EPJ Special Topics (EPJ ST)

2021 Impact factor 2.891

Special Topics

EPJB Highlight - Picosecond-range control over information processing

Details: Published on 12 January 2015

Energy levels of the parabolic QD versus the strength of the Rashba SOC. © J. A. Budagosky *et al.*

Optical manipulation is key to reaching the necessary speed to control the furtive underlying physical mechanism used in quantum information processing

Quantum computing will, one day, bring quicker information processing. One of the keys to such speed is being able to control the short-lived physical phenomenon holding quantum information, also known as quantum bits (qubits). A new study presents a novel optical manipulation technique to control one possible kind of qubit—represented, in this case, by polarised electron spins—exposed to an ultra-short pulsed laser in the picosecond-range. Jorge Budagosky and Alberto Castro from the University of Zaragoza, Spain, have tested this novel optics approach using a quantum dot—nanoscopic artificial structures with a small number of electrons—in a study published in EPJ B.

EPJ B Highlight - Winner and losers of the EU funding challenge

Details: Published on 10 December 2014

A representative Minimum Spanning Tree of the network of countries involved in the FP7 accepted proposals, which captures the backbone of interactions between the countries. © M.Tsouchnika *et al.*

Successfully attracting EU funding could depend on the nature of the research consortium

The European Union has a well-oiled funding mechanism in the form of grants given to research consortia. These are essentially made up of collaborating academic and industry-based research organisations. Understanding which type of consortium work receives funding could help future applicants. And it could also bring further transparency on how public funds are spent. Now, Maria Tsouchnika and Panos Argyrakis from the University of Thessaloniki, Greece, have brought valuable insights into the structure of research consortia that are most likely to attract EU funding, in a paper published in EPJ B.

EPJ B Highlight - When noise gets electrons moving

Details: Published on 02 December 2014

Realisations of harmonic noise. © D. V. Makarov *et al.*

A new study demonstrates the existence of a counter-intuitive current, induced by the sound-based equivalent of a laser, with applications in novel microscopic semiconductor devices

Studying the motion of electrons in a disordered environment is no simple task, mainly because given the effect occurring at the scale of interest—referred to as quantum scale—these electrons are otherwise impossible to examine, due to the presence of incidental phenomena. Often, understanding such effects requires a quantum simulator designed to expose them in a different physical setup. This is precisely the approach adopted by Denis Makarov and Leonid Kon’kov from the Victor I. Il’ichev Pacific Oceanological Institute in Vladivostok in a new study published in EPJ B. They relied on a simulator of electronic motion subjected to noise stemming from a flux of sound waves. These findings could lead to semi-conductor devices of a new kind, operated through acoustic radiations.

EPJ B Colloquium - Tensor network theory

Details: Published on 01 December 2014

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.

EPJ B Highlight - Taming neural excitations

Details: Published on 25 November 2014

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.

EPJ B Video - Competent Editorial Staff and Quick Handling System

Details: Published on 10 November 2014

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

Details: Published on 05 November 2014

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.

EPJ B Highlight - On-demand conductivity for graphene nanoribbons

Details: Published on 05 November 2014

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.

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

Details: Published on 22 October 2014

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

EPJB Colloquium - Embedded nanocrystals get reshaped by ion beams

Details: Published on 20 October 2014

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.