News

EPJ D Highlight - Atoms crystallised by light for precision measurement

Details: Published on 26 November 2014

Trajectories and intensities of two beam splitters. © D. Holzmann *et al.*

A new study focuses on the collective dynamics of illuminated atoms coupled to photons travelling in a nanofiber

Theoretical physicists have uncovered the existence of self-organised dynamics of atoms, bound by light into a crystal, with long range atom-atom interactions. These findings were recently published in EPJ D by Daniela Holzmann from the University of Innsbruck, Austria, and colleagues. This approach could, among others, help to better understand the process of crystallisation in new materials, and help implement efficient photon storage and precision measurements. Applied to ultra-cold atoms, it could aid in the study of long-distance interactions in the quantum dynamics of one-dimensional non- conventional materials, referred to as exotic matter.

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 D Colloquium - Multiscale approach to the physics of radiation damage with ions

Details: Published on 24 November 2014

Features, processes, and disciplines, associated with radiation therapy shown in a space–time diagram, which shows approximate temporal and spatial scales of the phenomena. The history from ionization/exciation to biological effects on the cellular level are shown in the main figure and features of ion propagation are shown in the inset.

In this EPJ D Colloquium, the authors review the multiscale approach to the assessment of biodamage that results from the irradiation of biological media with ions. This approach is explained in depth and compared to other approaches. The ion propagation processes that take place in the medium concurrent with ionisation and excitation of molecules, transport of secondary products, dynamics of the medium, and biological damage, take place on a number of different temporal, spatial and energy scales. The multiscale approach, a physical phenomenon-based analysis of the scenario that leads to radiation damage, has been designed to consider all relevant effects on a variety of scales and to enable quantitative assessment of biological damage as a result of irradiation with ions.

EPJ D Colloquium - Laser selective spectromicroscopy of myriad single molecules: tool for far-field multicolour materials nanodiagnostics

Details: Published on 14 November 2014

An illustration of the principles of single-molecule spectromicroscopy

In this EPJ D Colloquium, the authors discuss the main principles, achievements and perspectives in the fields of highly-parallel luminescence spectroscopy and the imaging of single molecules (SMs) in transparent solids. Special attention is given to SM detection at low temperatures, where ultranarrow and bright zero-phonon lines (ZPLs) can be generated by emitting centres for observation.

EPJ H Highlight - Penrose’s and Hawking’s early math award

Details: Published on 11 November 2014

Find out how Roger Penrose and Stephen Hawking won recognition for their work on space time singularities back in the sixties, suggesting an initial start to the universe

In 1966, it was Roger Penrose who won the prestigious Adams prize for his essay: An Analysis of the Structure of Space Time. The Adams prize—named after the British mathematician John Couch Adams—is awarded each year by the Faculty of Mathematics at the University of Cambridge to a young, UK-based mathematician. At the same time, Stephen Hawking won an auxiliary to the Adams prize for an essay entitled Singularities and the Geometry of Spacetime, shortly after completing his PhD. A copy of the original submission has now been reproduced in EPJ H.

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 D Highlight - Plasma: Casimir and Yukawa mesons

Details: Published on 29 October 2014

Energy correction factor for two gold plates in the absence of any intervening plasma. © Ninham *et al.*

The Casimir electromagnetic fluctuation forces across plasmas are analogous to so-called weak nuclear interaction forces, as new findings show

A new theoretical work establishes a long-sought-after connection between nuclear particles and electromagnetic theories. Its findings suggests that there is an equivalence between generalised Casimir forces and what are referred to as weak nuclear interactions between protons and neutrons. The Casimir forces are due to the quantisation of electromagnetic fluctuations in vacuum, while the weak nuclear interactions are mediated by subatomic scale particles, originally called mesons by Yukawa. These findings by Barry Ninham from the Australian National University, in Canberra, and European colleagues, have now been published in EPJ D.

EPJ A Highlight - Achieving high resolution in binary nuclear reactions with outgoing fast neutrons – at last!

Details: Published on 28 October 2014

To date, the two-nucleon pick-up and stripping counterparts of the (p,t) and (t,p) reactions, the (³He,n) and (n, ³He) reactions, have been poorly investigated due to the difficulty in performing high-resolution measurements of fast-neutron energies. The best time-of-flight (³He,n) measurements report resolutions not better than 250 keV. This lack of experimental resolution has hindered a full understanding of the role of proton pairing in nuclei.