2017 Impact factor 1.536
Condensed Matter and Complex Systems


EPJ A Highlight - Lattice Improvement in Lattice Effective Field Theory

The dimer-boson inverse scattering length $1/a_{3}$ versus lattice spacing at LO, NLO, and N2LO. The vertical lines give the upper limits of the fit range

Lattice calculations using the framework of effective field theory have been applied to a wide range of few-body and many-body systems. One of the challenges of these calculations is to remove systematic errors arising from the nonzero lattice spacing. While the lattice improvement program pioneered by Symanzik provides a formalism for doing this and has already been utilized in lattice effective field theory calculations, the effectiveness of the improvement program has not been systematically benchmarked.

In this work lattice improvement is used to remove lattice errors for a one-dimensional system of bosons with zero-range interactions. To this aim the improved lattice action up to next-to-next-to-leading order is constructed and it is verified that the remaining errors scale as the fourth power of the lattice spacing for observables involving as many as five particles. These results provide a guide for increasing the accuracy of future calculations in lattice effective field theory with improved lattice actions.


EPJ C - New Editor-in-Chief for Experimental Physics I: Accelerator Based High-Energy Physics

Günther Dissertori (© Hostettler DPHYS/ETHZ)

The publishers of The European Physical Journal C – Particles and Fields are pleased to announce the appointment of Professor Günther Dissertori as new Editor-in-Chief for Experimental Physics I: Accelerator Based High-Energy Physics, replacing Professor Jos Engelen as of 1 January 2019.

Günther Dissertori obtained his PhD in Physics for a thesis on theoretical studies and experimental data analyses related to the ALEPH experiment at the CERN electron-positron collider LEP. He is Full Professor and Head of the Institute for Particle Physics and Astrophysics at ETH Zürich. Currently, the main focus of his research group is on the analysis of data taken with the CMS detector and its future upgrade, as well as on applications of particle physics detector technologies to bio-medical imaging, in particular positron emission tomography.

EPJ Plus Highlight - 3D virtual slicing of an antique violin reveals ancient varnishing methods

Volume rendering of the wood with the coating system on it.

Physicists and chemists use 3D scanning to unlock the forgotten secrets of the multi-layered coating methods that give violins their exceptional tone and look

Italian violin-making masters of the distant past developed varnishing techniques that lent their instruments both an excellent musical tone and impressive appearance. Few records from this era have survived, as techniques were most often passed down orally to apprentices; only scarce information is available on the original methods used for finishing the instruments. In a new study published in EPJ Plus, Giacomo Fiocco, affiliated with both Pavia and Torino Universities in Italy, and his colleagues use the synchrotron facility in Trieste to develop a non-invasive 3D-scanning approach that yields insights into the main morphological features of the overlapping finishing layers used on violins. In turn, the morphological images can be used to determine the chemical nature of the coating. This newly developed method could help scientists rediscover the procedures and materials used, and reproduce the multi-layered coating methods of the ancient masters.


20 Years of EPJ

EPJ 20th anniversary logo

This year has seen the 20th anniversary of the founding of EPJ, the European Physical Journal. We would like to thank all our editors, authors, referees and readers for contributing to EPJ’s success.

Merry Christmas and Happy New Year!
The EPJ Publishers

EPJ H Highlight - The coming of age of plasma physics

Plasma. Photo by Hal Gatewood on Unsplash

The story of the generation of physicists involved in the development of a sustainable energy source, controlled fusion, using a method called magnetic confinement

Once upon a time, people thought that electrons and ions always stuck together, living happily ever after. However, under low density of matter or high temperatures, the components of matter are no longer bound together. Instead, they form plasma, a state of matter naturally occurring in our universe, which has since been harnessed for everyday applications such as TV screens, chip etching and torches, but also propulsion and even sustained energy production via controlled fusion.

In a fascinating editorial for a special plasma issue of EPJ H, called “Plasma physics in the 20th century as told by players”, three physicists share their perspectives on key events in the early history of plasma physics, in the first half of the 20th century. First, Patrick Diamond, from the University of California San Diego, USA, shares his recollections of the early days of wireless transmission and the description of the ‘Heavyside Layer’ (the electrically conducting layer of the upper atmosphere, which transmits radio waves). In turn, Yves Pomeau from the Ecole Polytechnique in Palaiseau, France, talks about the role of Irving Langmuir in the development of plasma physics theory, namely his calculation of the frequency of oscillation of electrons in a plasma environment with much heavier ions. Lastly, Uriel Frisch from the University Cote D’Azur in Nice, France, describes the birth of nuclear fusion theory.


EPJ B Highlight - Holey graphene as Holy Grail alternative to silicon chips

Total magnetic moments of triangular holes in graphene.

Novel spintronics applications could stem from introducing holes into graphene to form triangular antidot lattices, granting the material new magnetic properties

Graphene, in its regular form, does not offer an alternative to silicon chips for applications in nanoelectronics. It is known for its energy band structure, which leaves no energy gap and no magnetic effects. Graphene antidot lattices, however, are a new type of graphene device that contain a periodic array of holes - missing several atoms in the otherwise regular single layer of carbon atoms. This causes an energy band gap to open up around the baseline energy level of the material, effectively turning graphene into a semiconductor. In a new study published in EPJ B, Iranian physicists investigate the effect of antidot size on the electronic structure and magnetic properties of triangular antidots in graphene. Zahra Talebi Esfahani from Payame Noor University in Tehran, Iran, and colleagues have confirmed the existence of a band gap opening in such antidot graphene lattices, which depends on the electron’s spin degree of freedom, and which could be exploited for applications like spin transistors. The authors perform simulations using holes that are shaped like right and equilateral triangles, to explore the effects of both the armchair-shaped and zigzag-shaped edges of graphene holes on the material’s characteristics.


EPJ B Highlight - Preventing concrete bridges from falling apart

Cement bridges can be degraded by environmental factors. Photo by Simone Hutsch on Unsplash

Concrete degradation from sulfuric acid can be avoided by finding ways of preventing its gas precursor from adsorbing into concrete

Extremes of temperature, rain, exposure to corrosive substances - all of these environmental factors contribute to the degradation of concrete. Specifically, a gas present in our environment, called hydrogen sulphide, turns into sulphuric acid, a corrosive substance, when combined with rainwater. In a new study published in EPJ B, Matthew Lasich from Mangosuthu University of Technology, Durban, South Africa, examines the adverse consequences of the adsorption of natural gas constituents found in our environment - and mixtures of several such gases -into one of the materials that make up concrete: cement hydrate. Lasich found that the preservation of concrete infrastructure from the corrosive effects would require a pre-treatment targeting the adsorption sites in cement hydrate, where the majority of hydrogen sulphide molecules become attached. However, this approach could prove difficult because of their wide distribution.


EPJ Plus Focus Point on New Technologies Related to Intentional and Accidental Release of CBRNe Agents

Since the events of September 11th 2001 and the anthrax attacks in America of the following month the general consensus is that there is a realistic possibility of some form of unconventional terrorist attack in the western world and that this could involve CBRN material [i.e., Chemical, Biological, Radioactive, Nuclear and explosive events]. It is therefore vital that local authorities and agencies operating in the National and International frameworks are prepared to respond, as effectively and efficiently as possible, to any crisis scenarios resulting from such non-conventional events.

This focus point collects some innovative tech solutions presented during the first international conference on CBRNe - SICC 2017, a conference devoted to promoting the dissemination of the different methodologies, techniques, theories, strategies, technologies and best practices on the prevention and mitigation of CBRNE risks. The conference intended to propose new solutions to reduce the risk factors related to CBRNe events and to promote the fruitful inter-professional collaborations between university and military/public experts, specialized operators, decision makers and the industry.


EPJ E Highlight - Sac with spiral surface patterns facilitate substance delivery through biological membranes

Introducing bend in the liquid crystal layers.

Faceted microfilms made up of liquid crystals arranged in spiral patterns can help squeeze through membranes and deliver helpful molecules

Imagine a micron-sized ball of fluid enclosed in a thin film, similar to the film in soap bubbles, but made up of molecules resembling liquid crystal. These molecules can lower their overall energy by aligning their directions with their ever-changing neighbours—a state referred to as smectic phase. This means stacks of parallel stripe-like liquid-crystal layers form in the film. In a new study published in EPJ E, Francesco Serafin, affiliated with both Syracuse University, New York, and the Kavli Institute for Theoretical Physics (KITP) at UCSB, USA, together with his advisor Mark Bowick, also at the KITP, and Sid Nagel, from the University of Chicago, IL,USA, map out all the possible smectic patterns of such spherical films, or sac, at zero temperature. They determine the conditions under which it becomes easier for such sacs to pass through biological membranes and, potentially, deliver molecules attached to them at specific locations.


EPJ Plus Highlight - On the trail of the Higgs Boson

Post-LHC collision showing how the particles decay.

The elusive particle won't share all the secrets of its creation mechanism at once

For the physics community, the discovery of new particles like the Higgs Boson has paved the way for a host of exciting potential experiments. Yet, when it comes to such an elusive particle as the Higgs Boson, it's not easy to unlock the secrets of the mechanism that led to its creation. The experiments designed to detect the Higgs Boson involve colliding particles with sufficiently high energy head-on after accelerating them in the Large Hadron Collider (LHC) at CERN in Geneva, Switzerland. In a quest to understand the production mechanisms for the Higgs Boson, Silvia Biondi from the National Institute of Nuclear Physics, Bologna, Italy investigated the traces of a rare process, called ttH, in which the Higgs Boson is produced in association with a pair of elementary particles referred to as top quarks. Her findings can be found in a recent study published in EPJ Plus. Future LHC experiments are expected to yield even more precise measurements of the Higgs Boson's ability to couple with particles that physicists are already familiar with.


Acting EiC: Wenhui Duan

Executive Editors:
B.K. Chakrabarti, W. Duan, E. Hernandez, H. Rieger
I am naturally indebted to you and the referees who contributed to this success with your time and constructive advice.

Hamid Assadi

ISSN (Print Edition): 1434-6028
ISSN (Electronic Edition): 1434-6036

© EDP Sciences, Società Italiana di Fisica and Springer-Verlag