EPJ Plus Focus Point on Modified Gravity Theories and Cosmology
- Details
- Published on 30 September 2021
This focus point issue of European Physical Journal Plus (EPJ Plus) aims to reflect the diversity of modified gravity theories and of their applications to the cosmological problem. The scope of the covered topics is enough broad, ranging from teleparallel gravity and gravitino problem in extended gravity up to traversable wormholes in f(R) gravity, from a model of lattice universe, up to addressing the Hubble tension within modified gravity. There are also papers dealing with modified gravity tests, namely, with Lense–Thirring precession, with observational constraints, including the black hole shadow, with the Solar system constraints to Brans–Dicke and Palatini f(R) theories, as well as with suggestions for high-precision gravitational redshift measurements as probes for gravity theories.
This collection also indicates that the modified gravity and cosmology are widely developing areas being in permanent contact with ongoing observational surveys and experimental programs.
All articles are available here and are freely accessible until 28th November 2021. For further information read the Editorial
EPJ Plus Highlight - Beer mats make bad frisbees and why it matters
- Details
- Published on 05 August 2021
Whilst modelling the forces acting upon a thrown beer mat, physicists discover why flat discs have such poor flight potential.
The question ‘Why do beer mats make bad frisbees?’ may initially seem like something of an odd inquiry to spark research. Yet, by considering the physical properties of such a common everyday item, physicists can create models that also describe the behaviours of a wide range of objects. In a new paper published in EPJ Plus, Johann Ostmeyer, the University of Bonn, Germany, and his co-authors look at the dynamics that give beer mats poor fight potential.
EPJ Plus Focus Point on Light Pressure across All Scales
- Details
- Published on 01 July 2021
This focus point issue of European Physical Journal Plus (EPJ Plus) finds its inspiration in the huge number of applications of light pressure across all scales of Nature, from space to nanoscience and atomic physics. Together this issue features 11 papers, including both experimental and theoretical works, which span a wide range of activities. These also include 3 review papers on the theory and practice of optical tweezers, its application in single molecule experiments and in the study of critical Casimir forces.
EPJ Plus Focus Point on Classical and Quantum Information Geometry
- Details
- Published on 25 May 2021
What is information? What can we do with information? How are we supposed to understand information? How does information influence the development of modern Science?
Some, if not all and a thousand more, of these questions come to the mind of almost every modern researcher whose research area is somehow interconnected with Information Theory. However, the answers to these questions are far from being completely unravelled, and some recent theoretical developments seem to suggest that our understanding of the geometrical aspects of Information Theory will play an increasingly important role in the quest for answers.
EPJ Plus Highlight - Understanding the mechanism that gives light a ‘little extra push’
- Details
- Published on 07 May 2021
The use of light to move matter has a wide range of technological applications and could one day even power spaceflight. New research suggests a method to better understand this subtle phenomenon.
We are all familiar with the sight of a white pool ball striking a red and smoothly transferring its momentum. What is less familiar is that light can also transfer momentum and is even able to give objects a tiny push. A new paper published in EPJ Plus suggests a way to examine the mechanism behind light’s subtle momentum transfer — the Poynting vector. The paper is the work of Manuel Marqués of IFIMAC-The Condensed Matter Physics Center, and the Nicolás Cabrera Institute (INC), Universidad Autónoma de Madrid, Spain, and Shulamit Edelstein and Pedro Serena from the Spanish National Research Council (CSIC).
EPJ Plus Highlight - A deeper understanding of how cells move and stick together
- Details
- Published on 06 May 2021
The way cells adhere to surfaces is an important element in allowing them to form cohesive tissues. A new study looks at how cells stick to a surface and spread across it.
Observing how cells stick to surfaces and their motility is vitally important in the study of tissue maintenance, wound healing and even understanding how cancers progress. A new paper published in EPJ Plus, by Raj Kumar Sadhu, Weizmann Institute of Science, Rehovot, Israel, takes a step towards a deeper understanding of these processes.
EPJ Plus Focus Point on Cancer & HIV/AIDS Dynamics: From Optimality to Modelling
- Details
- Published on 19 March 2021
This Focus Point covers twelve original papers obtained from advanced theoretical analysis, experimental, and numerical simulations in Cancer and HIV/AIDS research. Results include a randomized discrete logistic equation to describe the dynamics of breast tumor; a mathematical model of breast cancer involving a system of differential equations with piecewise constant arguments to analyze the tumor growth and chemotherapeutic treatment; a new stochastic HIV mathematical model; incorporation of the Beddington–DeAngelis incidence rate to a continuous-time HIV infection model with cure rate and full logistic proliferation; a model for the tumor and normal cell growth under the influence of carcinogenic agents, an immunomodulator and variable influx of immune cells; a within-host HIV dynamical model under the effect of cytotoxic T lymphocytes immune response; the study of the interaction between drug addiction and the contagion of HIV/AIDS; a system of fractional differential equations with delays and a new computational method based on hybrid functions and Legendre polynomials with application to immunodeficiency viruses systems; investigation of cervical cancer; an HIV/AIDS epidemic model under fractal-fractional-order derivatives; study of the dynamics of HIV-AIDS infection via a fractional order SICA system; and sufficient conditions for the stability of a system describing the growth of malignant tumors.
EPJ Plus Highlight - A full-scale prototype for muon tomography
- Details
- 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 Plus Focus Point on Solitons, Integrability, Nonlinear Waves: Theory and Applications
- Details
- Published on 15 January 2021
Nonlinear waves have long been at the research focus of both physicists and mathematicians, in diverse settings ranging from electromagnetic waves in nonlinear optics to matter waves in Bose-Einstein condensates, from Langmuir waves in plasma to internal and rogue waves in hydrodynamics. The study of physical phenomena by means of mathematical models often leads to nonlinear evolution equations known as integrable systems. One of the distinguished features of integrable systems is that they admit soliton solutions, i.e., stable, localized traveling waves which preserve their shape and velocity in the interaction. Other fundamental properties are their universal nature, and the fact that they can be effectively linearized, e.g., via the inverse scattering transform, or reduced to appropriate Riemann-Hilbert problems. Moreover, solutions can often be derived by the Zakharov-Shabat dressing method, by Backlund or Darboux transformations, or by Hirota’s method. Prototypical examples of such integrable equations in 1+1 dimensions are the nonlinear Schrödinger equation and its multicomponent generalizations, the sine-Gordon equation, the Korteweg-de Vries and the modified KdV equations, etc. In 2+1 dimensions the most notable examples are the Kadomtsev-Petviashvili (KP) equations, and the Davey-Stewartson equations. The aim of this special issue is to present the latest developments in the theory of nonlinear waves and integrable systems, and their various applications.
EPJ Plus Highlight - Understanding electron transport in graphene nanoribbons
- Details
- Published on 10 September 2020
New understanding of the electrical properties of graphene nanoribbons (GRBs), when bounded with aromatic molecules, could have significant benefits in the development of chemosensors and personalised medicine.
Graphene is a modern wonder material possessing unique properties of strength, flexibility and conductivity whilst being abundant and remarkably cheap to produce, lending it to a multitude of useful applications – especially true when these 2D atom-thick sheets of carbon are split into narrow strips known as Graphene Nanoribbons (GNRs). New research published in EPJ Plus, authored by Kristiāns Čerņevičs, Michele Pizzochero, and Oleg V. Yazyev, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, aims to better understand the electron transport properties of GNRs and how they are affected by bonding with aromatics. This is a key step in designing technology such chemosensors.
