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EPJ D Highlight - Novel beams made of twisted atoms

‘Snapshot’ of atomic Bessel beam profiles.

Scientists can now theoretically construct atomic beams of a particular kind, opening the door for applications in fields like quantum communication.

Physicists have, for the first time, now built a theoretical construct of beams made of twisted atoms. These findings are about to be published in EPJ D by Armen Hayrapetyan and colleagues at Ruprecht-Karls-University Heidelberg in Germany. These so-called atomic Bessel beams can, in principle, have potential applications in quantum communication as well as in atomic and nuclear processes.

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EPJ A Highlight - Dissecting Deuteron Compton Scattering I: The Observables with Polarised Initial States

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Sensitivity of a double-polarisation-asymmetry observable to the E1-M2 spin polarisability.

The electromagnetic polarisabilities of the nucleons characterise their responses to external fields. The simplest are the electric and magnetic polarisabilities that describe the induced dipole moments. For spin-1/2 particles there are also four spin polarisabilities, analogous to rotations of the polarisation of light by optically active media. The best experimental window on them is Compton scattering of photons, which has provided good determinations of the electric and magnetic polarisabilities of the proton. Future experiments with polarised protons will give access to its spin polarisabilities. In contrast, much less is known of about the neutron since it does not exist as a stable target. Nonetheless, its properties can be obtained from Compton scattering on light nuclei, most notably the deuteron -- a weakly bound proton and neutron. A new generation of experiments is planned to provide beams of polarised photons on targets of polarised deuterons. If the spins of the final particles are not observed, there are 18 independent observables. This work provides, for the first time, the complete set of these, which will be needed for the experimental analyses. More importantly, it also examines their sensitivities to the various polarisabilities, which will be crucial for the design of the experiments.

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EPJ B Highlight - Studying emotions causing opinions to change

Example of evolution of agent opinions.

Physicists can use their tools to help understand how, in real life, opinions form and change by modelling the complex interactions between information and emotion

Social phenomena fascinate with their complexity, but are not easily understood. Pawel Sobkowicz, an independent researcher based in Warsaw, Poland, has developed a model to study the dynamic of standard people, called ‘agents’, and their response to a given piece of information, depending on their emotional state. In a study just published in EPJ B, the author shows that opinion dynamics differ depending on whether the agent is agitated or not.

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EPJ E Highlight - Protein surfaces defects as drug targets

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The average mobility of the water molecules. Figure 2 from Ariel Fernandez (2010), Transformative concepts for drug design: Target Wrapping, Springer-Verlag, Berlin.

Drug designers now have a new way of designing drug candidates suitable for dislodging unstable water molecules located in the defects at the surface of target proteins

New research shows a physical characterisation of the interface of the body’s proteins with water. Identifying the locations where is it easiest to remove water from the interface of target proteins could constitute a novel drug design strategy. The candidate drugs would need to be engineered to bind at the site of the protein where interfacial water is most easily dislodged. These findings, based on the work of María Belén Sierra from the National University of the South, in Bahia Blanca, Argentina and colleagues, recently published in EPJ E.

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EPJ E Highlight - Heterogeneous nanoblocks give polymers an edge

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Examples of different nanoscale patterns that block copolymers can adopt.

Study uncovers the effects of size variation in nanoscale blocks used in polymer mixes on their underlying architecture and inherent characteristics

Building structures by mixing lego bricks of two different sizes is child’s play. However, studying polymers endowed with an alternating nanostructure made of heterogeneous blocks is anything but straightforward. Theoretical physicist Mark Matsen, based at the University of Reading, UK, studies polymer mixes consisting of two-fold (AB) and three-fold (BAB) combinations of two types of nanoscale blocks. He has shown, in a study published in EPJ E, that the underlying heterogeneity of the blocks can cause polymers to switch to different nanoscale patterns and therefore display different properties. Numerous applications based on etching patterns on substrates, such as electronics, computer chips, and membranes endowed with a specific function, can benefit from such research.

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EPJ E Highlight - Cells move as concentration shifts

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Schematic representation of a top-view of the cell containing the colony.

Sheets of biological cells move along the organs they cover by altering the external concentrations of specific molecules, thanks to an absorption mechanism on the cells’ surface

What do wound healing, cancer metastasis, and bacteria colonies have in common? They all involve the collective displacement of biological cells. New research sheds some new light on the physical mechanisms provoking the displacement of a sheet of cell, known as an epithelium. It typically covers our organs including the stomach and intestine, as well as our epidermis. In a paper which appeared in EPJ E, Martine Ben Amar from Pierre and Marie Curie University in Paris explains the importance of understanding the displacement of the epithelium as a means of influencing the biological process involved in healing. And, ultimately, of helping to minimise scars.

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EPJ C Highlight - Removing complexity layers from the universe’s creation

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A schematic depiction of the combined motion that a Brownian particle executes in a background polycrystalline space. © The authors

Understanding complexity in the early universe may require combining simpler models to interpret cosmological observations

Complicated statistical behaviour observed in complex systems such as early universe can often be understood if it is broken down into simpler ones. Two physicists, Petr Jizba (currently affiliated with the Czech Technical University in Prague), and Fabio Scardigli (now working at Kyoto University in Japan), have just published results in EPJ C pertaining to theoretical predictions of such cosmological systems’ dynamics.

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EPJ D Highlight - The key to ion beams’ polarisability

Ion beams are used as a source for dopant atoms in semiconductor manufacturing. © Hornpipe, Dreamstime Stock Photos & Stock Free Images

Polarisability for series of multi-electron ions is now available

Polarisability determines the force with which an inhomogeneous external electric field acts on the ions of an ion beam. However, it can be quite tricky to obtain accurate values for this force. Now, two German theoretical chemists, Volker Koch from Bielefeld University and Dirk Andrae from the Free University Berlin, have devised formulas providing the polarisability of atomic ions as a function of their total charge number. Their findings, about to be published in EPJ D, have implications for many applications, ranging from the use of ion beams for research purposes or as a source for dopant atoms in semiconductor manufacturing to the modelling of planetary and stellar atmospheres.

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EPJ B Highlight - When diffusion depends on chronology

Motorways are an example of nodes connected by edges studied as complex networks.
© Highways Agency

Study shows that the order of events taking place in complex networks may dramatically alter the way diffusion occurs

The Internet, motorways and other transport systems, and many social and biological systems are composed of nodes connected by edges. They can therefore be represented as networks. Scientists studying diffusion over such networks over time have now identified the temporal characteristics that affect their diffusion pathways. In a paper just published in EPJ B, Renaud Lambiotte and Lionel Tabourier from the University of Namur, Belgium, together with Jean-Charles Delvenne from the Catholic University of Louvain, Belgium, show that one key factor that can dramatically change a diffusion process is the order in which events take place in complex networks.

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EPJ B Highlight - Semantics on the basis of words’ connectivity

Illustration of a tourist walk.

It is now possible to identify the meaning of words with multiple meanings, without using their semantic context

Two Brazilian physicists have now devised a method to automatically elucidate the meaning of words with several senses, based solely on their patterns of connectivity with nearby words in a given sentence – and not on semantics. Thiago Silva and Diego Amancio from the University of São Paulo, Brazil, reveal, in a paper just published in EPJ B, how they modelled classics texts as complex networks in order to derive their meaning. This type of model plays a key role in several natural processing language tasks such as machine translation, information retrieval, content analysis and text processing.

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Editors-in-Chief
L. Baudis, G. Dissertori, K. Skenderis and D. Zeppenfeld

Deputy Editors-in-Chief
D. J. Schwarz

Thank you for accepting the paper. Thanks also to the Associate Editor and the referee for their speedy and helpful comments during the review process. I will definitely keep EPJC in mind for future contributions.

Ravi Kuchimanchi

ISSN: 1434-6052 (Electronic Edition)

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