2012 Impact factor 1.282
EPJ B - Condensed Matter and Complex Systems
Condensed Matter and Complex Systems
News / Highlights / Colloquium
EPJ B Highlight - Nanoscale heat flow predictions
Tuesday, 22 April 2014 12:02
Snapshot of the final configuration of a nc-Si sample. © Melis et al.

A new study predicts that heat flow in novel nanomaterials could contribute to creating environmentally friendly and cost-effective nanometric-scale energy devices

Physicists are now designing novel materials with physical properties tailored to meet specific energy consumption needs. Before these so-called materials-by-design can be applied, it is essential to understand their characteristics, such as heat flow. Now, a team of Italian physicists has developed a predictive theoretical model for heat flux in these materials, using atom-scale calculations. These findings, published in EPJ B by Claudio Melis and colleagues from the University of Cagliary, Italy, could have implications for optimising the thermal budget of nanoelectronic devices—which means they could help dissipate the total amount of thermal energy generated by electron currents—or in the production of energy through thermoelectric effects in novel nanomaterials.

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EPJ B Highlight - Grasp of SQUIDs dynamics facilitates eavesdropping
Tuesday, 08 April 2014 09:29
Average voltage output of a DC SQUID under varying conditions. © Berggren et al.

Latest theoretical advances pertaining to the dynamics of highly sensitive magnetometers could find military applications in low-noise amplifiers and sensitive antennas

Theoretical physicists are currently exploring the dynamics of a very unusual kind of device called a SQUID. This Superconducting Quantum Interference Device is a highly sensitive magnetometer used to measure extremely subtle magnetic fields. It is made of two thin regions of insulating material that separate two superconductors – referred to as Josephson junctions – placed in parallel into a ring of superconducting material. In a study published in EPJ B, US scientists have focused on finding an analytical approximation to the theoretical equations that govern the dynamics of an array of SQUIDs. This work was performed by Susan Berggren from the US Navy research lab, SPAWAR Systems Center Pacific, in San Diego, CA, USA and Antonio Palacios San Diego State University. Its applications are mainly in the military sector, including SQUID array-based low-noise amplifiers and antennas.

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EPJ B Highlight - Graphene nanoribbons as electronic switches
Monday, 31 March 2014 12:32
© Credit: Dmitry Knorre/Fotolia

A new theoretical study shows the conductivity conditions under which graphene nanoribbons can become switches in externally controlled electronic devices

One of graphene’s most sought after properties is its high conductivity. Argentinian and Brazilian physicists have now successfully calculated the conditions of the transport, or conductance mechanisms, in graphene nanoribbons. The results, recently published in a paper in EPJ B, yield a clearer theoretical understanding of conductivity in graphene samples of finite size, which have applications in externally controlled electronic devices.

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EPJB Colloquium – From SiC to fluorescent SiC based white LEDs
Tuesday, 11 March 2014 13:44
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Three free standing 3C-SiC substrates with size 10x10 mm (Fig. 16).

A new EPJ B Colloquium reviews the latest advances in silicon carbide (SiC) for optoelectronics. The wide bandgap of SiC makes it a great semiconductor material to make devices for in high power, high frequency and high temperature applications.

During the past decade, SiC has also become a promising materials for light-emitting diodes (LED), since it was found that co-doping it with nitrogen and boron produces a high donor-acceptor pair emission efficiency. Fluorescent SiC based white LED light source is an innovative concept for optoelectronic devices.

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EPJB Review - New promising bulk thermoelectrics
Tuesday, 11 March 2014 10:05
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Superlattice structure of (BiS)1.2(TiS2)2 misfit layer sulfide. (Fig. 15).

The growing need for alternative “green” energy sources has prompted renewed interest in thermoelectric materials. These materials can directly convert heat to electricity or, conversely, use electrical current to cool. The thermoelectric performance of a material can be estimated by the so-called figure of merit, zT = σα2T/λ (α is the Seebeck coefficient, σα2 is the power factor, σ and λ are the electrical and thermal conductivity, respectively), the value of which depends only on the material.

In a new EPJ B review, authors Gonçalves and Godart discuss the state of the art in this field, with special emphasis on the strategies to reduce the lattice part of the thermal conductivity and maximize the power factor in thermoelectric materials.

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EPJ B Highlight - Football displays fractal dynamics
Wednesday, 05 March 2014 13:00
Players’ and ball’s positions captured on video. © Kijima et al.

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.

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EPJ B Highlight - Probing the edge of chaos
Tuesday, 18 February 2014 15:19
Fractals. © wajakaa - Photolia

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.

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EPJ B Highlight - Optimising custody is child’s play for physicists
Tuesday, 11 February 2014 09:02
A graph depicting the children’s custody problem, where grey nodes represent couples. © Gomberoff et al.

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.

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EPJ B Highlight - Bottom-up insight into crowd dynamics
Tuesday, 04 February 2014 16:47
In the simulations, agents are grouped into six zones based on their initial distances from the exit. © Viswanthan et al.

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.

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EPJ B Colloquium - Thermodynamics and kinetics properties of condensed matter derived through the properties of an intrinsic defect
Friday, 24 January 2014 06:42
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Elementary jump of an interstitialcy in an fcc Lattice. Open circles (red), before jump; closed circles (blue), after jump (Fig. 6 from the paper).

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.

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Editors-in-Chief
P. Hänggi and A. Rubio
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