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.
As a society-owned publisher with a legacy of serving scientific communities, we are committed to offering a home to all scientifically valid and rigorously reviewed research. In doing so, we aim to accelerate the dissemination of scientific knowledge and the advancement of scholarly communications to benefit all.
Physica Scripta supports this mission and actively demonstrates our core values of inclusive publishing and trusted science. To find out more about these values and how they can help you publish your next paper with us, visit our journal scope.
Purpose-led Publishing is a coalition of three not-for-profit publishers in the field of physical sciences: AIP Publishing, the American Physical Society and IOP Publishing.
Together, as publishers that will always put purpose above profit, we have defined a set of industry standards that underpin high-quality, ethical scholarly communications.
We are proudly declaring that science is our only shareholder.
ISSN: 1402-4896
Physica Scripta is a broad scope, international journal dedicated to presenting high quality research covering all areas of physics and related multidisciplinary topics across the physical sciences.
Why choose this journal?- Trustworthy science backed by rigorous peer review
- Inclusive publishing practices focused on scientific validity
- Find out more about our scope
Open all abstracts, in this tab
Jack Smith 2022 Phys. Scr. 97 122001
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.
Gerard 't Hooft et al 2024 Phys. Scr. 99 052501
Despite its amazing quantitative successes and contributions to revolutionary technologies, physics currently faces many unsolved mysteries ranging from the meaning of quantum mechanics to the nature of the dark energy that will determine the future of the Universe. It is clearly prohibitive for the general reader, and even the best informed physicists, to follow the vast number of technical papers published in the thousands of specialized journals. For this reason, we have asked the leading experts across many of the most important areas of physics to summarise their global assessment of some of the most important issues. In lieu of an extremely long abstract summarising the contents, we invite the reader to look at the section headings and their authors, and then to indulge in a feast of stimulating topics spanning the current frontiers of fundamental physics from 'The Future of Physics' by William D Phillips and 'What characterises topological effects in physics?' by Gerard 't Hooft through the contributions of the widest imaginable range of world leaders in their respective areas. This paper is presented as a preface to exciting developments by senior and young scientists in the years that lie ahead, and a complement to the less authoritative popular accounts by journalists.
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.
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.
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.
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.
Jawad Mirza et al 2024 Phys. Scr. 99 055513
The spectrum required for future optical communication systems is being extended towards the C-, L- and U-bands, resulting in a significant interest in the spectral region around 2 μm wavelength. Since Holmium doped fiber amplifiers (HDFAs) provide amplification in this spectral region, they have become a focus of researchers working on doped fiber amplifiers. A major factor resulting in the performance degradation of HDFAs is the inhomogeneous energy transfer within Ho3+ ion-pairs in high-concentration Holmium-doped fibers (HDFs), an effect generally known as pair-induced quenching (PIQ). In this paper, we study the luminal and temporal dynamics of pulses of different repetition rates at 2.05 μm in high-concentration HDFs considering the effects of ion-pairs. Input pulses having repetition rates of 25 GHz and 500 kHz are generated using wavelength tunable actively mode-locked Holmium-doped fiber laser (AML-HDFL) based on a single ring cavity and bidirectional pumping. The characteristics of the pulses propagating through high-concentration HDF are analyzed based on different metrics such as average power, peak power, pulse energy, full-width at half maximum (FWHM), and time delay without and with ion-pairs for values of fraction of ion-pairs k = 0 and k = 10%, respectively. The results obtained at optimized length of HDF show that ion-pairs significantly degrade the average power, peak power, and energy of the output pulses for both of the repetition rates. For both k = 0 and k = 10%, the FWHM and shape of the output pulses remain same in the presence of the ion-pairs while, time delay of 4 ps and 19 ns is observed in the output pulses at repetition rates of 25 GHz and 500 kHz, respectively. The effects of increasing the pump and signal power on the average power and energy of the output pulses for k = 0 and k = 10% are also discussed for both repetition rates. This analysis provides important guidelines for designers of 2 μm fiber lasers and amplifiers based on high-concentration HDFs.
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?
Open all abstracts, in this tab
Xiuhua Yang et al 2024 Phys. Scr. 99 075909
A reclining mold can support the soft forming of fused silica substrates into micro-hemispherical shells with the same height, which makes the processing of micro-hemispherical shells attractive. Currently, it is difficult to determine the optimal process parameters for machining micro-hemispherical shells, and several iterations of experiments are required. This process wastes large amounts of substrate material, experimental consumables, and machining time, and increases the cost of the experiments. In this paper, we report a reflow process for soft-forming micro-hemispherical shells from fused silica substrates supported by a reclining mold. The shapes of the shells formed from the fused silica substrates in reclining and non-reclining molds were analysed by building a two-dimensional model. Moreover, we predicted the effects of varying the process parameters on the shell-forming time and geometrical parameters, as well as the stresses and deformations of the shells after cooling. The effect of the eccentricity of the central support column of the mold on the symmetry of micro-hemispherical shells was also investigated, and the influence of the mold and substrate heating inhomogeneity on micro-hemispherical shell formation was analysed. Additionally, the heat uniformity of the substrate in the rotating state was examined. Finally, we investigated the temperature field and thickness distribution during the shell-forming process through 3D modelling to verify the 2D modelling results. Analysing and predicting the parameters helps to reduce the number of trial-and-error processes in experiments, and we expect this work to provide a theoretical parametric basis for micro-hemispherical shell machining.
Abdul Haseeb Hassan Khan et al 2024 Phys. Scr. 99 075505
In recent years, Perovskite solar cells (PSC) have showed promising results to substitute traditional PV technologies due to impressive power conversion efficiency (PCE) and cost-effective production. This study investigates the impact of introducing a Cs4CuSb2Cl12 (CCSC) perovskite quantum dot (PQD) interface layer among active layer and hole transport layer (HTL) in CsGeI3 as well as MAGeI3-based PSCs. It aims in enhancing the function of interface layer (IL) by improving PCE while reducing interface losses. TiO2 and Spiro-OMeTAD were employed as the electron transport layer (ETL) and HTL, respectively. SCAPS-1D software was utilized for simulating JSC, VOC, FF, and PCE of various configurations, including passivated and non-passivated structures. The results revealed a substantial increase in JSC from 13.22 mA cm−2 to 15.5 mA cm−2 and PCE from 11.67% to 14.81% for MAGeI3-based PSCs with incorporated PQD layer. Additionally, the fill factor (FF) improved from 50.55% to 76.90%. However, a decrease in VOC from 1.7 V towards 1.24 V was noticed, this was associated with the formation of an energy barrier at HTL/ absorber. For CsGeI3-based devices, a slight improvement in JSC was observed from 21.0 mA cm−2 to 21.8 mA cm−2, whereas VOC remained constant at 1.24 V. The PCE increased from 22.50% to 23.09%, but the FF decreased from 86.83% to 85.48%. However the decrease in the fill factor (FF) may be attributable to a rise in the cell series resistance due to the additional interface, which could impede charge transport and extraction. This simulation study demonstrates that the incorporation of a CCSC PQD IL among active layer / HTL can enhance the PCE and short circuit current of CsGeI3 and MAGeI3-based PSCs, providing a promising avenue for future optimizations and advancements in PSC technologies.
Li Bai et al 2024 Phys. Scr. 99 076002
In this study, an assessment of concrete compressive strength was conducted using an impulse excitation data-driven machine learning (ML) framework. The model was constructed upon a deep neural network and aided by the backpropagation method, ensuring a precise training process. In contrast to prior research, which mainly focused on mixture components, a meaningful relationship between physical parameters—resonant frequencies and elastic moduli—and compressive strength was established by our ML model. Remarkable performance was demonstrated, with a root mean square error value of 2.8MPa and a determination factor of 0.97. Through Pearson analysis, correlations between input features and output targets, ranging from −0.29 to 0.90, were revealed. Notably, the strongest correlations with compressive strength were found in Young's and shear moduli, derived from flexural and torsional frequencies, highlighting the pivotal role of dynamic elastic response in concrete's mechanical behavior. Furthermore, the findings indicated slight prediction deviations in cases involving samples with a high Poisson's ratio. This work illuminates the potential for accurate compressive strength prediction by leveraging concrete's dynamic response, particularly flexural and torsional modes, thereby opening avenues for research into concrete compressive strength without direct consideration of sample ingredients.
Bikash Modak and Muthu P 2024 Phys. Scr. 99 075006
Motivation. The immune response to the viral transmission experiences delays due to diverse biological factors and is affected by several factors. These include infection rate, rate of apoptosis and impact of the antibody-virus complex which exhibit unpredictable nature in a random environment. Objective. The main goal is to examine the impact of noise terms, introduced into every state variable, on a delayed in-host model of viral transmission. Methodology. To determine the intensity fluctuations and variances of all concerned state variables in the stochastic delayed model, which includes a constant delay and Gaussian white noise, the Fourier transformation method is employed. Results and Conclusions. The limiting value of the delay parameter is derived explicitly as well as numerically. The system experiences Hopf bifurcation, whenever the delay parameter crosses the limiting value which is shown graphically. The intensities and variances of different cells and virus populations are derived and the values are computed numerically. As the delay increases, the level of viremia decreases while other parameters maintain fixed values. The outcomes of data sensitivity, shown in graphical form, indicate that the transmission rate and supply rate of viruses are highly sensitive. Our findings suggest that the presence of noise causes fluctuations in the delayed model, leading to a noticeable impact on the transmission of the virus.
Himadri Nirjhar Mandal and Soumya Sidhishwari 2024 Phys. Scr. 99 075504
An apodized fiber Bragg grating (FBG) is introduced with a proposed apodization function for the effective quasi-distributed sensing estimation of the temperature and the strain. FBG features such as reflectivity, side lobes, and bandwidth have been optimized for the designed apodized grating to upgrade the effectiveness of FBG for properly measuring the variations in the Bragg wavelength. Based upon the simulation, a comparative analytical study on FBG properties with different apodization function profiles has been demonstrated to achieve the optimum profile with high reflectivity, narrow bandwidth and minimal range of side lobes for quasi-distributed sensing estimation of parameters. A strong linearity has been noted for the sensitivity of designed FBG with different apodization profiles for the temperature and the strain estimation subsequently. It has been reported that the obtained sensitivity of measurands for the FBG with proposed apodization profile are higher as compared with the other profiles. The wavelength division multiplexing (WDM) based quasi-distributed network of four optimized FBGs have been implemented for different apodization profiles to illustrate the impact of apodization to prevent overlapping between neighbouring FBG spectrums in the sensing network with spatial resolution of 2 nm. The maximal detectable temperature/strain sensitivity estimation of 153 °C/1439 μ have been obtained for the proposed apodized FBG along with minimal detectable temperature/strain ranges of −102 °C/−1345 μ in the quasi-distributed network. The achieved ranges with optimum resolution can be implemented effectively in quasi-distributed based sensing application for condition observation of civil infrastructures in any complex circumstances.
Open all abstracts, in this tab
Da Zhang et al 2024 Phys. Scr. 99 062010
The arc discharge plasma (ADP) technology has been widely developed in the fields of cutting, welding, spraying and nanomaterials synthesis over the past 20 years. However, during the process of ADP, it is difficult to explain the generation and evolution of arc column, the interaction between arc column and electrodes, as well as the effect of plasma generator structure on the physical characteristics of ADP by experimental means. Therefore, numerical simulation has become an effective mean to explore the physical characteristics of ADP, but also faces severe challenges because it involves multiple physical field coupling, resolution of multiscale features as well as robustness in the presence of large gradients. From the point of view of the construction of ADP mathematical physical models and combined with the practical application of ADP, this paper systematically reviews the researches on physical properties of arc column, near-cathode region, near-anode region as well as the today's state of the numerical simulation of plasma generators. It provides a good reference for further mastering the physical characteristics of plasma, guiding the industrial application of plasma and optimizing the design of plasma generators. Meanwhile, the relevant computational aspects are discussed and the challenges of plasma numerical simulation in the future are summarized.
Muhammad Usman et al 2024 Phys. Scr. 99 062009
Infectious diseases caused by bacterial pathogens are currently a significant problem for global public health. Rapid diagnosis and effective treatment of clinically significant bacterial pathogens can prevent, control, and inhibit infectious diseases. Therefore, there is an urgent need to develop selective and accurate diagnostic methods for bacterial pathogens and clinically effective treatment strategies for infectious diseases. In recent years, developing novel nanoparticles has dramatically facilitated the rapid and accurate diagnosis of bacterial pathogens and the precise treatment of contagious diseases. In this review, we systematically investigated a variety of nanoparticles currently applied in the diagnosis and treatment of bacterial pathogens, from synthesis procedures to structural characterization and then to biological functions. In particular, we first discussed the current progress in applying representative nanoparticles for bacterial pathogen diagnostics. The potential nanoparticle-based treatment for the control of bacterial infections was then carefully explored. We also discussed nanoparticles as a drug delivery method for reducing antibiotic global adverse effects and eradicating bacterial biofilm formation. Furthermore, we studied the highly effective nanoparticles for therapeutic applications in terms of safety issues. Finally, a concise and insightful discussion of nanoparticles' limitations, challenges, and perspectives for diagnosing and eradicating bacterial pathogens in clinical settings was conducted to provide a direction for future development.
M E Semenov et al 2024 Phys. Scr. 99 062008
The Preisach model is a well-known model of hysteresis in the modern nonlinear science. This paper provides an overview of works that are focusing on the study of dynamical systems from various areas (physics, economics, biology), where the Preisach model plays a key role in the formalization of hysteresis dependencies. Here we describe the input-output relations of the classical Preisach operator, its basic properties, methods of constructing the output using the demagnetization function formalism, a generalization of the classical Preisach operator for the case of vector input-output relations. Various generalizations of the model are described here in relation to systems containing ferromagnetic and ferroelectric materials. The main attention we pay to experimental works, where the Preisach model has been used for analytic description of the experimentally observed results. Also, we describe a wide range of the technical applications of the Preisach model in such fields as energy storage devices, systems under piezoelectric effect, models of systems with long-term memory. The properties of the Preisach operator in terms of reaction to stochastic external impacts are described and a generalization of the model for the case of the stochastic threshold numbers of its elementary components is given.
A Srinivasa Rao 2024 Phys. Scr. 99 062007
Over the past 36 years much research has been carried out on Bessel beams (BBs) owing to their peculiar properties, viz non-diffraction behavior, self-healing nature, possession of well-defined orbital angular momentum with helical wave-front, and realization of smallest central lobe. Here, we provide a detailed review on BBs from their inception to recent developments. We outline the fundamental concepts involved in the origin of the BB. The theoretical foundation of these beams was described and then their experimental realization through different techniques was explored. We provide an elaborate discussion on the different kinds of structured modes produced by the BB. The advantages and challenges that come with the generation and applications of the BB are discussed with examples. This review provides reference material for readers who wish to work with non-diffracting modes and promotes the application of such modes in interdisciplinary research areas.
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.
Open all abstracts, in this tab
Mashaly
In this work, a novel design of a one dimensional photonic crystal (1D PC) is investigated. The 1DPC structure is composed of alternating layers of tantalum pentoxide (Ta2O5) and silicon dioxide (Sio2).The proposed 1D PC structure is designed to act as short wave pass (SWP) edge filter that selectively passes light of short wavelengths, while the infrared light is blocked. In this study, Essential Macleod software is used to create the optimal design with the computational support of the needle synthesis technique. By varying the incidence angle of the mean polarized light mode, we can determine the features of the optimal SWP edge filter design, which leads to an important application for this filter. It can shed light on the filter's suitability as a smart energy saving window coating for hot climate regions. The study includes different hot regions in Saudi Arabia such as Mecca, Riyadh, Dammam, Arar and Alaqiq. They were used as case studies in this research. According to the study of the optimal design of SWP edge filter applied in Mecca, Riyadh, Dammam, Arar and Alaqiq provinces, the light transmittance in the visible region is more than 99% during the summer solstice and more than 96% during the winter solstice. The photonic band gab (PBG) is almost constant during the summer solstice without shifting or decreasing in size whereas in the winter solstice, the PBG shifts toward the short wavelengths and decreases in size by increasing the angle of incidence. This allows an amount of solar energy to enter in winter. Riyadh, Dammam, and Arar provinces experienced a significant increase in solar energy during the winter solstice, more than Mecca and Alaqiq provinces.
Kumar et al
In this research, a new computational approach is presented to address multi-order fractional differential equations, including the renowned Bagley–Torvik and Painlevé equations. These equations are pivotal in scientific and engineering realms, like modelling the movement of a submerged plate restricted in a Newtonian fluid and gas in a fluid, along with simulating the coupled oscillations. We utilise the collocation approach employing a novel operational matrix derived for Morgan-Voyce polynomials via the Atangana-Baleanu fractional derivative. Initially, we introduce the fractional differential matrix to convert the problem and its constraints into a system of algebraic equations with unknown coefficients. These coefficients aid in finding numerical solutions for the given equations. To assess the efficiency of proposed method, various examples are simulated utilising the proposed approach and the outcomes are compared with existing results for different derivatives.
Yao et al
Geometric phase, characterized by its unique properties has been an interesting subject since the discovery of Berry phase. A state inevitably becomes a mixed state in the environment. Uhlmann phase can be applied to mixed states and may be the generalization of Berry phase. In this paper, we use a pair of interacting spin-1/2 fermions, where one particle is influenced by an external magnetic field, while the other remains unaffected, to investigate quantum correlations and Uhlmann phase. Through calculation, we get the specific parameter range q
4+g2 "4+2g2
Zhu et al
A THz wave modulator, utilizing temperature-controlled phase change materials, is proposed to address the limitation of absorbers' inability to adjust to external environments. This modulator enables the switch function of metamaterial absorbers, comprising a gold reflector layer, a silicon dioxide depletion layer, and a vanadium dioxide pattern layer. Simulations via finite element method reveal two nearly perfect absorption peaks, up to 99.99%. As temperature rises, absorption rates increase, stabilizing gradually after vanadium dioxide transitions from insulating to metallic phase. With a modulation depth of 98.49%, the absorber achieves adjustability. It enables polarization-independent absorption of electromagnetic waves, exhibiting strong absorption at incident angles from 0° to 50° for TE and TM waves. Leveraging vanadium dioxide's phase change characteristics, the absorber can switch between ON and OFF states based on temperature changes, promising potential applications in light modulation and THz absorbers.
Turker et al
The topological funneling effect, i. e., the motion of an arbitrary excitation to a focal point of the lattice no matter where the lattice is excited, is a dynamical effect due to the non-Hermitian skin effect. This effect disappears in the presence of strong disorder where the system is topologically trivial. In Anderson localized regime with complex spectrum, the motion shows jumpy behavior and the focal point can be any point along the lattice as it is not possible to say its exact place in an experiment a priori. We study transport phenomena in a non-Hermitian system, exhibiting both funneling effect and non-Hermitian jumps. We show that the competition between the skin and Anderson localizations may result in the creation of an extended eigenstate. This can lead to disorder-induced dynamical delocalization in topologically nontrivial region.
Open all abstracts, in this tab
Mingzhu Li et al 2024 Phys. Scr.
Photons can freely propagate in the vacuum state, so the vacuum is not a trivial insulator, but a conductor for photons. Because of this reason, in topological photonics, the domain wall structures with opposite effective mass terms as a cladding to confine electromagnetic waves have to be adopted to demonstrate the topological edge/surface waves and Fermi arc surface states. In this work, based on the ideal Weyl gyromagnetic metamaterials (GMs), we demonstrate that can be realized the cladding-free Fermi arc surface states with high field localization on the boundary. In the GMs, the ideal Weyl semimetal phase exists due to the dispersionless longitudinal modes. The claddingfree Fermi arc surface states connect the projections of the Weyl points with opposite chirality at the boundary owing to the bulk-edge correspondence of the vacuum-GMs system. Full-wave simulations further demonstrate that that chiral surface waves can seamlessly propagate forward around various types of defects without experiencing scattering or backward reflection. Remarkably, different types of topological directional couplers are achieved by utilizing the cladding-free Fermi arc surface states in the ideal GMs. We theoretically demonstrate that the physical mechanism of realizing the topological directional couplers is caused by the single coupling channel between the cladding-free Fermi arc surface states and scatterers of the vacuum-GMs system. Moreover, the controllable propagation and topological directional coupling of the cladding-free Fermi arc surface states can be realized by changing the gyromagnetic parameters and boundary configurations in the topological directional couplers. Our work could provide more flexibility for the cladding-free and directional coupling topological devices.
Anh-Luan Phan et al 2024 Phys. Scr. 99 075903
We analyze and present applications of a recently proposed empirical tight-binding scheme for investigating the effects of alloy disorder on various electronic and optical properties of semiconductor alloys, such as the band gap variation, the localization of charge carriers, and the optical transitions. The results for a typical antimony-containing III-V alloy, GaAsSb, show that the new scheme greatly improves the accuracy in reproducing the experimental alloy band gaps compared to other widely used schemes. The atomistic nature of the empirical tight-binding approach paired with a reliable parameterization enables more detailed physical insights into the effects of disorder in alloyed materials.
Johannes K Krondorfer et al 2024 Phys. Scr.
Optical nuclear electric resonance (ONER), a recently proposed protocol for nuclear spin manipulation in atomic systems via short laser pulses with MHz repetition rate, exploits the coupling between the nuclear quadrupole moment of a suitable atom and the periodic modulations of the electric field gradient generated by an optically stimulated electronic excitation. In this theory paper, we extend the scope of ONER from atomic to molecular systems and show that molecular vibrations do not interfere with our protocol. Exploring the diatomic molecule LiNa as a first benchmark system, our investigation showcases the robustness with respect to molecular vibration, and the ability to address and manipulate each of the two nuclear spins independently, simply by adjusting the repetition rate of a pulsed laser. Our findings suggest that it might be possible to shift complicated spin manipulation tasks required for quantum computing into the time domain by pulse-duration encoded laser signals.
R Cabrera-Trujillo 2024 Phys. Scr. 99 065416
The compression of an atom produced by two planes induces a change in its electronic structure that evolves from a free atom in 3-D to a 2-D atom. This behavior is of importance in low-dimensional materials and high compression produced by an anvil cell. In this work, we study the evolution of the energy levels and electronic wave-functions of a hydrogen atom placed between two impenetrable planes as a function of the inter-plane separation through a numerical approach. As the inter-plane separation is reduced, the electron motion is restricted along the direction normal to the planes, similar to a particle in a box, while leaving the electron to move unrestricted along the planes, thus, breaking the spherical geometry of the H atom caused by the planes' compression. The energy levels evolve from 3-D, described by nlm quantum numbers to a 2-D described by , where is the quantum number for a particle in a box along the z direction and is the principal quantum number of the 2-D atom radial direction. We evaluate the energy levels from 3-D to 2-D and the radial average distance 〈ρ〉 in cylindrical coordinates, as a function of the inter-plane separation D along the z-direction. We find that as the inter-plane separation is reduced, the angular momentum quantum number l merges to the z-component of the angular momentum and it produces two branches, a symmetric for l-even and one anti-symmetric for l-odd, connected to a particle in a box quantum number along the z-axis with implications in the atom photo-luminescence, resulting from the symmetry of the system. Furthermore, states with l-odd merge with states with l-even, as they have the same energy and average distance when D → 0. We provide an Aufbau principle for it. Our results agree to the analytical solutions at the 3-D and 2-D limiting cases.
Komal Ansari et al 2024 Phys. Scr.
In the last two decades, the ozone layer in the atmosphere has been
depleted, and the sun rays are now more harmful to human skin because
they no longer filters it completely. Long-term exposure to harmful
ultraviolet rays (UV-rays), which have wavelengths between 220nm and
380nm, causes catastrophic damage to skin cells. Sunscreens are
therefore absolutely necessary to protect the skin. The co-precipitation
method was used to synthesize both pure and cobalt-doped zinc oxide
nano structures. In sunscreens, these nanostructures serve as a UV filter.
The obtained nano structures have been characterized by X-ray
diffraction (XRD), scanning electron microscopy (SEM), and diffuse
reflectance spectroscopy (DRS). The ability of a sunscreen sample
containing nano structures to yield results for a period of various hours a t
different temperatures (20°C, 30°C, and 50°C) has been tested.
According to XRD results, prepared samples exhibits hexagonal wurtzite
crystalline structures and are of 22nm in size for pure zinc oxide and 20nm
in size for cobalt-doped zinc oxide. SEM was used to find morphologies,
i.e., nano rods (NRs) at 200nm and 2µm. DRS provided evidence of
sunscreen's endurance, with a 97% absorption of UV-rays at 50°C for up
to 6 hours when incorporated with NRs. In order to boost UV-ray
absorption in sunscreen, nanotechnology has been successfully applied.
Aeriyn D Ahmad et al 2024 Phys. Scr. 99 065562
In this study, we assess the practicality of using Polyacrylonitrile (PAN) as a saturable absorber (SA) for generating Q-switched pulses within an erbium-doped fibre laser (EDFL) cavity. A successful combination of PAN, a resin material, and polyvinyl alcohol resulted in the formation of a SA film. This film was utilised to generate stable Q-switched pulses operating in a long-wavelength band of 1572 nm. The greatest repetition rate achieved was 66.1 kHz, while the minimum pulse width was 2.43 μs. The maximum pulse energy was achieved at 52 nJ and measured at a pump power of 175.9 mW. To the best of our knowledge, this study is the first report of EDFL passive Q-switching employing a PAN absorber.
Chongbin Xi et al 2024 Phys. Scr.
In order to reduce the requirement of system bandwidth of Laser Doppler Velocimeter (LDV), a Dual-Doppler signal mixing LDV is proposed in this paper. By transmitting two beams to the moving surface, two Doppler signals are acquired and subsequently mixed to obtain a difference frequency signal. The measured speed can be calculated based on the frequency of this difference frequency signal. This novel structure significantly reduces the bandwidth requirements on the system, which can be further diminished by minimizing the angle between the two beams of the emitted light. Moreover, it exhibits enhanced robustness against variations in launch angle and enables defocusing measurements.
Vojtěch Skoumal et al 2024 Phys. Scr.
The widespread use of electrospinning, a technique widely used for fabricating micro/nanofibrous materials, has been limited by the high acquisition costs of commercial equipment. This study introduces an accessible alternative by leveraging 3D-printing technology, providing detailed insights into the design and functionality of each component. Specifically, a cost-effective syringe pump, a rotating collector that allows fiber orientation control, and a userfriendly control unit are described. The affordability and customizability of the
proposed setup are emphasized, demonstrating its versatility in accelerating material research. Experimental results on polyvinyl difluoride (PVDF) showcase successful electrospinning, validating the efficacy of the 3D-printed electrospinning device. This innovative solution aims to increase the method's availability and broader utilization in research and development applications.
Sabri M Shalbi et al 2024 Phys. Scr. 99 065049
This study compared ordinary Portland cement (OPC) and Fine Aggregate Graded Polymer (FAGP) samples mixed with 0%, 5%, 10%, and 15% barium sulfate (BaSO4). Theory using the XCOM program and experiments using x-ray fluorescence (XRF) within a specified energy range of 16–25 keV were used to calculate the samples' mass attenuation coefficients. The comparison involved calculating the linear attenuation coefficients (μ/ρ) and attenuation coefficients (μ) of the samples. Both theoretical and experimental results show that the FAGP containing 15% BaSO4 at 16.61 keV has the best attenuation. The findings show that BaSO4 improves radiation shielding. A negative association was found between the attenuation coefficient (μ) and the energy level of radiated radiation. The analysis also found significant concordance between experimental and theoretical methods. In conclusion, the XCOM program had slightly higher mass attenuation coefficients, especially at lower energy levels.
William L Barnes 2024 Phys. Scr. 99 065560
In this report we use material parameters to calculate the strength of the expected Rabi splitting for a molecular resonance. As an example we focus on the molecular resonance associated with the C=O bond in a polymer host, specifically the stretch resonance at ∼1730 cm−1. Two related approaches to modelling the anticipated extent of the coupling are examined, and the results compared with data from experiments available in the literature. The approaches adopted here indicate how material parameters may be used to assess the potential of a material to exhibit strong coupling, and also enable other useful parameters to be derived, including the molecular dipole moment and the vacuum cavity field strength.