- Published on 09 August 2023
Through a new survey, researchers show how mathematical representations named ‘tensor trains’ can help to capture and simulate the dynamics of evolving quantum systems across a range of different scenarios.
Many quantum systems are heavily influenced by their surrounding environments, making them incredibly challenging to describe theoretically. To capture the dynamics and evolution of these systems, researchers often use mathematical representations named ‘tensor trains’. Through new research published in EPJ ST, a team of researchers from four different institutions in France show how tensor trains can be implemented to describe and simulate quantum systems.
- Published on 01 August 2023
Thermal field theory seeks to explain many-body dynamics at non-zero temperatures not considered in conventional quantum field theory.
Quantum field theory is a framework used by physicists to describe a wide range of phenomena in particle physics and is an effective tool to deal with complicated many-body problems or interacting systems.
Conventional quantum field theory describes systems and interactions at zero temperature and zero chemical potential, and interactions in the real world certainly do occur at non-zero temperatures. That means scientists are keen to discover what effects may arise as a result of non-zero temperature and what new phenomena could arise due to a thermal background. In order to understand this, physicists turn to a recipe for quantum field theory in a thermal background — thermal field theory.
In a new paper in EPJ ST, Munshi G. Mustafa, Senior Professor at the Saha Institute of Nuclear Physics, Kolkata, India, introduces a thermal field theory in a simple way weaving together the details of its mathematical framework and its application.
- Published on 27 July 2023
Researchers have explored the evolution of systems of interacting spins, as they transition from random to orderly alignments. Through new simulations, they show that this evolution can be investigated by measuring the changing strength of the system’s magnetism.
The Ising model describes systems of interacting atomic spins relaxing from a ‘paramagnetic’ state – whose spins point in random directions, to a ‘ferromagnetic’ state – whose spins spontaneously align with each other. So far, the nonequilibrium dynamics of this transition has been studied by measuring the growth of regions, or ‘domains’ of aligned spins. In new research published in EPJ ST, researchers led by Wolfhard Janke at the University of Leipzig, Germany, show how this can be done far more easily by measuring the strength of the system’s magnetisation. The team’s discovery could help researchers to better understand the atomic-scale interactions underlying many different phenomena in nature: from electrostatic forces, to neuroscience and economics.
- 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.
- 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.
- 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
- 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
- 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.
- 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."
- 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.