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EPJ D Highlight - Investigating dense plasmas with positron waves
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- Published on 19 February 2021
Astrophysical and lab-created plasmas under the influence of magnetic fields are the source of intense study. New research seeks to understand the dynamics of position waves travelling through these clouds of highly ionised gas.
The investigation of Electron-Positron-Ion (EPI) plasma — a fully ionised gas of electrons and positrons that includes astrophysical plasmas like solar winds — has attracted a great deal of attention over the last twenty years. A new study published in EPJ D by Garston Tiofack, Faculty of Sciences, University of Marousa, Cameroon, and colleagues, assesses the dynamics of positron acoustic waves (PAWS) in EPI plasmas whilst under the influence of magnetic fields, or magnetoplasmas.
EPJ C Highlight - Placing cosmological constraints on quantum gravity phenomenology
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- Published on 09 February 2021
Researchers have used cosmological data to place stringent new limits on a model which emerges in attempts to reconcile gravity with the principles of quantum mechanics.
A description of gravity compatible with the principles of quantum mechanics has long been a widely pursued goal in physics. Existing theories of this ‘quantum gravity’ often involve mathematical corrections to Heisenberg’s Uncertainty Principle (HUP), which quantifies the inherent limits in the accuracy of any quantum measurement. These corrections arise when gravitational interactions are considered, leading to a ‘Generalized Uncertainty Principle’ (GUP). Two specific GUP models are often used: the first modifies the HUP with a linear correction, while the second introduces a quadratic one. Through new research published in EPJ C, Serena Giardino and Vincenzo Salzano at the University of Szczecin in Poland have used well-established cosmological observations to place tighter constraints on the quadratic model, while discrediting the linear model.
EPJ B Highlight - Modelling the brain during pain processing
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- Published on 02 February 2021
Novel approaches in graph theory have enabled researchers to reveal the characteristic configurations of neurons which arise as our brains process pain
The many different sensations our bodies experience are accompanied by deeply complex exchanges of information within the brain, and the feeling of pain is no exception. So far, research has shown how pain intensity can be directly related to specific patterns of oscillation in brain activity, which are altered by the activation and deactivation of the ‘interneurons’ connecting different regions of the brain. However, it remains unclear how the process is affected by ‘inhibitory’ interneurons, which prevent chemical messages from passing between these regions. Through new research published in EPJ B, researchers led by Fernando Montani at Instituto de Física La Plata, Argentina, show that inhibitory interneurons make up 20% of the circuitry in the brain required for pain processing.
EPJ A Highlight - Paving the way for effective field theories
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- Published on 01 February 2021
A detailed analysis of theories which approximate the underlying properties of physical systems could lead to new advances in studies of low-energy nuclear processes
Over the past century, a wide variety of models have emerged to explain the complex behaviours which unfold within atomic nuclei at low energies. However, these theories bring up deep philosophical questions regarding their scientific value. Indeed, traditional epistemological tools have been rather elaborated to account for a unified and stabilised theory rather than to apprehend a plurality of models. Ideally, a theory is meant to be reductionist, unifying and fundamentalist. In view of the intrinsic limited precision of their prediction and of the difficulty in assessing a priori their range of applicability, as well as of their specific and disconnected character, traditional nuclear models are necessarily deficient when analysed by means of standard epistemological interpretative frameworks.
EPJ Plus Highlight - A full-scale prototype for muon tomography
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- Published on 29 January 2021
Building on previous studies of muon tomography techniques, this topical issue demonstrates a full-scale prototype for the technology, capable of determining the position of a small lead block within a large sensing area
Each year, billions of tons of goods are transported globally using cargo containers. Currently, there are concerns that this immense volume of traffic could be exploited to transport illicit nuclear materials, with little chance of detection. One promising approach to combating this issue is to measure how goods interact with charged particles named muons – which form naturally as cosmic rays interact with Earth’s atmosphere. Studies worldwide have now explored how this technique, named ‘muon tomography,’ can be achieved through a variety of detection technologies and reconstruction algorithms. In this article of EPJ Plus, a team headed by Francesco Riggi at the University of Catania, Italy, build on these results to develop a full-scale muon tomograph prototype.
EPJ B Colloquium - Record dynamics of evolving metastable systems: theory and applications
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- Published on 29 January 2021
Microscopically very different physical, biological and cultural systems all evolve through a sequence of stages, each characterized by stationary fluctuations around constant values of relevant macroscopic observables. Sudden and rapid changes, called quakes, induce transitions from one stage to the next and reveal the non-equilibrium nature of the dynamics. The duration of the stages increases over time, producing a multi-scaled dynamical behavior known in physics under the name of ``physical aging'', and rooted in all cases in a hierarchically structured underlying configuration space. Record Dynamics (RD) is a coarse-graining approach treating the staged evolution of complex metastable systems with the same statistical tools. This colloquium paper reviews RD methods and ideas that have gradually evolved over time and shows how RD can be applied to selected cases of biological and physical origin. The main property described is that quakes are a log-Poisson process and that the coarse-grained dynamics is therefore log-time homogeneous. The bibliography points the interested reader to the original RD papers and their background.
EPJ D Topical review - A review of the gas and liquid phase interactions in low-temperature plasma jets used for biomedical applications
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- Published on 29 January 2021
Atmospheric pressure plasma jets generated using noble gases have been the focus of intense investigation for over two decades due to their unique physicochemical properties and their suitability for treating living tissues to elicit a controlled biological response. Such devices enable the generation of a non-equilibrium plasma to be spatially separated from its downstream point of application, simultaneously providing inherent safety, stability and reactivity. Underpinning key plasma mediated biological applications are the reactive oxygen and nitrogen species (RONS) created when molecular gases interact with the noble gas plasma, yielding a complex yet highly reactive chemical mixture. The interplay between the plasma physics, fluid dynamics and plasma chemistry ultimately dictates the chemical composition of the RONS arriving at a biological target.
EPJ ST Highlight - GEFS: Searching beyond seismology for earthquake precursors
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- Published on 22 January 2021
A proposed collaborative initiative involving researchers in a wide range of fields could lead to better predictions of large-scale seismic events.
To predict when earthquakes are likely to occur, seismologists often use statistics to monitor how clusters of seismic activity evolve over time. However, this approach often fails to anticipate the time and magnitude of large-scale earthquakes, leading to dangerous oversights in current early-warning systems. For decades, studies outside the seismology field have proposed that these major, potentially devastating seismic events are connected to a range of non-seismic phenomena – which can be observed days or even weeks before these large earthquakes occur. So far, however, this idea hasn’t caught on in the wider scientific community. In this special issue, EPJ Special Topics proposes the Global Earthquake Forecasting System (GEFS): the first collaborative initiative between multi-disciplinary researchers devoted to studying a diverse array of non-seismic earthquake precursors.
EPJD has appointed new Editor-in-Chief Almut Beige
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- Published on 19 January 2021
The publishers of European Physical Journal D: Atomic, Molecular, Optical and Plasma Physics are delighted to announce the appointment of a new Editor-in-Chief, Dr Almut Beige, Head of the Theoretical Physics Group at the University of Leeds, UK, effective January 2021. She will be responsible for the fields of photonics, quantum optics and quantum information of the journal, and succeeds Prof Tommaso Calarco, who steps down after three years in this role.
Dr Almut Beige is an expert in Quantum Optics and Quantum Photonics. Since completing her PhD in Goettingen, she has been fascinated with the often very strange implications of quantum physics. Applications of her research range from quantum computing to quantum metrology and quantum sensing. She has been a member of the Editorial Board for EPJD since 2015.
EPJ C Highlight - Tracking the evolution Maxwell knots
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- Published on 15 January 2021
New research investigates the properties of particular solutions of Maxwell equations, tracking their evolution over time and determining a route to combine them with other systems.
Maxwell equations govern the evolution of electromagnetic fields with light being a particular solution of these equations in spaces devoid of electric charge. A new study published in EPJ C by Alexei Morozov and Nikita Tselousov, from the Moscow Institute of Physics and Technology and the Institute of Transmission Problems, Russia, respectively, details peculiar solutions to the Maxwell equations—so-called Maxwell knots. The research could have applications in the fields of mathematical physics and string theory.
