EPJ ST issue: Trends in Recurrence Analysis of Dynamical Systems
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- Published on 08 March 2023

More than a decade has passed since the publication of the special issue “20 Years of Recurrence Plots: Perspectives for a Multi-purpose Tool of Nonlinear Data Analysis” in the European Physical Journal—Special Topics (EPJST). The hope for further developments inspired by the interesting contributions in this special issue was fully realized. We see an amazing development in the field of recurrence plots (RPs), recurrence quantification analysis (RQA), and recurrence networks. Recurrence analysis is not just one method; it has emerged as an entire framework with many extensions, special recurrence definitions, and specifically designed methods and tools. It has found spreading applications in diverse and growing scientific fields. Recurrence analysis has become a widely accepted concept, even referred to in studies that are actually not using it as a method, but rather using it as a reference or alternative tool. It continues to be an active area of research and development today. An attempt to provide an overview of the most significant technical developments of this recurrence-plot-based framework in the past decade is included in this special issue.
All articles are available here and are freely accessible until 8 May 2023. For further information read the Editorial by Norbert Marwan, Charles L. Webber & Andrzej Rysak ”Trends in recurrence analysis of dynamical systems” Eur. Phys. J. Spec. Top. 232, 1–3 (2023). https://doi.org/10.1140/epjs/s11734-023-00766-z.
EPJ ST Highlight - Tracking how magnetism affects animal behaviour
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- Published on 23 February 2023

We still know little about how animal behaviour changes in response to magnetic fields. A new review provides a tutorial introduction to the study of this fascinating and potentially useful phenomenon.
For over 50 years, scientists have observed that the behaviour of a wide variety of animals can be influenced by the Earth’s magnetic field. However, despite decades of research, the exact nature of this ‘magnetic sense’ remains elusive. Will Schneider and Richard Holland from Bangor University in Wales and their co-worker Oliver Lindecke from the Institute for Biology, Oldenburg, Germany have now written a comprehensive overview of this cross-disciplinary field, with an emphasis on the methodology involved. This work is now published in EPJ ST.
EPJ ST issue: Collective behavior of nonlinear dynamical oscillators
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- Published on 16 January 2023

This topical issue collects contributions of recent achievements and scientific progress related to the collective behavior of nonlinear dynamical oscillators. The individual papers focus on different questions of present-day interest in this topic.
All articles are available here and are freely accessible until 16 March 2023. For further information read the Editorial by Sajad Jafari, Bocheng Bao, Christos Volos, Fahimeh Nazarimehr & Han Bao ”Collective behavior of nonlinear dynamical oscillators” Eur. Phys. J. Spec. Top. 231, 3957–3960 (2022). https://doi.org/10.1140/epjs/s11734-022-00725-0
EPJ ST Highlight - Dynamics of the COVID-19 pandemic
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- Published on 13 January 2023

The outbreak of COVID-19 changed the human perception of day-to-day life and tested the bounds of medical technology in protecting the welfare of humans. Several approaches and safety measures have been implemented to minimize the countless lives that are being affected. However, public health and educational breaches are evidenced in most countries in which not all citizens have the same opportunities to deal with the pandemic. Therefore, this has led to pervasive consequences, including mental health problems because of the disruption of everyday life routines.
This special issue is a collection of 35 orginal research articles that address the dynamics and applications of COVID-19 through nonlinear dynamics. The articles are organized in five sections, comprising mathematical modeling and epidemics, the dynamics of several waves and transmission, neural network and deep learning related to COVID-19, predictions and estimations related to COVID-19, and detailed analysis on the pandemic and its applications. The various contributions report important, timely, and promising results and provide insight into the spread of the coronavirus and control measures against the COVID-19 pandemic.
All articles are available here and are freely accessible until 21 March 2023. For further information read the Editorial by Santo Banerjee ”Dynamics of the COVID-19 pandemic: nonlinear approaches on the modelling, prediction and control” Eur. Phys. J. Spec. Top. 231, 3275–3280 (2022). https://doi.org/10.1140/epjs/s11734-022-00724-1
EPJ ST Highlight - Showcasing the possibilities of memristor circuits
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- Published on 13 January 2023

The papers presented in this special issue explore several unique capabilities of memristor-based systems: including multistability, nonlinearity, and chaotic dynamics
First demonstrated in 2008, the memristor is an electrical component which can limit the amount of current in a circuit, while remembering the amount of charge it conveyed in the past. Yet despite its numerous potential applications, the memristor’s commercial rollout has so far been restricted by the high manufacturing costs of its nano-scale electrical components.
To improve both the range of applications and theoretical understanding of memristors, there is a need to investigate their fundamental features, while diversifying the tools used to model their behaviours. In this special issue, the journal EPJ ST presents 25 new papers showcasing the widely-varied possibilities by memristor systems, and the mathematical principles required to understand and model them.
EPJ ST Editor Peter Hänggi awarded 2023 APS Lars Onsager Prize
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- Published on 28 November 2022

The American Physical Society awards the prestigious Lars Onsager Prize every year to one or several individuals for outstanding research in theoretical statistical physics including the quantum fluids. Professor Peter Hänggi, Universität Augsburg, Germany, Editor of EPJ ST, former Editor-in-Chief of EPJ B and 2007 Chairperson of the EPJ Scientific Advisory Committee receives the 2023 APS Lars Onsager Prize "for the development of Brownian motors and pioneering contributions to nonequilibrium statistical physics, relativistic and quantum thermodynamics."
EPJ ST Highlight - Elastic nozzles could create more stable liquid jets
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- Published on 27 September 2022

New experiments show that nozzles which deform as liquid flows through them could help to improve the stability of liquid jets in many different scenarios
When a liquid jet is squirted through a nozzle, it will eventually break up into a string of droplets. Through previous studies, researchers determined that the distance from the nozzle where this breakup occurs depends on a wide range of factors: including the nozzle’s shape, and the movement of air surrounding the jet. So far, however, little attention has been paid to elastic nozzles, which can deform as liquids pass through them. Through new research published in EPJ ST, a team led by Andrew Dickerson at the University of Tennessee, USA, introduces the concept of passively-deforming nozzles, and shows that softer nozzle materials can produce more stable jets across a wide range of flow rates.
EPJ ST Highlight - Tiny animal hairs could act as sensitive compass needles
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- Published on 20 September 2022

Statistical mechanics shows that some animals may be able to perceive Earth’s magnetic field with bundles of microscopic hairs in their inner ears.
The exact mechanisms animals use to sense the direction of Earth’s magnetic field have long remained a mystery. One leading theory suggests that this ability is tied to bundles of microscopic hair cells in the inner ears. Through new research published in EPJ ST, Kirill Kavokin at St Petersburg State University, Russia, uses statistical analysis to show that just around 100 of these hair cells could act as effective biological compass needles, allowing animals to accurately sense the magnetic field surrounding them.
EPJ ST Highlight - Chaotic circuit exhibits unprecedented equilibrium properties
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- Published on 26 July 2022

Mathematical derivations have unveiled a chaotic, memristor-based circuit in which different oscillating phases can co-exist along 6 possible lines.
Unlike ordinary electronic circuits, chaotic circuits can produce oscillating electrical signals which never repeat over time – but nonetheless, display underlying mathematical patterns. To expand the potential applications of these circuits, previous studies have designed systems in which multiple oscillating phases can co-exist along mathematically-defined ‘lines of equilibrium.’ In new research published in EPJ ST, a team led by Janarthanan Ramadoss at the Chennai Institute of Technology, India, designed a chaotic circuit with six distinct lines of equilibrium – more than have ever been demonstrated previously.
EPJ ST Highlight - The fascinating ways animals navigate
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- Published on 30 June 2022

Many animals – from birds to whales to zebras – find their way across great distances using a variety of environmental factors.
The Arctic Tern migrates an extraordinarily long way – from pole to pole. And while this bird is unique in the distance it traverses, its excellent sense of direction is shared by many other animals that use a variety of environmental factors to optimise their routes. In a new review paper in EPJ ST, Roswitha and Wolfgang Wiltschko from the Goethe-Universität in Frankfurt am Main, Germany, outline how animals use internal compasses to navigate and the mechanisms they are likely to use to determine the direction of their destination. These can be applied when developing effective navigation systems for robots.