2022 Impact factor 1.8
Atomic, Molecular, Optical and Plasma Physics

EPJ B Highlight - Investigating the use of noise to solve inverse physical problems

A graphical representation of a seismic inversion problem. Credit: Corso, et al, (2023)

New research looks at the problem of solving a physics problem starting with observational data and working backwards

The early success of physics comes mainly from solving direct or forward problems in which the physical state of a system can be described from a well-defined physical model and from governing equations. Yet, there exists a different type of problem, inverse problems, that are trickier to solve but are crucial to fields such as engineering, astrophysics and geophysics.

Solving these inverse problems requires taking a set of observational data and then working backwards, or inverting the problem, to arrive at the causal factors that gave rise to the data.

A new paper in EPJ B by Universidade Federal do Rio researchers Gilberto Corso and João Medeiros de Araujo, considers the possibility of solving inverse problems in physics by using statistical information from noise statistics.

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EPJ B Highlight - Uncovering spin ladders in real compounds

Ladder in a low-dimensional spin system

Low-dimensional quantum systems named ‘spin ladders’ are strongly linked to superconductivity. A new theoretical approach has accurately predicted the nature of the spin ladder which appears in real chemical compound – possibly paving the way for new discoveries of advanced superconductors.

When fabricated in 1 or 2 dimensions, systems of particles whose quantum spins interact with each other can display some unique quantum properties. Through new research published in EPJ B, Asif Iqbal and Baidur Rahaman at Aliah University in Kolkata, India, developed a new theoretical technique for calculating the structures and interactions taking place in these unique materials. Their approach could pave the way for advanced new superconductors – which allow electric currents to flow through them with zero resistance.

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EPJ B Highlight - Statistical physics reveals how languages evolve

Charting the survival of linguistic structures

Models based on the principles of statistical physics can provide useful insights into how languages change through contact between speakers of different languages. In particular, the analysis reveals how unusual linguistic forms are more likely to be replaced by more regular ones over time.

The field of historical linguistics explores how languages change over time, with a particular focus on the evolution of sounds, meanings, and structures in words and sentences. So far, however, it hasn’t been widely studied from the viewpoint of statistical physics – which uses mathematical models to explain patterns and behaviours in complex, evolving systems. Through a series of models described in EPJ B, Jean-Marc Luck at Université Paris-Saclay, together with Anita Mehta at the Clarendon Institute in Oxford, use statistical physics to show how exceptions to well-established grammatical rules are linked to the influence of neighbouring languages.

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EPJ B Highlight - 2D Janus materials could harvest abundant hydrogen fuel

Top and side views of the Janus monolayer

A new group of asymmetric 2D materials can readily catalyse the splitting of water into hydrogen and oxygen – providing a reliable source of hydrogen fuel.

Several studies have predicted that the water splitting reaction could be catalysed by certain groups of 2D materials – each measuring just a few atoms thick. One particularly promising group are named 2D Janus materials, whose two sides each feature a different molecular composition. Through new calculations detailed in EPJ B, Junfeng Ren and colleagues at Shandong Normal University in China present a new group of four 2D Janus materials, which could be especially well suited to the task.

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EPJ B Highlight - Examining heat transfer in granular materials

Heat transfer via gas and water capillaries

Heat transfer through granular materials in a humid atmosphere occurs mainly through the air in the case of larger particles, and via water capillary bridges for smaller particles.

Granular materials contain large numbers of small, discrete particles, which collectively behave like uniform media. Their thermal conductivity is crucial to understanding their overall behaviour – but so far, researchers haven’t considered how this value is affected by the surface roughness of their constituent particles. Through new analysis published in EPJ B, Bo Persson at the Peter Grünberg Institute, part of the Jülich Research Centre in Germany, has discovered that when this roughness is considered, thermal conductivity in granular materials is heavily influenced by particle sizes. These findings could help physicists to better describe a wide array of granular materials: from sand and snow, to piles of rice, coffee beans, and fertilizer.

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EPJ B Highlight - Finely-tuned quantum dots enhance nonlinear optics

Quantum dot with a spherical impurity

Quantum dots with finely-tuned spherical defects could display advanced ‘nonlinear’ optical properties, new calculations have suggested. Adjusting the sizes of these defects could enable researchers to tightly control the brightness and frequency of the light they produce when illuminated.

Quantum dots are semiconductor particles measuring just a few nanometres across, which are now widely studied for their intriguing electrical and optical properties. Through new research published in EPJ B, Kobra Hasanirokh at Azarbaijan Shahid Madani University in Iran, together with Luay Hashem Abbud at Al-Mustaqbal University College, Iraq, show how quantum dots containing spherical defects can significantly enhance their nonlinear optical properties. By fine-tuning these defects, researchers could tightly control the frequency and brightness of the light emitted by quantum dots.

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In Memory of Prof Amit Dutta

It is with great sadness that we learn of the sudden passing of Professor Amit Dutta (Indian Institute of Technology, Kanpur, India), member of the Editorial Board of EPJB. An elected Fellow of the Indian Academy of Sciences, Bengaluru, Prof Dutta was a member of the Physics Department at IIT Kanpur since 2003, having obtained his PhD from Jadavpur University in 2000. He was a post-doctoral fellow at the Max-Plank-Institut fur Physik Komplexer Systeme, Dresden and the Institut fur Theoretishe Physik, Universitat Wurzburg, and his research interests were in the fields of quantum phase transitions, non-equilibrium dynamics of quantum many body systems and quantum information.

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EPJ B Topical Issue on Recent developments in the functional renormalization group approach to correlated electron systems

Guest editors: Carsten Honerkamp, Dante Kennes, Volker Meden, Michael Scherer and Ronny Thomale.

This Topical Issue of EPJ B brings together a collection of articles on the recent progress of the application of the functional renormalization group to correlated electron systems.

In condensed-matter physics strong correlations between electrons in materials and devices are responsible for the formation of many intriguing emergent phenomena, including various types of magnetism, (unconventional) superconductivity, Kondo-like effects or interaction-induced topological phases. Theoretical progress in the understanding of correlated electron systems requires the dedicated development of modern and powerful quantum many-body methods. One rather versatile method is the functional renormalization group, which has recently witnessed major methodological advances and extensions. This includes aspects of the renormalization group formulation, increased computer power and enhanced interlinks to ab initio quantum material methods, extensions to novel strongly correlated electronic models, and electronic systems out of equilibrium.

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EPJ B Highlight - Assessing the effect of hydraulic fracturing on microearthquakes

A cross-section of a hydrofracturing site showing preconditioning by blasting. Credit: de la Barra. E., et al, [2022]

New research examines mining sites with hydraulic fracturing comparing it to those without to determine the practice’s effect on seismic hazards.

The analysis of low-intensity human-caused microearthquakes, including their magnitude and frequency, has become an important factor in mining. This is a consideration not only for the safety of mining staff, but also for extraction rates and mine stability that can have major impacts on business performance. Increasingly, the practice of hydraulic fracturing is used to precondition mines and diminish the magnitude of induced tremors as well as reduce the number of rock fragments extracted.

A new paper published in EPJ B assesses the impact of hydraulic fracturing on seismic hazards like microearthquakes, an important issue for the safety of workers and the continuation of mining operations. The paper is authored by Erick de la Barra, Pedro Vega-Jorquera and Héctor Torres from the University of La Serena, Chile, alongside Sérgio Luiz E. F. da Silva from Politecnico di Torino, Department of Applied Science and Technology, Turin, Italy.

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EPJ B Highlight - Bringing consistency to methods of 2D material analysis

A sheet of 2D material-graphene-curved to create a nanotube. Credit: Michael Ströck (CC by SA 3.0)

New research introduces a more cohesive approach to the functional renormalization group — a key tool in the analysis of 2D materials

In materials science, the term “2D materials” refers to crystalline solids that consist of a single layer of atoms, with arguably the most famous example being graphene — a material made of a single layer of carbon atoms. These materials are promising for a wide range of applications including in sophisticated electronics and quantum computing thanks to their unique quantum properties.

One of the most promising methods of investigating these materials, and specifically their temperature instabilities, and for investigating quantum many-body phenomena is the functional renormalisation group (FRG). Yet, despite significant efforts, no systematic and comprehensive cohesion exists for different momentum space FRG implementations.

A new paper published in EPJ B and authored by Jacob Beyer, Institute for Theoretical Solid State Physics, RWTH Aachen University, Germany, alongside Jonas B. Hauck, and Lennart Klebl of the university’s Institute for Theory of Statistical Physics lays out a potential groundwork for achieving consistency across FRG methods.

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Editors-in-Chief
A. Beige, J. Burgdörfer and S. Ptasinska
It was a pleasure to collaborate with your journal as a referee. Also in the future I will be pleased to do this again.

Tomaz Gyergyek

ISSN (Print Edition): 1434-6060
ISSN (Electronic Edition): 1434-6079

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