2023 Impact factor 0.8
Historical Perspectives on Contemporary Physics


EPJ B Highlight - Coalescence-fragmentation cycles based on Human conflict

Lewis Richardson’s models of insurgency warfare applies to general group dynamics. Credit: NOAA Presentation/Public Domain

Inspired by insurgency warfare dynamics, a model predicts patterns of how groups gel and shatter

In 1960, Lewis Fry Richardson famously observed that the severity of a wartime event is described by a simple power law distribution that scales according to the size of the conflict. Statisticians since have since proposed various modifications, but they continue to agree that casualty count in a violent conflict tends to scale with the size of the insurgent group that caused the conflict. In a study published in EPJ B, Brennen Fagan, of the University of York, UK, and his colleagues analyze models of how complex systems coalesce and fragment based on these warfare dynamics. Their work evaluates the robustness of these models and elucidates the relationship between microscopic dynamics and observed phenomena.


EPJ B Highlight - Exploring exotic behaviours in population-imbalanced fermionic systems

Forming exotic phases of matter

New studies show that oscillations in the quantum states of composite particles in trapped systems can be adjusted using an external magnetic field.

Over the past 20 years, many physicists have studied ultra-cold fermionic systems contained in magnetic or optical traps. When an external magnetic field is applied to a two-species fermionic system, the particles can pair together to form composite ‘bosonic molecules’ with a full-integer spin. These molecules undergo “Bose-Einstein Condensation” when cooled, where all the particles accumulate in the lowest-energy quantum state. The precision of these experiments has now been improved by trapping the particles inside optical lattices: periodic patterns formed by counter-propagating laser beams.

Through new research published in EPJ B, Avinaba Mukherjee and Raka Dasgupta at the University of Calcutta, India, have theoretically predicted a distinctive trend in the oscillations of Bose-Einstein condensates formed from these fermions – which can be adjusted using an external magnetic field. They specifically addressed systems where the two species have unequal population (creating leftover unpaired fermions): leading to exotic new phases. Their result could help physicists to detect such novel phases of matter in imbalanced fermionic systems and could open up new opportunities for quantum technologies.


EPJ B Highlight - Harvesting vibrational energy from coloured noise

Schematic diagram of a tri-stable energy harvesting system with linked electronics and energy store. Credit: T. Zhang, Y. Jin

Two engineers from Beijing Institute of Technology in China have shown how to optimise the output of a device that can convert ambient vibrational energy into useful electric power.

The energy demands of today’s ubiquitous small electronic devices – including sensors, data transmitters, medical implants and ‘wearable’ consumer products such as Fitbits – can no longer be met by chemical batteries alone. This gap can be filled by energy harvesters, which turn ordinary, ambient vibrational energy into electrical energy. The most efficient types of harvester are tri-stable energy harvesters, which can convert even low-frequency random vibrations into alternating current (AC) and thence into direct current (DC). Tingting Zhang and Yanfei Jin from Beijing Institute of Technology in China have now investigated how the properties of these systems can be altered to optimise the power output; their findings are published in EPJ B.


EPJ Plus Highlight - Beam balance designs could elucidate the origins of dark energy

The beam balance prototype

With some improvements, the instrument could help physicists to identify the mysterious origins of dark energy.

One of the greatest problems in modern physics is to reconcile the enormous difference between the energy carried by random fluctuations in the vacuum of space, and the dark energy driving the universe’s expansion.

Through new research published in EPJ Plus, researchers led by Enrico Calloni at the University of Naples Federico II, Italy, have unveiled a prototype for an ultra-precise beam balance instrument, which they hope could be used to measure the interaction between these vacuum fluctuations and gravitational fields. With some further improvements, the instrument could eventually enable researchers to shed new light on the enigmatic origins of dark energy.


EPJ QT Highlight - Access to burgeoning quantum technology field could be widened by open master educational model

The operation of the Open Master pilot scheme. Credit: S. Goorney, et al., EPJ Quantum Technology, (2024)

Quantum technology offers major societal benefits, but its growth depends on the supply of a qualified workforce.

Quantum Technology is based on the engineering of devices that make use of the quantum properties of matter. One of the most prominent avenues of this technology is quantum computing, which may be able to leverage quantum bits (qubits) to perform calculations more efficiently than classical computers. Technology with this “quantum advantage” will also operate in the background of our lives, providing ultra-secure communications and high-precision sensors and clocks.

The applications of quantum technology have led to a boom in investment worldwide; with this technology expected to have a huge societal impact. But to maintain this burgeoning industry, it is crucial that graduates with training in quantum technology enter the workforce. Plus, for the European Union to stay ahead in the quantum tech race, the workforce must assemble on a much shorter timescale than the 3 to 5 years (or more) of a PhD program.

In a new paper in EPJ Quantum Technology, author Simon Goorney, from Aarhus University, Denmark, and his co-authors describe the development of Open Master, a new form of transnational education, that could serve as a means of enhancing accessibility to specialist expertise in quantum technology. The ultimate goal of the pilot scheme, which operated over the academic year of 2021 to 2022, was to use the experience to conceptualise a model for the future of quantum technology education.


EPJ E Highlight - Breaking an electrolyte’s charge neutrality

Electrical charge (red) builds up on a varied cross-section channel. Credit: Malgaretti et al. (2024).

Excess charge builds up in salt solutions due to interactions between electrostatic forces and a channel’s varying cross section

Plant vascular circulation, ion channels, our own lymphatic network, and many energy harvesting systems rely on the transport of dissolved salt solutions through tortuous conduits. These solutions, or electrolytes, maintain a positive or negative charge that’s vital to how the system functions. However, this charge balance depends on the properties of the channel that contains the fluid. In a study published in EPJ E, Paolo Malgaretti, of the Helmholtz Institute Erlangen-Nürnberg for Renewable Energy/Forschungszentrum Jülich, Germany, and his colleagues, now derive equations that describe how local electrical charge in electrolytes changes in channels with varying cross sections, at equilibrium. The result could help to predict pathways for charged particles in biological and technological systems.


EPJ Web of Conferences Highlight - MESON 2023 – 17th International Workshop on Meson Physics

MESON 2023 in Kraków, Poland.

The 17th International Workshop on Meson Physics-Meson 2023, took place in Kraków from 22nd to 27th June 2023.

The Meson conference series has a long standing tradition and is organised by the Institute of Physics of Jagiellonian University, GSI Helmholtz Centre for Heavy Ion Research, INFN-LNF Frascati and Institute of Nuclear Physics Polish Academy of Science, in Kraków. It brings together experimentalists and theorists involved in studies of meson production, interactions, internal structure and meson properties in strongly interacting matter.


EPJ Plus Highlight - Unlocking the full potential of Auger electron spectroscopy

Different regimes of core-hole creation and recombination

A new computational approach makes more realistic assumptions about the redistribution of energy during the Auger process, improving the accuracy of Auger electron spectroscopy.

Auger electron spectroscopy (AES) is an incredibly useful technique for probing material samples – but current assumptions about the process ignore some of the key time-dependent effects it involves. So far, this has resulted in overly-simplified calculations, which have ultimately prevented the technique from reaching its full potential.

Through a new study published in EPJ Plus, Alberto Noccera at the University of British Columbia, Canada, together with Adrian Feiguin at Northeastern University, United States, developed a new computational approach which offers a more precise theoretical description of the AES process, while taking its time dependence into account. Their method could help researchers to improve their quality of material analysis across a wide array of fields: including chemistry, environmental science, and microelectronics.


EPJ A Topical Collection: AGATA: Advancements in science and technology

Guest Editors: Nicolas Alamanos, Maria Jose Garcia Borge, Angela Bracco, Emmanuel Clément, Andres Gadea, Wolfram Korten, Silvia Leoni and John Simpson

The Advanced GAmma Tracking Array (AGATA) is a major European project, involving over 40 institutes in 12 countries, to develop and operate a high-resolution gamma-ray tracking spectrometer. Gamma-ray tracking requires the accurate determination of the energy, time and position of every interaction as a gamma ray deposits its energy within the detector volume. This is achieved by using electrically segmented hyper pure germanium detectors, pulse shape analysis of the digitised signals, and tracking algorithms to reconstruct the full event. The AGATA 4π geometry comprises 180 tapered-hexagonal coaxial detectors. AGATA can measure gamma rays from 10’s of keV to 10 MeV with excellent efficiency and position resolution and has a very high count rate capability. These features result in an instrument with a resolving power of two orders of magnitude larger than previous spectrometers, such as EUROBALL in Europe and Gammasphere in the USA. A similar tracking spectrometer is being constructed in the USA, called GRETA.


EPJ B Highlight - Investigating the role of random walks in particle diffusion

Distribution curve with sharp central peak

Theoretical analysis reveals new insights into unusual patterns displayed by diffusing particles in recent experiments.

Several recent experiments identify unusual patterns in particle diffusion, hinting at some underlying complexity in the process which physicists have yet to discover. Through new analysis published in EPJ B, Adrian Pacheco-Pozo and Igor Sokolov at Humboldt University of Berlin show how this behaviour emerges through strong correlations between the positions of diffusing particles travelling along similar trajectories. Their results could help researchers to create better models of the diffusion process – ultimately drawing deeper insights into how fluids behave.


A. Blum and M. Leone
ISSN (Print Edition): 2102-6459
ISSN (Electronic Edition): 2102-6467

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