Branches Of Physics Research Articles

Methodology to Obtain Universal Solutions for Systems of Coupled Ordinary Differential Equations. Examples of a Continuous Flow Chemical Reactor and a Coupled Oscillator

This paper presents a concise and orderly methodology to obtain universal solutions to different problems in science and engineering using the nondimensionalization of the governing equations of the physical–chemical problem posed. For its application, a deep knowledge of the problem is necessary since it will facilitate the adequate choice of the references necessary for its resolution. In addition, the application of the methodology to examples of coupled ordinary differential equations is shown, resulting in an interesting tool to teach postgraduate students in the branches of physics, mathematics, and engineering. The first example used for a system of coupled ordinary differential equations is a model of a continuous flow chemical reactor, where it is worth noting; on the one hand, the methodology used to choose the reference (characteristic) time and, on the other, the equivalence between the characteristic times obtained for each one of the species. The following universal curves are obtained, which are validated by comparing them with the results obtained by numerical simulation, where it stands out that the universal solution includes an unknown that must be previously obtained. The resolution of this unknown implies having a deep knowledge of the problem, a common characteristic when using the methodology proposed in this work for different engineering or physicochemical problems. Finally, the second example is a coupled oscillator, where it is worth noting that the appearance of characteristic periods that implicitly or explicitly affect the particles’ movement is striking.

Particle-continuum duality of skyrmions

Topological solitons are crucial to many branches of physics, such as models of fundamental particles in quantum field theory, information carriers in nonlinear optics, and elementary entities in quantum and classical computations. Chiral magnetic materials are a fertile ground for studying solitons. In the past a few years, a huge number of all kinds of topologically protected localized magnetic solitons have been found. The number is so large, and a proper organization and classification is necessary for their future developments. Here we show that many topological magnetic solitons can be understood from the duality of particle and elastic continuum-medium nature of skyrmions. In contrast to the common belief that a skyrmion is an elementary particle that is indivisible, skyrmions behave like both particle and continuum media that can be tore apart to bury other objects, reminiscing particle-wave duality in quantum mechanics. Skyrmions, like indivisible particles, can be building blocks for cascade skyrmion bags and target skyrmions. They can also act as bags and glues to hold one or more skyrmions together. The principles and rules for stable composite skyrmions are explained and presented, revealing their rich and interesting physics.

Fractional Vector Cross Product in Euclidean 3-Space

In this research a new definition of fractional vector cross product of two vectors in Euclidean 3-space is presented. Using this new definition the formulae for Euclidean norm, fractional triple vector cross product, curl and divergence of fractional vector cross product of an electromagnetic vector field is discussed. In particular cases, all the properties satisfy definition of standard vector cross product for standard orthogonal basis of R3. The new definition has application in radiation characteristic in micro-strip antenna and can be applied in other branches of mathematics and physics.

Hermite–Padé approximation and integrability

We show that solution to the Hermite–Padé type I approximation problem leads in a natural way to a subclass of solutions of the Hirota (discrete Kadomtsev–Petviashvili) system and of its adjoint linear problem. Our result explains the appearance of various ingredients of the integrable systems theory in application to multiple orthogonal polynomials, numerical algorithms, random matrices, and in other branches of mathematical physics and applied mathematics where the Hermite–Padé approximation problem is relevant. We present also the geometric algorithm, based on the notion of Desargues maps, of construction of solutions of the problem in the projective space over the field of rational functions. As a byproduct we obtain the corresponding generalization of the Wynn recurrence. We isolate the boundary data of the Hirota system which provide solutions to Hermite–Padé problem showing that the corresponding reduction lowers dimensionality of the system. In particular, we obtain certain equations which, in addition to the known ones given by Paszkowski, can be considered as direct analogs of the Frobenius identities. We study the place of the reduced system within the integrability theory, which results in finding multidimensional (in the sense of number of variables) extension of the discrete-time Toda chain equations.

Quantum circuit for measuring an operator's generalized expectation values and its applications to non-Hermitian winding numbers

We propose a general quantum circuit based on the swap test for measuring the quantity $\langle \psi_1 | A | \psi_2 \rangle$ of an arbitrary operator $A$ with respect to two quantum states $|\psi_{1,2}\rangle$. This quantity is frequently encountered in many fields of physics, and we dub it the generalized expectation as a two-state generalization of the conventional expectation. We apply the circuit, in the field of non-Hermitian physics, to the measurement of generalized expectations with respect to left and right eigenstates of a given non-Hermitian Hamiltonian. To efficiently prepare the left and right eigenstates as the input to the general circuit, we also develop a quantum circuit via effectively rotating the Hamiltonian pair $(H,-H^\dagger)$ in the complex plane. As applications, we demonstrate the validity of these circuits in the prototypical Su-Schrieffer-Heeger model with nonreciprocal hopping by measuring the Bloch and non-Bloch spin textures and the corresponding winding numbers under periodic and open boundary conditions (PBCs and OBCs), respectively. The numerical simulation shows that non-Hermitian spin textures building up these winding numbers can be well captured with high fidelity, and the distinct topological phase transitions between PBCs and OBCs are clearly characterized. We may expect that other non-Hermitian topological invariants composed of non-Hermitian spin textures, such as non-Hermitian Chern numbers, and even significant generalized expectations in other branches of physics would also be measured by our general circuit, providing a different perspective to study novel properties in non-Hermitian as well as other physics realized in qubit systems.

Achiral and Chiral Optical Force Within Topological Optical Lattices Generated with Plasmonic Metasurfaces and Tunable Incident Beam

An optical lattice is a platform that is used in studies in multiple branches of physics, e.g., ultracold atoms and microfluidic sorting. Unlike traditional complex optical systems, surface plasmon polaritons enable the generation of optical lattices on a chip. Here, we propose an on-chip scheme to transform five topological optical lattices using tunable polarization and a phase vortex. Using the dipolar approximation and numerical simulations, we demonstrate that the spin density force is the main force for sorting chiral particles in the out-of-plane direction when their radius is more than 100 nm. A microflow system is proposed to trap particles with electric optical lattices and sort chiral particles with spin optical lattices. Our findings offer possible routes toward realization of on-chip optical lattices and enable their potential application in both biology and chemistry, e.g., in simultaneous trapping or excitation of multiple objects and identification and sorting of chiral objects.

Finding and improving bounds of real functions by thermodynamic arguments

The possibility of stating the second law of thermodynamics in terms of the increasing behaviour of a physical property establishes a connection between that branch of physics and the theory of algebraic inequalities. We use this connection to show how some well-known inequalities, such as the standard bounds for the logarithmic function or generalizations of Bernoulli's inequality, can be derived by thermodynamic methods. Additionally, we show that by comparing the global entropy production in processes implemented with decreasing levels of irreversibility but subject to the same change of state of one particular system, we can find progressively better bounds for the real function that represents the entropy variation of the system. As an application, some new families of bounds for the function log (1+x) are obtained by this method.

Advances in Physics of Semiconductors

It is my pleasure to write this preface to the Special Section in the May 2023 issue of pss(b), dedicated to the collection of selected works presented during the 35th International Conference on Physics of Semiconductors (ICPS) held in Sydney, Australia in 2022. It was one of the first meetings post the pandemic and it was wonderful to see the community gathering physically together. The ICPS series traditionally encompasses a variety of topics spanning device physics, quantum technologies, spin physics, wide bandgap materials, light–matter interactions, and other branches of materials science, physics and engineering. The collection to follow offers a glimpse into what has been presented, and showcases the excellent science undertaken around the globe. A growing interest in the scientific community is currently evolving around van der Waals crystals, and other two-dimensional systems. It is therefore no surprise, several works focus on these topics – discussing various excitonic, photonic, magnetic, and terahertz properties. Various spin phenomena effects are also discussed in traditional semiconductors such as GaAs/GaN and SiGe. Works on plasmonic gap cavities and electroluminescence as well as theoretical calculations of electronic structures are also included. The ICPS series has been continuously going now for over 70 years, one of the longest running conference series in the world. As we are preparing for the next meeting in Ottawa, Canada, the collection of papers should inspire our junior colleagues, that not only semiconductor physics is here to stay, but in fact, it is a multi-disciplinary and burgeoning field of research.

Direct stress minimization in electro‐mechanical metamaterials

AbstractMetamaterials are artificially created multiscale materials with many different applications [1]. We assume periodic microstructure. No specific length scale is demanded for the differentiation between the scales. Instead, we consider the microscale as consisting of repeating unit cells, whereas the macroscale is the scale, where desired and sometimes unusual physical effects occur. The precise arrangement and geometry at the microscale level is responsible for the macroscopic material behavior, which can substantially differ from the original components it is made from. This way, unique material properties otherwise not found in nature (e.g. negative refractive materials [2]) are possible. Most previous research regarding metamaterials concentrated only on a single physical branch in each case, e.g. electromagnetic or acoustic metamaterials [3,4].In this contribution we present a class of theoretical electro‐mechanical metamaterials by combining insulating and conducting materials. Our aim is to directly control and reduce the resulting total stress of insulating materials by counteracting the mechanical stress through the application of an electric field, which is created by a conducting material. The solution of the resulting minimization problem is related to the eigenvalues of the mechanical stress tensor. Additionally, we discuss the constrained cases of tension and compression and cover the plane stress case. We show numerical results for all cases and discuss the limits of such a material.

Digital Banking through the Uncertain COVID Period: A Panel Data Study

This research investigates how the uncertainty caused by the COVID-19 pandemic has affected digital banking usage in India. The study is made by utilizing a panel of data consisting of 108 firm-month observations during covid period from 2020 to 2022, with data mainly collected to analyze the impact of COVID-19 uncertainty. Most of the determinants were collected from the RBI data website. The main emphasis of this study is on the utilization of digital banking services in the context of the pandemic, and the research assesses the factors that have influenced this trend, including the number of physical bank branches, the utilization of debit and credit cards at automated teller machines (ATMs) and points of sale (PoS), as well as the level of economic policy uncertainty (EPU). The analysis was conducted using panel regression analysis, a suitable method for handling the error components in the model that are either fixed or random. The findings indicate that the uncertainty caused by the pandemic has had a negative impact on the use of digital banking services. Additionally, the study highlights that the usage of debit and credit cards at PoS has significantly contributed to promoting the progress of digital banking services during the pandemic. Overall, this study provides valuable insights into how digital banking services have evolved during a period of significant uncertainty and disruption.

A century of comparative biomechanics: emerging and historical perspectives on an interdisciplinary field.

A century of comparative biomechanics: emerging and historical perspectives on an interdisciplinary field.

A Study on Mobile Banking in Bangladesh

Mobile banking refers to any private or commercial transaction in which a bank or financial institution transfers ownership of or rights to use money (hard or soft), and which is made possible by the use of mobile devices with wireless access technology. It can conduct financial transactions even without a physical branch. Objective: To identify the uses and purpose of Mobile banking systems and share some new concepts regarding Mobile banking system in Bangladesh. Materials and Methods: The necessary data was acquired from people of various ages and evaluated in light of the objectives of the study. The basis for this inquiry was field data. The investigation's principal sampling technique was cluster sampling. 120 respondents were interviewed in various locations around Dhaka city using both primary and secondary sources. Secondary data were used to give the study topic's theoretical perspective. Using column charts, the data analysis has been graphically presented. The data was analyzed using Microsoft Word and Excel. Results: The majority of respondents (82.1%) are in the 20–30 age bracket. According to the findings, young people and adults prefer using e-banking and e-payment services the most. About 72.1% of the respondents are service holder followed by 18.6% are students. 22% of respondents utilize rocket, followed by 58% who use Bkash. The majority of respondents (78%) only use mobile banking for personal purchases. Conclusion: The billion individuals globally without bank accounts who use mobile banking may find it to be a strong method to conduct cashless transactions.

Effects of Computer-Mediated Instruction (Cmi) on Student-Teachers’ Misconceptions and Achievement in Physics

Physics is one of the natural sciences taught in Colleges of Education in Nigeria as a teaching subject with course units in line with the branches of physics, such as mechanics, thermodynamics, electromagnetism, optics, acoustics, astronomy and electronics. These course units are generally taught using the traditional lecture approach which neither give students opportunity to participate actively in the learning process nor co-construct knowledge as required in a science classroom. Consequently, students struggle with misconceptions which lead to poor academic achievement in physics. This study investigated the effects of computer-mediated instruction (CMI) on physics student-teachers’ misconceptions and achievement in Federal Colleges of Education, South-South Zone, Nigeria. The study adopted pretest-posttest one control group quasi-experimental design with intact classes. The study population comprised 51 physics student-teachers from the three federal colleges of education in the South-South zone of Nigeria who registered for Mechanics and Properties of Matter II during the 2018/2019 academic session. Simple random sampling technique was use to select the two federal colleges of education that participated in the study. Data were collected using Mechanics and Properties of Matter Misconceptions and Achievement Test (MPMMAT). Descriptive and inferential statistics were used for analysis with the assistance of Statistical Package for Social Sciences (SPSS) version 23.0 software. Result findings showed that Physics students hold a number of misconceptions on Mechanics and Properties of Matter II. Results equally revealed that CMI can improve students’ achievement in Mechanics and Properties of Matter II and can also reduce their misconceptions in the course. The study concluded that computer-mediated instruction (CMI) is an effective teaching approach which can reduce physics student-teachers’ misconceptions in mechanics and improve their academic achievement.

The Thermo-field Dynamics Method for Electron with Two-mode Electromagnetic Field

The quick progress in quantum entanglement research allows us not one to study quantum systems down to N-bodies but also to take a new look at these systems in different branches of physics; particularly the statistical thermodynamics where the application of the thermo-field dynamics (<I>TFD</I>) method to the investigation of entanglement is fruitful. Because the traditional methods based on the identification of a specific parameter show their limit. The process using (<I>TFD</I>) facilitates the understanding of entanglement because it focuses directly on the eigenstate of the system and it is useful in the equilibrium and the non-equilibrium states also. In this context, the (<I>TFD</I>) method is used in this paper to analyze entanglement of an electron interacting with a two-mode electromagnetic field assimilated to an electron with two harmonic oscillators. Entanglement entropies are derived between concerned, not concerned harmonic oscillator and electron compute when the system is in a thermodynamic equilibrium and non-equilibrium state. For the equilibrium case, an increase in the number of particles per unit volume increases the quantum entanglement consequently entanglement appears more important for the couple oscillator-electron than the one electron, this trend is reversed for the non-equilibrium case. By respecting the entanglement parameters, such results allow us to know the relative equilibrium state of the overall system.

Analytical solitary wave solutions of a time-fractional thin-film ferroelectric material equation involving beta-derivative using modified auxiliary equation method

The main objective of current paper is to examine the impacts of fractional parameters on the dynamic response of soliton waves in a nonlinear time-fractional thin-film ferroelectric materials equation (TFFEME). To achieve such a goal, the TFFEME is first rehabilitated into ordinary differential equation using a complex wave transformation. Solitary wave solutions of the governing equation, representing the dynamics of waves in the material and plays a vital rule in many branches of physics and hydrodynamics, are then constructed through applying the modified auxiliary equation method (MAEM). The extracted solutions are demonstrated using definition of the beta derivative to understand their dynamical behavior. The hyperbolic, periodic and trigonometric function solutions are used to derive the analytical solutions for the given model. As a result, dark, bright, periodic and solitary wave solitons are obtained. The fractional impact of the above derivative on the physical phenomena is observed. The 2D and 3D graphs are also shown to confirm the behavior of analytical wave solutions.

Study on the Space Geodesy

Geodesic is a kind of shortest path among all curves in a metric space, which originally appeared in the Gaussian period. Since then, it was extensively applied in various branches of mathematics and physics, such as Riemannian geometry, digital geometry, Einstein’s relativity, etc. This thesis mainly discusses geodesic definitions in Euclidean space and those in smooth manifolds after introducing the basic theory of smooth manifolds. At first, the thesis applies three ways to define geodesics on a surface, including the geodesic curvature method, the shortest distance method, and the relation of the principal normal of a curve and the normal vector of a surface. Then, the paper introduces some basic concepts in Riemannian manifolds. Finally, it gives a general definition of geodesics in a smooth Riemannian manifold.

EFOMP policy statement 17: The role and competences of medical physicists and medical physics experts in the different stages of a medical device life cycle

MPPs are trained in the branches of physics associated with the practice of medicine. Possessing a solid scientific background and technical skills, MPPs are well suited to play a leading role within each stage of a medical device life cycle. The various stages of the life cycle of a medical device include establishment of requirements with use-case assessment, investment planning, procurement of medical devices, acceptance testing especially regarding safety and performance, quality management, effective and safe use and maintenance, user training, interfacing with IT systems, and safe decommissioning and removal of the medical devices. Acting as an expert within the clinical staff of a healthcare organisation, the MPP can play an important role to achieve a balanced life cycle management of medical devices. Given that the functioning of medical devices and their clinical application in routine clinical practice and research is heavily physics and engineering based, the MPP is strongly associated with the hard science aspects and advanced clinical applications of medical devices and associated physical agents. Indeed, this is reflected in the mission statement of MPP professionals [1]. PurposeThe life cycle management of medical devices is described as well as the procedures involved. These procedures are performed by multi-disciplinary teams within a healthcare environment. The task of this workgroup was focused on clarifying and elaborating the role of the Medical Physicist and Medical Physics Expert - here collectively referred to as the Medical Physics Professional (MPP) - within these multi-disciplinary teams. This policy statement describes the role and competences of MPPs in every stage of a medical device life cycle. If MPPs are an integral part of these multi-disciplinary teams, the effective use, safety, and sustainability of the investment is likely to improve as well as the overall service quality delivered by the medical device during its life cycle. It leads to better health care quality and reduced costs. Furthermore, it gives MPPs a stronger position in health care organisations throughout Europe.

Certain Properties and Applications of Δh Hybrid Special Polynomials Associated with Appell Sequences

The development of certain aspects of special polynomials in line with the monomiality principle, operational rules, and other properties and their aspects is obvious and indisputable. The study presented in this paper follows this line of research. By using the monomiality principle, new outcomes are produced, and their differential equation and series representation is obtained, which are important in several branches of mathematics and physics. Thus, in line with prior facts, our aim is to introduce the Δh hybrid special polynomials associated with Hermite polynomials denoted by ΔhHQm(u,v,w;h). Further, we obtain some well-known main properties and explicit forms satisfied by these polynomials.

Polymers and rheology: A tale of give and take

Polymers and rheology were both born in the twenties of the last century, fruit of the disruptive and creative scientific atmosphere of this decade. The development of polymer science and technology in the last almost 100 years has been colossal, whereas rheology has been able to create its own route as a branch of Physics. In this review paper we describe the interactions between both scientific areas, demonstrating that many of the crucial aspects for the progress of one of them owes to contribution of the other and viceversa. This interrelationship is shown through a historical survey of the principal milestones, starting from the correlation of the molecular weight with the intrinsic viscosity. A pondered analysis of the contributions of rheology to polymer science and technology, lead us to assert that the role of the former is rather founded on 50 years old discoveries.

Review of true tales of medical physics: Insights into a life‐saving specialty, edited by Jacob Van Dyk

Review of true tales of medical physics: Insights into a life‐saving specialty, edited by Jacob Van Dyk