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Gerard 't Hooft et al 2024 Phys. Scr. 99 052501
S B Dugdale 2016 Phys. Scr. 91 053009
The concept of the Fermi surface is at the very heart of our understanding of the metallic state. Displaying intricate and often complicated shapes, the Fermi surfaces of real metals are both aesthetically beautiful and subtly powerful. A range of examples is presented of the startling array of physical phenomena whose origin can be traced to the shape of the Fermi surface, together with experimental observations of the particular Fermi surface features.
Gerianne Alexander et al 2020 Phys. Scr. 95 062501
Sounds of Science is the first movement of a symphony for many (scientific) instruments and voices, united in celebration of the frontiers of science and intended for a general audience. John Goodenough, the maestro who transformed energy usage and technology through the invention of the lithium-ion battery, opens the programme, reflecting on the ultimate limits of battery technology. This applied theme continues through the subsequent pieces on energy-related topics—the sodium-ion battery and artificial fuels, by Martin Månsson—and the ultimate challenge for 3D printing, the eventual production of life, by Anthony Atala. A passage by Gerianne Alexander follows, contemplating a related issue: How might an artificially produced human being behave? Next comes a consideration of consciousness and free will by Roland Allen and Suzy Lidström. Further voices and new instruments enter as Warwick Bowen, Nicolas Mauranyapin and Lars Madsen discuss whether dynamical processes of single molecules might be observed in their native state. The exploitation of chaos in science and technology, applications of Bose–Einstein condensates and the significance of entropy follow in pieces by Linda Reichl, Ernst Rasel and Roland Allen, respectively. Mikhail Katsnelson and Eugene Koonin then discuss the potential generalisation of thermodynamic concepts in the context of biological evolution. Entering with the music of the cosmos, Philip Yasskin discusses whether we might be able to observe torsion in the geometry of the Universe. The crescendo comes with the crisis of singularities, their nature and whether they can be resolved through quantum effects, in the composition of Alan Coley. The climax is Mario Krenn, Art Melvin and Anton Zeilinger's consideration of how computer code can be autonomously surprising and creative. In a harmonious counterpoint, his 'Guidelines for considering AIs as coauthors', Roman Yampolskiy concludes that code is not yet able to take responsibility for coauthoring a paper. An interlude summarises a speech by Zdeněk Papoušek. In a subsequent movement, new themes emerge as we seek to comprehend how far we have travelled along the path to understanding, and speculate on where new physics might arise. Who would have imagined, 100 years ago, a global society permeated by smartphones and scientific instruments so sophisticated that genes can be modified and gravitational waves detected?
Jack Smith 2022 Phys. Scr. 97 122001
First conceptualised in Olaf Stapledon's 1937 novel 'Star Maker', before being popularised by Freeman Dyson in the 1960s, Dyson Spheres are structures which surround a civilisation's sun to collect all the energy being radiated. This article presents a discussion of the features of such a feat of engineering, reviews the viability, scale and likely design of a Dyson structure, and analyses details about each stage of its construction and operation. It is found that a Dyson Swarm, a large array of individual satellites orbiting another celestial body, is the ideal design for such a structure as opposed to the solid sun-surrounding structure which is typically associated with the Dyson Sphere. In our solar system, such a structure based around Mars would be able to generate the Earth's 2019 global power consumption of 18.35 TW within fifty years once its construction has begun, which itself could start by 2040 using biennial launch windows. Alongside a 4.17 km2 ground-based heliostat array, the swarm of over 5.5 billion satellites would be constructed on the surface of Mars before being launched by electromagnetic accelerators into a Martian orbit. Efficiency of the Dyson Swarm ranges from 0.74–2.77% of the Sun's 3.85 × 1026 W output, with large potential for growth as both current technologies improve, and future concepts are brought to reality in the time before and during the swarm's construction. Not only would a Dyson Swarm provide a near-infinite, renewable power source for Earth, it would also allow for significant expansions in human space exploration and for our civilisation as a whole.
Anton Zeilinger 2017 Phys. Scr. 92 072501
The quantum physics of light is a most fascinating field. Here I present a very personal viewpoint, focusing on my own path to quantum entanglement and then on to applications. I have been fascinated by quantum physics ever since I heard about it for the first time in school. The theory struck me immediately for two reasons: (1) its immense mathematical beauty, and (2) the unparalleled precision to which its predictions have been verified again and again. Particularly fascinating for me were the predictions of quantum mechanics for individual particles, individual quantum systems. Surprisingly, the experimental realization of many of these fundamental phenomena has led to novel ideas for applications. Starting from my early experiments with neutrons, I later became interested in quantum entanglement, initially focusing on multi-particle entanglement like GHZ states. This work opened the experimental possibility to do quantum teleportation and quantum hyper-dense coding. The latter became the first entanglement-based quantum experiment breaking a classical limitation. One of the most fascinating phenomena is entanglement swapping, the teleportation of an entangled state. This phenomenon is fundamentally interesting because it can entangle two pairs of particles which do not share any common past. Surprisingly, it also became an important ingredient in a number of applications, including quantum repeaters which will connect future quantum computers with each other. Another application is entanglement-based quantum cryptography where I present some recent long-distance experiments. Entanglement swapping has also been applied in very recent so-called loophole-free tests of Bell's theorem. Within the physics community such loophole-free experiments are perceived as providing nearly definitive proof that local realism is untenable. While, out of principle, local realism can never be excluded entirely, the 2015 achievements narrow down the remaining possibilities for local realistic explanations of the quantum phenomenon of entanglement in a significant way. These experiments may go down in the history books of science. Future experiments will address particularly the freedom-of-choice loophole using cosmic sources of randomness. Such experiments confirm that unconditionally secure quantum cryptography is possible, since quantum cryptography based on Bell's theorem can provide unconditional security. The fact that the experiments were loophole-free proves that an eavesdropper cannot avoid detection in an experiment that correctly follows the protocol. I finally discuss some recent experiments with single- and entangled-photon states in higher dimensions. Such experiments realized quantum entanglement between two photons, each with quantum numbers beyond 10 000 and also simultaneous entanglement of two photons where each carries more than 100 dimensions. Thus they offer the possibility of quantum communication with more than one bit or qubit per photon. The paper concludes discussing Einstein's contributions and viewpoints of quantum mechanics. Even if some of his positions are not supported by recent experiments, he has to be given credit for the fact that his analysis of fundamental issues gave rise to developments which led to a new information technology. Finally, I reflect on some of the lessons learned by the fact that nature cannot be local, that objective randomness exists and about the emergence of a classical world. It is suggestive that information plays a fundamental role also in the foundations of quantum physics.
Ulrik L Andersen et al 2016 Phys. Scr. 91 053001
Squeezed light generation has come of age. Significant advances on squeezed light generation have been made over the last 30 years—from the initial, conceptual experiment in 1985 till today's top-tuned, application-oriented setups. Here we review the main experimental platforms for generating quadrature squeezed light that have been investigated in the last 30 years.
S Pfalzner et al 2015 Phys. Scr. 90 068001
The solar system started to form about 4.56 Gyr ago and despite the long intervening time span, there still exist several clues about its formation. The three major sources for this information are meteorites, the present solar system structure and the planet-forming systems around young stars. In this introduction we give an overview of the current understanding of the solar system formation from all these different research fields. This includes the question of the lifetime of the solar protoplanetary disc, the different stages of planet formation, their duration, and their relative importance. We consider whether meteorite evidence and observations of protoplanetary discs point in the same direction. This will tell us whether our solar system had a typical formation history or an exceptional one. There are also many indications that the solar system formed as part of a star cluster. Here we examine the types of cluster the Sun could have formed in, especially whether its stellar density was at any stage high enough to influence the properties of today's solar system. The likelihood of identifying siblings of the Sun is discussed. Finally, the possible dynamical evolution of the solar system since its formation and its future are considered.
Kaj Sotala and Roman V Yampolskiy 2015 Phys. Scr. 90 018001
Many researchers have argued that humanity will create artificial general intelligence (AGI) within the next twenty to one hundred years. It has been suggested that AGI may inflict serious damage to human well-being on a global scale ('catastrophic risk'). After summarizing the arguments for why AGI may pose such a risk, we review the fieldʼs proposed responses to AGI risk. We consider societal proposals, proposals for external constraints on AGI behaviors and proposals for creating AGIs that are safe due to their internal design.
Andrew R Hogan and Andy M Martin 2024 Phys. Scr. 99 055118
Both the Jaynes-Cummings-Hubbard (JCH) and Dicke models can be thought of as idealised models of a quantum battery. In this paper we numerically investigate the charging properties of both of these models. The two models differ in how the two-level systems are contained in cavities. In the Dicke model, the N two-level systems are contained in a single cavity, while in the JCH model the two-level systems each have their own cavity and are able to pass photons between them. In each of these models we consider a scenario where the two-level systems start in the ground state and the coupling parameter between the photon and the two-level systems is quenched. Each of these models display a maximum charging power that scales with the size of the battery N and no super charging was found. Charging power also scales with the square root of the average number of photons per two-level system m for both models. Finally, in the JCH model, the power was found to charge inversely with the photon-cavity coupling κ.
Michael G Raymer and Ian A Walmsley 2020 Phys. Scr. 95 064002
We review the concepts of temporal modes (TMs) in quantum optics, highlighting Roy Glauber's crucial and historic contributions to their development, and their growing importance in quantum information science. TMs are orthogonal sets of wave packets that can be used to represent a multimode light field. They are temporal counterparts to transverse spatial modes of light and play analogous roles—decomposing multimode light into the most natural basis for isolating statistically independent degrees of freedom. We discuss how TMs were developed to describe compactly various processes: superfluorescence, stimulated Raman scattering, spontaneous parametric down conversion, and spontaneous four-wave mixing. TMs can be manipulated, converted, demultiplexed, and detected using nonlinear optical processes such as three-wave mixing and quantum optical memories. As such, they play an increasingly important role in constructing quantum information networks.
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Imane Radja et al 2024 Phys. Scr. 99 065966
Tin sulfide (SnS2) is a material known for its effective photocatalytic activity due to its affordability and wide light spectrum response. To enhance and optimize its optical and chemical characteristics, doping is a straightforward approach that can improve its photocatalytic efficiency. This work focuses on the effect of Cu doping on the structural, optical, and photocatalytic properties of the thin films prepared by the spray-coating approach. XRD confirms the hexagonal SnS2 structure. As the amount of Cu added increases, the crystallite size decreases while dislocation density rises. The XPS findings show that a low concentration of copper (2%) within the SnS2 thin films exhibits both high solubility and exclusively a monovalent state, in contrast to the 4% concentration. The effective band gap is in the range of 1.9–2.2 eV. SEM image reveals a variety of morphologies, and the porosity is reduced with increasing Cu doping. Furthermore, the FTIR study confirms the Sn-S bond present at 753 cm−1. EPR studies reveal the existence of sulfur vacancies in Cu-doped SnS2. Mechanical properties were also affected, with an observed decrease in microhardness as the dopant concentration increased. The photocatalytic activity of the samples is studied by photocatalytic degradation of malachite green and Congo red dyes under visible light irradiation. Additionally, their antibacterial effect against Escherichia coli was examined. This study shows that an optimal amount of Cu doping can significantly increase the photocatalytic performance of SnS2 for efficiently decomposing organic pollutants and enhancing antibacterial activities.
Fatemah H Alkallas et al 2024 Phys. Scr. 99 065972
A highly efficient MnO2-Mn2O3/Poly-2-methylaniline (MnO2-Mn2O3/P2MA) hexagonal nanocomposite is synthesized using a one-pot technique involving oxidation polymerization. The hexagonal morphology and crystalline nature of this nanocomposite, as evidenced by the XRD pattern, affirm its exceptional characteristics. The electrical properties are assessed through charge/discharge behavior and cyclic voltammetry curves, elucidating the storage capabilities of this pseudo supercapacitor using different electrolytes NaOH and HCl. The fabricated supercapacitor exhibits impressive efficiency values of 22 F g−1 in a basic medium and a notably higher 72 F g−1 in an acidic medium at a current density of 0.2 A/g. Similarly, the power density values are calculated at 480 and 478 W.kg−1 for the basic and acidic electrolyte, correspondingly. In the basic medium, the series resistance (RS) and charge transfer resistance (RCT) are 5.2 and 0.7 Ω, respectively. In the acidic medium, these values are notably lower, with RS at 2.82 Ω and RCT at 0.2 Ω. Remarkably, even after 500 cycles, the supercapacitor stability remains high at 95% in both media, underscoring the enduring stability attributed to the oxides and polymer materials within the supercapacitor. The combination of cost-effectiveness, ease of fabrication, and potential for mass production positions this supercapacitor as a promising candidate for industrial applications of polymer-based supercapacitors.
Martin Beneke et al 2024 Phys. Scr. 99 065240
The inverted pendulum is a mechanical system with a rapidly oscillating pivot point. Using techniques similar in spirit to the methodology of effective field theories, we derive an effective Lagrangian that allows for the systematic computation of corrections to the so-called Kapitza equation. The derivation of the effective potential of the system requires non-trivial matching conditions, which need to be determined order by order in the power-counting of the problem. The convergence behavior of the series is investigated on the basis of high-order results obtained by this method. The results from this analysis can be used to determine the regions of parameter space, in which the inverted position of the pendulum is stable or unstable to high precision.
Sanam Saleem et al 2024 Phys. Scr. 99 065965
In the present study, the ferromagnetic semiconductor behavior of Mn doped BaTe is reported along with their physical properties. The calculations are done by full potential linearized augmented plane wave (FP-LAPW) approach within spin-polarized density functional theory (SP-DFT). Formation energies were computed to satisfy the stability of reported alloys. The spin-polarization is included in the calculations to study the electronic (band structure (BS), density of states (DOS)) and magnetic characteristics. Ba1−xMnxTe elucidates the magnetic semiconductor nature with direct band gap (Eg) in both spin channels while indirect Eg (1.66 eV) is observed for pure BaTe compound. Stable ferromagnetic (FM) states are vindicated owing to the p-d hybridization which are contributors in inducing magnetic moments (μB) at interstitial and non-magnetic sites. The optical parameters (reflectivity, absorption coefficient, refraction, optical conductivity and dielectric function) were computed within an energy range of 0–10 eV. Thermoelectric (TE) features are also figured using Boltaz-Trap code in terms of thermal and electrical conductivity, figure of merit, Seebeck coefficient and power factor. The analysis of optical parameters suggests that the considered alloys is active within visible to UV-range, having potential applications in optoelectronic, photovoltaic and thermoelectric applications.
Yue Zhao et al 2024 Phys. Scr. 99 065540
hBN is a natural hyperbolic van der Waals material that can enhance light–matter interactions. In this work, the maximum Goos-Hanchen(GH) shift has a magnitude of −4680 μm with high reflection using the central beam method in the trapezoidal dielectric/hBN grating (TDG) metasurface (MS) where the beam waist Analysis of the electromagnetic field distribution indicated that the amplified GH shift was a result of guided mode resonances excited in the waveguide dielectric layer. The frequency and magnitude of GH shifts can be effectively controlled by adjusting the height of the trapezoidal hBN, as well as by manipulating the widths of the top and bottom dielectric layers, the period of the TDG structure, and the height of the multi-layered structure. Moreover, an evaluation of the structure-sensing properties based on the GH shift was conducted. The enhanced and controllable GH shift exhibited by the TDG MS presents promising prospects for applications in optical sensors, optical switches, and optoelectronic detectors.
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Amrinder Mehta et al 2024 Phys. Scr. 99 062006
Shape Memory Alloys (SMAs) are metallic materials with unique thermomechanical characteristics that can regain their original shape after deformation. SMAs have been used in a range of industries. These include consumer electronics, touch devices, automobile parts, aircraft parts, and biomedical equipment. In this work, we define the current state of the art in SMA manufacturing and distribution across the aerospace, healthcare, and aerospace industries. We examine the effect of manganese on the structure and mechanical and corrosive properties of SMA Cu-Al-Ni and discuss the importance of incorporating small and medium-sized enterprises in the study of cu-Al luminum. This research outlines a fundamental example of SME integration in the analysis of superelasticity, a critical instance of SMA activity. It can also serve as a reference for activities such as medical, aerospace, and other industries that target SMA-based equipment and systems. Also, they can be used to look at SMA activation and material upgrade mechanisms. These FEM simulations are advantageous in optimizing and promoting design in fields such as aerospace and healthcare. FEM simulations identify the stress and strength of SMA-based devices and structures. This would result in minimizing cost and usage and lowering the risk of damage. FEM simulations can also recognize the weaknesses of the SMA designs and suggest improvements or adjustments to SMA-based designs.
Kishore Kumar Venkatesan and Sathiyan Samikannu 2024 Phys. Scr. 99 062005
The incredible characteristics of nanomaterial and the benefits of optical fiber may be coupled to provide an exciting new platform for sensing applications. In recent years, there has been significant development and documentation of numerous gas and humidity sensors utilizing optical fiber based on 2D nanomaterials. This review primarily examines the most recent implementations in fiber optic gas and humidity sensing through 2D nanomaterials. With the help of nanomaterial, researchers may be able to fine-tune sensor parameters like thickness, roughness, specific area, refractive index, etc. This could make it possible for sensors to respond faster or to be more sensitive than standard sensors. Optical sensors are a family of devices that use different types of light interactions (i.e., photon-atom) to sense, analyze, and measure molecules for various purposes. Optical sensors are capable of detecting light, often within a narrow band of the electromagnetic spectrum (ultraviolet, visible, and infrared). A fiber optic sensor is an optical device that transforms the physical state of the object being measured into a quantifiable optical signal. Based on the photoelectric effect, the sensor detects light's wavelength, frequency, or polarisation and transforms it into an electric signal. This review describes the state-of-the-art research in this rapidly evolving sector, impacting sensor type, structure, synthesis, deposition process, detection range, sensitivity, response & recovery time, and application of 2D materials. Lastly, the problems that are currently in the way of using 2D materials in sensor applications are talked about, as well as what the future might hold.
Chithiika Ruby V and Lakshmanan M 2024 Phys. Scr. 99 062004
Liénard-type nonlinear oscillators with linear and nonlinear damping terms exhibit diverse dynamical behavior in both the classical and quantum regimes. In this paper, we consider examples of various one-dimensional Liénard type-I and type-II oscillators. The associated Euler–Lagrange equations are divided into groups based on the characteristics of the damping and forcing terms. The Liénard type-I oscillators often display localized solutions, isochronous and non-isochronous oscillations and are also precisely solvable in quantum mechanics in general, where the ordering parameters play an important role. These include Mathews-Lakshmanan and Higgs oscillators. However, the classical solutions of some of the nonlinear oscillators are expressed in terms of elliptic functions and have been found to be quasi-exactly solvable in the quantum region. The three-dimensional generalizations of these classical systems add more degrees of freedom, which show complex dynamics. Their quantum equivalents are also explored in this article. The isotonic generalizations of the non-isochronous nonlinear oscillators have also been solved both classically and quantum mechanically to advance the studies. The modified Emden equation categorized as Liénard type-II exhibits isochronous oscillations at the classical level. This property makes it a valuable tool for studying the underlying nonlinear dynamics. The study on the quantum counterpart of the system provides a deeper understanding of the behavior in the quantum realm as a typical -symmetric system.
Dennis Bonatsos et al 2024 Phys. Scr. 99 062003
Prolate to oblate shape transitions have been predicted in an analytic way in the framework of the Interacting Boson Model (IBM), determining O(6) as the symmetry at the critical point. Parameter-independent predictions for prolate to oblate transitions in various regions on the nuclear chart have been made in the framework of the proxy-SU(3) and pseudo-SU(3) symmetries, corroborated by recent non-relativistic and relativistic mean field calculations along series of nuclear isotopes, with parameters fixed throughout, as well as by shell model calculations taking advantage of the quasi-SU(3) symmetry. Experimental evidence for regions of prolate to oblate shape transitions is in agreement with regions in which nuclei bearing the O(6) dynamical symmetry of the IBM have been identified, lying below major shell closures. In addition, gradual oblate to prolate transitions are seen when crossing major nuclear shell closures, in analogy to experimental observations in alkali clusters.
Raghavendra Garlapally et al 2024 Phys. Scr. 99 062002
The present summarized study focused on Anodically fabricated TiO2 nanotubes array shows an exceptional physical and chemical properties due to their high surface area as well as thickness near to nano scale regimes. Crystallization of an amorphous TiO2 nanotube plays an important role when it comes to applications point of view. Studies revealed that a change in the annealing process resulted in an enhancement in their structure and properties. In this review, we mainly focus on various annealing techniques, their advantages and drawbacks over the other methods. Additionally, we have reported the effect of morphology and crystal structure of different annealed anodically grown TiO2 nanotubes. Therefore, the anodized TiO2 nanotubes array review will not only have applications in water splitting, hydrogen generation, solar cells but also a suitable potential candidate in the immense applications as micro/nano needles for drug delivery in biomedical as well as different electronic device/sensing approaches in aerospace sectors as well.
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Svechnikova et al
In this work, we studied the effects of three cryoprotectors – ethylene glycol, dimethyl sulfoxide and sucrose – on the compression isotherms of egg yolk Langmuir monolayers both in the presence and in the absence of cholesterol in the monolayer. The influence of calcium ions from the subphase affecting the effectiveness of cryoprotection on isotherms is also examined. In addition, the elastic properties of the obtained monolayers are investigated by calculation and comparison the compression modulus of the monolayer. The scientific novelty of the work is in consideration of a complex biosimilar system (an egg yolk monolayer, cholesterol and their mixtures) on the surface of the aqueous solution of the nutrient mixture and obtaining information about the specific interaction of different cryoprotectors with lipid membranes. We found that when calcium ions and cryoprotectors are simultaneously added to the subphase, they block each other's influence on the lipid monolayer and reduce the effectiveness of cryoprotection. Cholesterol in the yolk in a ratio of 1:50 m/m changes the properties of the monolayer, which leads to increased action of cryoprotectors. Also, for the first time, the effect of a significant increase in surface pressure (by ~20 mN/m) was detected when cryoprotectors were added to the system under consideration. This effect can serve as an indicator of the effectiveness of membrane dehydration by cryoprotectors and be used to find the most effective and safe cryoprotector compositions. The obtained data can provide important recommendations for the development of cryoprotective media for cell freezing. Since the study of the mechanisms of calcium interaction (the most important signaling cation) with biological membrane and membrane-like systems is important for understanding the various effects caused by medicinal and biologically active drugs at the cellular level, the study is of interest for various fields of biophysics and biomedicine.
hussain et al
Multiferroics with strong magnetoelectric coupling can be created by improving the magnetostriction of the ferrite phase and combining it with the best known piezoelectric. Herein, the ferromagnetic CoFe2O4 was modified with Al3+ ions (CAF) to further improve the resistivity, magnetic, and magnetostrictive properties and then combined with (0.5)Ba(Zr0.2Ti0.8)O3−(0.5)(Ba0.7Ca0.3)TiO3(BCZT) with different weight percentages. XRD results revealed the presence of a mixed spinel cubic phase for CAF (Fd-3m), whereas BCZT crystallized in a tetragonal structure (Amm2) in composite systems. Composites exhibited well-developed hysteresis loops with no feature of leakage current and dielectric response was consistent with ferroelectric properties. The magnetic response of CAF sample improved significantly which is attributed to preference of Al3+ ions on tetrahedral sites. The magnetization of composites increased as the nonmagnetic BCZT component increased and (0.75)CAF-(0.25)BCZT system had the highest saturation magnetization. We anticipate that these systems will have significantly improved magnetoelectric characteristics than unmodified CF-BCZT system.
Eid et al
The mechanical characteristics of Sn-1.5Ag-0.5Cu (SAC155) alloy modified with In, Bi, and Te microalloying are investigated in relation to three strengthening mechanisms that withstand coarsening: i) micron-scale Ag3Sn, Cu6Sn5, SnTe, Ag2In and InSn4 IMC precipitated phases, ii) Bi in solid solution and iii) Bi precipitated particles formed upon eutectic solidification. Compared to SAC155 alloy with a single strengthening mechanism, the combined effect of threedeformation processes operating in SAC(155)-3Bi-2In with high In content and SAC(155)-3Bi-0.2Te (wt%) with low Te content alloys greatly improved the mechanical properties at high temperatures. It was found that, despite a discernible reduction in ductility, the high In content could refine the microstructure,enrich the elastic modulus (E), yield stress (YS), and ultimate tensile strength (UTS) of SAC(155)-3Bi-2In to almost 2.3 times that of SAC155 solder. On the other hand, a low Te content greatly increased SAC(155)-3Bi-0.2Te's mechanical strength ⁓2.3 times, while a large atomic size difference between Te and Sn atoms caused excessive misfit strain, which in turn increased Bi's solubility in β-Sn grains, and improved ductility by approximately twice that of SAC(155)-3Bi-2In solder.
Riaz et al
In this study, an examination of the Yu-Toda-Sasa-Fukuyama equation is undertaken, a model that characterizes elastic waves in a lattice or interfacial waves in a two layer liquid. Our emphasis lies in conducting a comprehensive analysis of this equation through various viewpoints, including the examination of soliton dynamics, exploration of bifurcation patterns, investigation of chaotic phenomena, and a thorough evaluation of the model's sensitivity. Utilizing a simplified version of Hirota's approach, multi-soliton pattens, including 1-wave, 2-wave, and 3-wave solitons, are successfully derived. The identified solutions are depicted visually via 3D, 2D, and contour plots using Mathematica software. The dynamic behavior of the discussed equation is explored through the theory of bifurcation and chaos, with phase diagrams of bifurcation observed at the fixed points of a planar system. Introducing a perturbed force to the dynamical system, periodic, quasi-periodic and chaotic patterns are identified using the RK4 method. The chaotic nature of perturbed system is discussed through Lyapunov exponent analysis. Sensitivity and multistability analysis are conducted, considering various initial conditions. The results acquired emphasize the efficacy of the methodologies used in evaluating solitons and phase plots across a broader spectrum of nonlinear models.
Bai et al
The bond-dependent Kitaev interaction K is familiar in the effective spin model of transition
metal compounds with octahedral ligands. In this work, we find a peculiar non-coplanar magnetic
order can be formed with the help of K and next-nearest neighbor Heisenberg coupling J2 on the
triangular lattice. It can be seen as a miniature version of skyrmion crystal, since it has nine spins
and an integer topological number in a magnetic unit cell. The magnon excitations in such an order
are studied by the linear spin-wave theory. Of note is that the change in the relative size of J2 and K
produces topological magnon phase transitions although the topological number remains unchanged.
We also calculated the experimentally observable thermal Hall conductivity, and found that the signs
of thermal Hall conductivity will change with topological phase transitions or temperature changes in
certain regions.
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Martin Beneke et al 2024 Phys. Scr. 99 065240
The inverted pendulum is a mechanical system with a rapidly oscillating pivot point. Using techniques similar in spirit to the methodology of effective field theories, we derive an effective Lagrangian that allows for the systematic computation of corrections to the so-called Kapitza equation. The derivation of the effective potential of the system requires non-trivial matching conditions, which need to be determined order by order in the power-counting of the problem. The convergence behavior of the series is investigated on the basis of high-order results obtained by this method. The results from this analysis can be used to determine the regions of parameter space, in which the inverted position of the pendulum is stable or unstable to high precision.
Shubin Yan et al 2024 Phys. Scr. 99 065541
In this study, a nanoscale refractive index sensor structure is proposed, which is realised using a metal-insulator-metal (MIM) waveguide and a grooved circular ring with double disk cavity (GRDD) structure coupled to each other. The finite element method (FEM) was used to analyze and investigate the effects of the variations of each structural parameter on the transmittance spectra and the comprehensive performance of the sensor. Based on the simulation results, the optimum sensitivity parameter of the sensor structure is 2800 nm R−1IU−1 with a figure of merit (FOM) value of 51.9 RIU−1. The sensor structure is capable of being used in biomedical field with sensitivities of and respectively, for detecting hemoglobin of blood types A, B, and O, and for detecting glucose concentration.
Ibrahim Elbatal et al 2024 Phys. Scr. 99 065231
In this research, we investigate a brand-new two-parameter distribution as a modification of the power Zeghdoudi distribution (PZD). Using the inverse transformation technique on the PZD, the produced distribution is called the inverted PZD (IPZD). Its usefulness in producing symmetric and asymmetric probability density functions makes it the perfect choice for lifetime phenomenon modeling. It is also appropriate for a range of real data since the relevant hazard rate function has one of the following shapes: increasing, decreasing, reverse j-shape or upside-down shape. Mode, quantiles, moments, geometric mean, inverse moments, incomplete moments, distribution of order statistics, Lorenz, Bonferroni, and Zenga curves are a few of the significant characteristics and aspects explored in our study along with some graphical representations. Twelve effective estimating techniques are used to determine the distribution parameters of the IPZD. These include the Kolmogorov, least squares (LS), a maximum product of spacing, Anderson-Darling (AD), maximum likelihood, minimum absolute spacing distance, right-tail AD, minimum absolute spacing-log distance, weighted LS, left-tailed AD, Cramér-von Mises, AD left-tail second-order. A Monte Carlo simulation is used to examine the effectiveness of the obtained estimates. The visual representation and numerical results show that the maximum likelihood estimation strategy regularly beats the other methods in terms of accuracy when estimating the relevant parameters. The usefulness of the recommended distribution for modelling data is illustrated and displayed visually using two real data sets through comparisons with other distributions.
L Bolzoni and F Yang 2024 Phys. Scr. 99 065024
X-ray diffraction (XRD) is routinely used to characterise Ti alloys, as it provides insight on structure-related aspects. However, there are no dedicated reports on its accuracy are available. To fill this gap, this work aims at examining the benefits and limitations of XRD analysis for phase identification in Ti-based alloys. It is worth mentioning that this study analyses both standard and experimental Ti alloys but the scope is primarily on alloys slow cooled from high temperature, thus characterised by equilibrium microstructures. To be comprehensive, this study considers the all spectrum of Ti alloys, ranging from alpha to beta Ti alloys. It is found that successful identification and quantification of the phases is achieved in the majority of the different type of Ti-based alloys. However, in some instances like for near-alpha alloys, the output of XRD analysis needs to be complemented with other characterisation techniques such as microscopy to be able to fully characterise the material. The correlation between the results of XRD analysis and the molybdenum equivalent parameter (MoE), which is widely used to design Ti alloys, was also investigated using structural-analytical models. The parallel model is found to be the best to estimate the amount of β-Ti phase as a function of the MoE parameter.
Davide Stirpe et al 2024 Phys. Scr.
We study here the semiclassical dynamics of a superconducting circuit constituted by two Josephson junctions in series, in the presence of a voltage bias. We derive the equations of motion for the circuit through a Hamiltonian description of the problem, considering the voltage sources as semi-holonomic constraints. We find that the dynamics of the system corresponds to that of a planar rotor with an oscillating pivot. We show that the system exhibits a rich dynamical behaviour with chaotic properties and we present a topological classification of the cyclic solutions, providing insight into the fractal nature of the dynamical attractors.
Vu Thanh Tung et al 2024 Phys. Scr.
A time-of-flight–based ranging system constructed by an intensity-modulated light source and photodetectors (PDs) is proposed. In the proposed system, the carrier wave, which comprises two cosine waves with different frequencies in the megahertz range, is reconstructed from a few samples obtained by PDs with a kilohertz sampling rate using the compressive sensing technique. This allows the system to observe the distance with very high accuracy and it also extends the measurement range while maintaining the accuracy of an existing system that utilizes a single-frequency carrier.
Bryan J Dalton 2024 Phys. Scr.
In this paper we consider the description by a general Bell-type non-local hidden variable theory of bipartite quantum states with two observables per sub-system. We derive Bell inequalities of the Collins-Gisin.-Liden-Massar-Popescu type which involve combinations of the probabilities of related outcomes for measurements for the four pairs of sub-system observables. It is shown that the corresponding quantum theory expressions violate the Bell inequalities in the case of the maximally entangled state of the bipartitite system. The CHSH Bell inequality is also derived from this general CGLMP Bell-type non-local hidden variable theory. This shows that quantum theory can not be underpinned by a Bell-type non-local hidden variable theory. So as a general Bell-type local hidden variable theory has already been shown to conflict with quantum theory, it follows that quantum theory can not be understood in terms of any CGLMP Bell-type hidden variable theory - local or non-local.
P Sarkar et al 2024 Phys. Scr. 99 065952
In thin film multilayer based optical componentsof x-ray imaging system, diffusion of one material into the other degrades the reflectivity of the mirrors severely. Along with this thermodynamically driven diffusion, there are also growth generated interface roughness of different special frequencies and microstructures which can increase the diffused scattering from the multilayer and reduce the resolution of an image. Generally grazing incidence x-ray reflectivity in specular geometry (specular GIXR) and diffused x-ray scattering measurement in rocking scan geometry yield information regarding microstructure and overall diffusion at the interfaces of a multilayer. In this paper it is shown that grazing incidence x-ray fluorescence (GIXRF) measurement in standing wave condition alongwith the above measurements can give precise information regarding element-specific diffusion at the interfaces of a multilayer structure. Periodic multilayers made of 75 Cr/Sc bilayers with bilayer thickness ∼4 nm with and without B4C barrier layer of 0.2 nm thickness at the interfaces have been prepared using ion beam sputtering system and characterized by GIXR, diffused x-ray scattering and GIXRF measurements using synchrotron x-ray radiation just above the Cr K-edge. From the above measurements, drastic reduction in interface diffusion of Cr and improvement of interface morphology after addition of B4C barrier layer at the interfaces of Cr/Sc multilayers have been observed which is also corroborated by cross-sectional transmission electron microscopy of the multilayers. Finally, in the water window soft x-ray region of 2.3–4.4 nm performance of these multilayers have been tested and the Cr/B4C/Sc multilayer with improved interface quality has been found to yield ∼30.8% reflectivity at 3.11 nm wavelength which is comparable with the best reported reflectivities in the literature at this wavelength.
Man Li et al 2024 Phys. Scr. 99 065531
To obtain a highly linearly polarized light, a composite model consisting of white light emission, anti-reflection film, and metal-dielectric-metal nanowire grating was designed, analyzed, optimized, and fabricated. Based on the finite-difference time-domain method, the impacts of material, period, height, and incidence angle on the polarization performance of the composite model were discussed. The metal-dielectric-metal nanowire grating was fabricated on blue chip and fluorescent ceramics using nanoimprint technology. The employed materials of metal-dielectric-metal nanowire grating were aluminum and PMMA, with the period of 200 nm, wire width of 100 nm, and the height of metal and dielectric were 100 nm and 120 nm. Additionally, the anti-reflection film consisting of PMMA with the thickness of 45 nm was incorporated on fluorescent ceramics to enhance energy efficiency. Finally, through a series of test experiments, the composite model can be realized by the extinction ratio of 40 dB, while the transmittance of TM mode exceeds 50% at 450–750 nm. The theoretical analysis of this study is verified by experiments, and it has significant potential in the pursuit of high brightness, ultra-thin micro displays.
Mengqian Ding et al 2024 Phys. Scr.
Recently, image analysis techniques have been introduced to automate nematode information assessment. In image analysis-based nematode information assessment, the initial step involves detecting and segmenting C. elegans from microscopic images and network-based methods have been investigated. However, training a network for C. elegans image segmentation is typically associated with the labor-intensive process of pixel-level mask labeling. To address this challenge, we introduced a weakly supervised segmentation method using multiple instance learning (WSM-MIL). The proposed multi-instance weakly supervised segmentation method comprises three key components: a backbone network, a detection branch, and a segmentation branch. In contrast to fully supervised pixel-level annotation, we opted for weakly supervised bounding box-level annotation. This approach reduces the labour cost of annotation to some extent. The approach offers several advantages, such as simplicity, an end-to-end architecture, and good scalability. We conducted experiments comparing the proposed network with benchmark methods, and the results showed that the network exhibits competitive performance in the image segmentation task of C. elegans. The results of this study provide an effective method in the field of biological image analysis, as well as new ideas for solving complex segmentation tasks. The method is not only applicable to the study of C. elegans but also has wide applicability in biological image segmentation problems in other fields.