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Condensed Matter and Complex Systems

News / Highlights / Colloquia

EPJ B Colloquium - Tensor network theory

Entropy of a 1d MERA: the number of links to cut in order to disconnect the L physical indices in the block form the rest of the system grows logarithmically with L, hence S(L) = O(log L). This is an example of an area-law in holographic space.

Tensor Network (TN) states are a new language, based on entanglement, for quantum many-body states. Román Orús, in a new EPJ B Colloquium, reviews four theoretical developments in TN states for strongly correlated systems.

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EPJ B Highlight - Taming neural excitations

Spatio-temporal plots of complex space time patterns in excitable media. © C. Bachmair et al.

A theoretical study of short- and long-range effects on neural excitation pulses might one day lead to controlling harmful signals such as those in strokes

What do lasers, neural networks, and spreading epidemics have in common? They share a most basic feature whereby an initial pulse can propagate through a medium—be it physical, biological or socio-economic, respectively. The challenge is to gain a better understanding—and eventually control—of such systems, allowing them to be applied, for instance to real neural systems. This is the objective of a new theoretical study published in EPJ B by Clemens Bachmair and Eckehard Schöll from the Berlin University of Technology in Germany. Ultimately, with a better theoretical understanding, scientists aim to control such excitations in networks of neurons to prevent their detrimental effects like in stroke.

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EPJ B Video - Competent Editorial Staff and Quick Handling System

Here's why you should publish your article on condensed matter or complex systems in EPJ B.

EPJ B Colloquium - Femto-nano-optics: ultrafast nonlinearity of metal nanoparticles

Pump-probe optical spectroscopy setup for single nanoparticle experiments

A deep understanding of the internal dynamics of metal nanoparticles, through the measurement of their time resolved optical response, requires detailed modeling of the physical processes involved. This EPJ B Colloquium explores the nonlinear ultrafast optical response of metal nanoparticles which can be obtained experimentally in ensembles and single nanoparticles, through femtosecond pump-probe spectroscopy.

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EPJ B Highlight - On-demand conductivity for graphene nanoribbons

Sketch of a kicked zigzag graphene nanoribbon. © D. Babajanov et al.

Physicists from Uzbekistan and Germany have devised a theoretical model to tune the conductivity of graphene zigzag nanoribbons using ultra-short pulses

Physicists have, for the first time, explored in detail the time evolution of the conductivity, as well as other quantum-level electron transport characteristics, of a graphene device subjected to periodic ultra-short pulses. To date, the majority of graphene studies have considered the dependency of transport properties on the characteristics of the external pulses, such as field strength, period or frequency. The new findings have now been published in EPJ B by Doniyor Babajanov from the Turin Polytechnic University in Tashkent, Uzbekistan, and colleagues. These results may help to develop graphene-based electronic devices that only become conductors when an external ultra-short pulse is applied, and are otherwise insulators.

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EPJ B Video - EPJ B Colloquia, introductions to new research directions

Luciano Colombo explains the benefits of colloquia papers in EPJ B.

EPJB Colloquium - Embedded nanocrystals get reshaped by ion beams

A new Colloquium paper published in EPJ B looks at ion irradiation techniques as a means to control the structure of nanoclusters and nanocrystals embedded in solid materials, such as silica or silicon.

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EPJ B Highlight - Taking advantage of graphene defects

The scattering potential in real space calculated based on the Fourier image. © S. Koniakhin

New theoretical model of the effect of triangular defects in graphene provides numerical estimates of the resulting current rectification with potential applications in security screening.

Electronic transport in graphene contributes to its characteristics. Now, a Russian scientist is proposing a new theoretical approach to describe graphene with defects—in the form of artificial triangular holes—resulting in the rectification of the electric current within the material. Specifically, the study provides an analytical and numerical theory of the so-called ratchet effect —which results in a direct current under the action of an oscillating electric field, due to the skew scattering of electronic carriers by coherently oriented defects in the material. These findings are published in EPJ B by Sergei Koniakhin from the Ioffe Physical-Technical Institute and the Academic University - Nanotechnology Research and Education Centre, both affiliated with the Russian Academy of Sciences in St. Petersburg.

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EPJ B Highlight - Nano-pea pod model widens applications

The dependence of the continuous spectrum on the connecting wires’ length. © Eremin et al.

A new theoretical model outlines the conditions under which a novel nanostructure, such as the nano-pea pod, can exhibit localised electrons for electronics applications

Periodic chain-like nanostructures are widely used in nanoelectronics. Typically, chain elements include the likes of quantum rings, quantum dots, or quantum graphs. Such a structure enables electrons to move along the chain, in theory, indefinitely. The trouble is that some applications require localised electrons - these are no longer in a continuous energy spectrum but in a discrete energy spectrum, instead. Now, a new study by Russian scientists identifies ways of disturbing the periodicity of a model nanostructure to obtain the desired discrete spectrum with localised electrons. These findings have been published in EPJ B by Dr. Eremin from the Mordovian State University, in Saransk, Russia and colleagues.

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EPJ B Highlight - Inter-dependent networks stress test

Impact of network topologies. © Fu et al.

A new study relies on a complex systems modelling approach, known as graph theory, to analyze inter-dependent physical or social networks and improve their reliability in the event of failure

Energy production systems are good examples of complex systems. Their infrastructure equipment requires ancillary sub-systems structured like a network - including water for cooling, transport to supply fuel, and ICT systems for control and management. Every step in the network chain is interconnected with a wider network and they are all mutually dependent. A team of UK-based scientists has studied various aspects of inter-network dependencies, not previously explored. The findings have been published in EPJ B by Gaihua Fu from Newcastle University, UK, and colleagues. These findings could have implications for maximising the reliability of such networks when facing natural and man-made hazards.

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Executive Editors:
Eduardo Hernandez, Heiko Rieger, Bikas K. Chakrabarti, Wenhui Duan
Thank you for the very fruitful and efficient collaboration. It has been a pleasure!!

Paul van Loosdrecht, Guest Editor Topical issue: Excitonic Processes in Condensed Matter, Nanostructured and Molecular Materials, 2013

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

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

Conference announcements

POSMOL 2017

Magnetic Island, Queensland, Australia, 22-24 July 2017