luminosity compared to standard solid-target experiments in hydrogen-induced studies, while simultaneously improving experimental resolution. This article exposes the concept of the device developed at the CEA in France and reviews in detail the associated recent technical advances. MINOS is composed of a thick finger-shaped liquid hydrogen target, from 50 to 200 mm thick, combined with a compact time projection chamber serving as a vertex tracker, the first of its kind in low-energy nuclear physics. This innovative setup offers access to the first spectroscopy of a new range of very exotic nuclei beyond our current reach. An exciting program on the search for new 21+ states in neutron-rich even-even nuclei, spectroscopy of unbound oxygen nuclei and di-neutron correlations in borromean nuclei will be performed with MINOS at the RIKEN Radioactive Isotope Beam Factory in Japan over the next few years. MINOS is funded by the European Research Council.
A new study proposes a method for quantitatively analysing the relative value of models for crowd dynamics prediction, following individual movement
Stampedes unfortunately occur on too regular a basis. Previously, physicists developed numerous models of crowd evacuation dynamics. Their analyses focused on disasters such as the yearly Muslim Hajj or of the Love Parade disaster in Germany in 2010. Unfortunately, the casualties at these events may have been linked to the limitations of the crowd dynamics models used at the time. Now, a new study outlines a procedure for quantitatively comparing different crowd models, which also helps to compare these models with real-world data. In a paper published in EPJ B, Vaisagh Viswanathan, a PhD student from Nanyang Technological University in Singapore, and colleagues have demonstrated that these crowd evacuation dynamics models are a viable decision-making tool in safety preparation and planning concerning real-world human crowds.
The publishers are pleased to announce the launch of a new open-access journal in the EPJ series – EPJ Quantum Technology. The journal has just gone live, with three research papers already available.
Driven by advances in technology and experimental capability, the last decade has seen the emergence of quantum technology: a new praxis for controlling the quantum world. It is now possible to engineer complex, multi-component systems that merge the once distinct fields of quantum optics and condensed matter physics.
The inner structure of soft adhesive materials during the debonding process is, for the first time, under scrutiny in the hope of producing new, improved adhesives in the future
Tape, self-adhesive labels, Post-it notes and masking tape all contain soft adhesives. This makes them easy to remove—a process referred to as debonding. French scientists have studied how soft adhesives work in the hope of facilitating the design of more efficient adhesives. Francois Tanguy, a researcher at ESPCI ParisTech, the School of Industrial Physics and Chemistry, in Paris, France, and colleagues have, for the first time, performed a precise analysis of the material deformation and structure during the course of debonding for several model adhesives. Their findings are published in EPJ E. By better understanding the connection between the energy dissipated by the polymeric material with adhesive qualities and its response to traction, they hope to improve models of adhesive performance.
The theory of interstitialcy for simple condensed matters is a theory formulated by Andrew V. Granato enable the determination of the thermodynamic and kinetic properties of simple liquids and glasses. In a new Colloquium in EPJ B the author provides a simpler, more physical and compelling version of his interstitialcy theory. In addition, the results of computer simulations, together with direct and indirect experimental evidence, are updated and reviewed. In addition, the results of computer simulations, together with direct and indirect experimental evidence, are updated and reviewed. The connection between theory and experiment for some of the more notable properties of simple condensed matter is discussed. The direct visual observation of interstitial diffusion to the surface of irradiated platinum thin films near 20K by Morgenstern, Michely and Comsa provides compelling evidence for the interstitialcy theory presented herein.
Equations used to describe parallel worlds in particle physics can help study the behaviour of particles in parallel graphene layers
Belgian scientists have used a particle physics theory to describe the behaviour of particle-like entities, referred to as excitons, in two layers of graphene, a one-carbon-atom-thick honeycomb crystal. In a paper recently published in EPJ B, Michael Sarrazin from the University of Namur, and Fabrice Petit from the Belgian Ceramic Research Centre in Mons, studied the behaviour of excitons in a bilayer of graphene through an analogy with excitons evolving in two abstract parallel worlds, described with equations typically used in high-energy particle physics.
As of January 2014, The European Physical Journal C – Particles and Fields will be published as full open access journal funded by SCOAP3. One of the leading journals in the field, EPJ C was selected to participate in this initiative - lead by CERN with the support of partners in 24 countries - which will make a vast fraction of scientific articles in the field of High-Energy Physics open access at no cost for any author. Moreover authors will retain copyright and creative commons licenses will enable wide re-use of the published material.
A new study focuses on the motion of motor proteins in living cells, applying a physicist’s tool called non-equilibrium statistical mechanics
Motion fascinates physicists. It becomes even more intriguing when observed in vivo in biological cells. Using an ingenious setup, Japanese scientists have now calculated the force of molecular motors acting on inner components of biological cells, known as organelles. In this study, the focus is on mitochondria—akin to micrometric range cellular power plants—travelling along microtubules in a cell. Published in EPJ E by Kumiko Hayashi, from Tohoku University, Sendai, Japan, these findings could contribute to elucidating the transport mechanism in biological cells by multiple motors.
A new study focused on electric discharge behaviour under intense gravitational forces shows that its dynamic changes as gravity increases
Arc discharges are common in everyday conditions like welding or in lightning storms. But in altered gravity, not as much is known about the behaviour of electric discharges. For the first time, Jiří Šperka from Masaryk University, Czech Republic, and his Dutch colleagues studied the behaviour of a special type of arc discharge, so-called glide arc, in varying hypergravity conditions, up to 18 G. In a paper just published in EPJ D, they demonstrate how the plasma channel of this glide arc discharge moves due to external forces of buoyancy in varying gravity conditions. These results could have implications for improved safety precautions in manned space flights, and in the design of ion thrusters used for spacecraft propulsion.
A new Colloquium in EPJE by Xiao-Jing Zheng introduces and reviews the fundamental laws of the electrification of wind-blown sand and their influence, and highlights the challenges in this field.
The electrification of wind-blown sand is a typical complex system characterised by nonlinearity, randomness, multi-field coupling between thermal diffusion, E-fields and sand movements, as well as trans-scale processes with multi-phase media. Owing to the complex mechanism and the influence of the electrification of wind-blown sand , a number of issues remain poorly understood. These include: (1) why sand particles get charged during wind-blown sand movements; (2) how many electric charges a sand particle acquires; (3) why the electric polarity of sand particles is related to the particles’ size; (4) what the change law of wind-blown sand E-fields is, and (5) how to predict the intensity and influence of wind-blown sand E-fields.
A new protocol, exploiting the quantum properties of materials, makes it possible to improve the accuracy of photolithography by addressing its physical limitations due to diffraction
Photolithography uses light beams to design thin geometric patterns on the substrates of semiconductors used in microelectronic devices. This is achieved using a chemical reaction on a light-sensitive chemical, called photoresist. The trouble is that the phenomenon of light diffraction does not permit highly accurate patterns. Often, the edges of stripes have low contrast, the distances between the stripes and the stripes’ width are limited by what is referred to as Rayleigh’s diffraction limit. Now, a scientist from Russia has developed a quantum lithography protocol designed to improve the resolution of this technology. The findings of George Miroshnichenko, a physicist at Saint-Petersburg National Research University of Information Technologies, Mechanics and Optics, in Russia, have just been published in EPJ D.
The alleged shortcomings of quantum theory do not hold up to scrutiny, as the theory proves sound for the prediction of probability of events connected to the fate of sub-atomic scale particles
A colloquium paper published in EPJ D peers into the alleged issues associated with quantum theory. Berthold-Georg Englert from the National University of Singapore reviews a selection of the potential problems of the theory. In particular, he looks into cases when mathematical tools are confused with the actual observed sub-atomic scale phenomena they are describing. Such tools are essential to provide an interpretation of the observations, but cannot be confused with the actual object of studies.
A new study demonstrates that electrical resistivity obeys a staircase-like dependence on the conducting particle concentration in composite materials
Composite materials are of increasing interest to physicists. Typically, they are made of electrically conducting elements - such as spherical metallic or elongated carbon particles - embedded in an insulating glass or a polymer matrix. Their controllable electrical resistivity combined with their light and flexible properties, makes them suited for applications in flexible electronics. Now, a theoretical model, confirmed experimentally, elucidates how electrical resistivity varies with the concentration of the particles in these composite materials. These findings have been published in EPJ B, by Isaac Balberg and colleagues from the Hebrew University in Jerusalem, Israel.
New calculations shows that the influence of quantum effects on the operating conditions of nanodevices has, until now, been overestimated
Micro- and nano-electromechanical devices, referred to as MEMS and NEMS, are ubiquitous. These nanoscale machines with movable parts are used, for example, to trigger cars’ airbags following a shock. They can also be found in smartphones, allowing them to detect how to adequately display the screen for the viewer. The trouble is that, as their size decreases, forces typically experienced at the quantum level start to matter in these nanodevices. Mexican physicists have studied the mechanical and electrical stability of MEMS and NEMS, depending on the plate thickness and the nature of the material used. The results have now been published in EPJ B by Raul Esquivel-Sirvent and Rafael Perez-Pascual from the National Autonomous University of Mexico, in Mexico City.
No better solution to studying ever-draining foams than applying a strong magnetic field to keep the liquid in the foam at a standstill by levitating its water molecules
Foams fascinate, partly due to their short lifespan. Foams change as fluid drains out of their structure over time. It is precisely their ephemeral nature which has, until now, prevented scientists from experimentally probing their characteristic dynamics further. Instead, foams have often been studied theoretically. Now, Nathan Isert from the University of Konstanz, Germany and colleagues, have devised a method of keeping foams in shape using a magnet, which allows their dynamics to be investigated experimentally, as recently described in EPJ E.
Numerical simulations designed to confirm the magnetic characteristics of 3D quantum materials largely match the theoretical predictions
A new study set out to use numerical simulations to validate previous theoretical predictions describing materials exhibiting so-called antiferromagneting characteristics. A recently discovered theory shows that the ordering temperature depends on two factors—namely the spin-wave velocity and the staggered magnetisation. The results, largely consistent with these theoretical predictions, have now been published in a paper in EPJ B by Ming-Tso Kao and Fu-Jiun Jiang from the National Taiwan Normal University, in Taipei.
First study to shows specific sounds’ speed and attenuation characteristics in liquid foam, opens the door to new type of sound proofing material
Liquid foams fascinate toddlers singing in a bubble bath. Physicists, too, have an interest in their acoustical properties. Borrowing from both porous material and foam science, Juliette Pierre from the Paris Diderot University, Paris, France and her colleagues studied liquid foams. They used an impedance tube to measure the velocity and attenuation of acoustic waves in liquid foams in a broad frequency range. The study published in EPJ E is a first in the literature. It could help in assessing any liquid foam’s bubble size or in designing the optimal foam structure for sound proofing.
Fusion is one of the holy grails of energy production. Now, theoretical physicists have used simulations to investigate the uniformity of irradiation at the ignition stage of thermonuclear fusion reaction.
One of the ways to achieve thermonuclear fusion is through a controlled reaction between two light variants of hydrogen, called deuterium and tritium. Mauro Temporal, from the École Normale Supérieure Cachan, in France, and colleagues have made theoretical calculations indicating how best to improve the ignition stage of fusion reaction. Their approach, described in a paper published in EPJ D, involves increasing the uniformity of irradiation using high-power laser beams on the external shell of a spherical capsule containing a mix of deuterium and tritium.
How fluid dynamics and transport shaped the structure of our lungs in the course of evolution.
Two French physicists, Bernard Sapoval and Marcel Filoche from École Polytechnique in Palaiseau, France, suggest in a study published in EPJ E how evolution has shaped our lungs through successive optimisations of physical parameters such as conservation of energy and speed of delivery.
This EPJ B Colloquium presents an overview of the preparation method and physical properties of a new hybrid system consisting of single-walled carbon nanotubes (SWNTs) wrapped in conjugated polymers. The technique, which was first demonstrated in 2007, has attracted great interest owing to the high purity of the resulting semiconducting SWNTs and the possibility of applying them in electronic devices. Here, the authors review recent progress in the preparation of these nano-hybrids, their photophysical properties, and their applications in field-effect transistors and photovoltaic devices.