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.
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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.
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.
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.
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.
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?
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.
Roland E Allen and Suzy Lidström 2017 Phys. Scr. 92 012501
In The Hitchhiker's Guide to the Galaxy, by Douglas Adams, the Answer to the Ultimate Question of Life, the Universe, and Everything is found to be 42—but the meaning of this is left open to interpretation. We take it to mean that there are 42 fundamental questions which must be answered on the road to full enlightenment, and we attempt a first draft (or personal selection) of these ultimate questions, on topics ranging from the cosmological constant and origin of the Universe to the origin of life and consciousness.
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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Farah B H Pritu et al 2024 Phys. Scr. 99 065904
Spintronics and optoelectronic equipment benefit from efficient modification of electrical and optical characteristics for Van der Waals heterostructures. Janus MoSSe, in two dimensions, has superior electronic, optical, and phonon properties. Based on these characteristics, we evaluate the effects of biaxial compressive and tensile strain ranges of −6% to +6% on the structural, optical, spin–orbit coupling, and phonon properties of two-dimensional MoSSe employing first-principles-based density functional theory calculations. At K-point, MoSSe possesses a direct band gap of 1.665 eV, making it a semiconductor. Yet, applying tensile strain, we can observe that the bandgap of MoSSe has declined. On the other hand, the bandgap of MoSSe rises due to the compressive strain. From the phonon properties, it is clear that the stability of the monolayer MoSSe is observed in the case of tensile strain. With the increase of compressive strain, it loses its stability. With a photon energy of 2.5 eV, MoSSe exhibits three times greater optical absorption than other photon energy levels. In comparison to two monolayers (MoS2, MoSe2), the MoSSe heterostructure shows an elevated optical absorption coefficient in the visible light band, according to our calculations of its dielectric constant and optical absorptionThe MoSSe dielectric constant's peaks shift to the stronger photon energy as compressive strain is increased; in contrast, if tensile strain is added, the highest points shift to the less powerful photon energy. This suggests that the spin–orbit coupling (SOC) in MoSSe heterostructures can be enhanced under strain, which has implications for spintronics. The effect of strain can be used to tailor the phonon behaviors of MoSSe, which can be useful for controlling the material's mechanical and thermal characteristics. The versatility of the electronic and optical properties of the material under strain can be harnessed to design novel devices such as strain sensors, optoelectronic modulators, and detectors.
Srishti et al 2024 Phys. Scr. 99 065202
This paper presents the design of the transfer function between the control and output variable of a DC-DC boost converter using a combination of Proportional Integral Derivative (PID) and output-based Model Predictive Control (MPC) mechanisms for eradicating the effect of the non-minimum phase (NMP) behavior on the system. This is made possible due to the existence of a right half plane (RHP) zero. It is observed that the MPC outperformed the conventionally designed PID approach by a significant margin. Based on the computed results, it can be emphasized that the combination of output-based MPC and PID controller demonstrated a strong alignment with optimal designs, exhibiting a fast convergence rate than PID and PID-IMC. Simulation results are presented to showcase the fast transient response and a high level of robustness of the proposed control methodology.
Min Zheng et al 2024 Phys. Scr. 99 065001
The study investigated the nanofabrication behavior of TiAl alloys with a duplex structure of γ/α2. The process included downward pressure followed by reciprocating friction with diamond grinding balls and was simulated using molecular dynamics (MD). It was found that a certain number of dislocations in the workpiece was low, and the resilience was high during the initial pressing stage. The dislocations increased, the resilience decreased, and the plastic deformation capacity was enhanced under continuous pressing. The α2 phase did not deform significantly during the compression process. The presence of the α2 phase increases the overall hardness of the material, and elastic-plastic deformation occurs mainly where the γ phase is present; the endowment layer dislocations generated during the intrinsic stacking fault rebound via the phase boundary to form V-shaped dislocations. During the reciprocating friction of the workpiece, forward friction produces V-shaped dislocations, and reverse friction makes the dislocations disappear. This process results in the forward average friction force being more significant than the reverse average. γ/α2 phase boundary has an impeding effect on the downward proliferation of defects, and the phase boundary makes the temperature transfer appear discontinuous. During friction, the specific number of vacancy atoms in the γ-phase increases, and the transition between FCC and HCP occurs.
Choon-Lin Ho 2024 Phys. Scr. 99 060401
We give a brief overview of a simple and unified way, called the prepotential approach, to treat both exact and quasi-exact solvabilities of the one-dimensional Schrödinger equation. It is based on the prepotential together with Bethe ansatz equations. Unlike the the supersymmetric method for the exactly-solvable systems and the Lie-algebraic approach for the quasi-exactly solvable problems, this approach does not require any knowledge of the underlying symmetry of the system. It treats both quasi-exact and exact solvabilities on the same footing. In this approach the system is completely defined by the choice of two polynomials and a set of Bethe ansatz equations. The potential, the change of variables as well as the eigenfunctions and eigenvalues are determined in the same process. We illustrate the approach by several paradigmatic examples of Hermitian and non-Hermitian Hamiltonians with real energies. Hermitian systems with complex energies, called the quasinormal modes, are also presented. Extension of the approach to the newly discovered rationally extended models is briefly discussed.
Dingkang Mou and Yumin Dong 2024 Phys. Scr. 99 065201
To enhance the security of image data, prevent unauthorized access, tampering, and leakage, maintain personal privacy, protect intellectual property rights, and ensure the integrity of images during transmission and storage. This study introduces an innovative color image encryption scheme based on dynamic DNA encoding operations and chaotic systems. By simulating a quantum random walk, a random key is generated to enhance the security of the confidential system. In addition, we integrated the enhanced Josephus problem into DNA coding rules to create dynamic DNA coding rules. At the same time, we proposed a dynamic double-loop DNA XOR operation, which fully utilizes the random sequence generated by the generalized Hamiltonian chaos system to precisely control the loop direction, starting point, and number of operations. This enhances the complexity of the encryption algorithm. After sufficient experimental verification and in-depth research and analysis, our innovative design not only enhances the difficulty of cracking while ensuring image quality but also provides reliable protection for the security of image data.
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Chenyan Huang et al 2024 Phys. Scr. 99 052004
Noise pollution is an important problem affecting people's lives and work quality. In the current noise reduction materials, the porous sound absorption materials usually only haveagood sound absorption effect for medium and high -frequency sound waves, and the sound absorption effect for low -frequency sound waves is relatively weak. However, in recent years, the research on acoustic metamaterials has made a breakthrough which can effectively absorb or isolate low-frequency sound waves. Therefore, researchers propose to combine porous sound-absorbing materials with acoustic metamaterials to form a composite structure, that broadens the frequency range of noise reduction, so as to achieve the goal of full-frequency domain noise reduction. This paper first introduces the research progress of porous materials and acoustic metamaterials, and then introduces the research progress of composite structures that are made of porous materials and acoustic metamaterials. Finally, the application prospect of the composite field of porous sound-absorbing materials and acoustic metamaterials are summarized.
Sonal Santosh Bagade and Piyush K Patel 2024 Phys. Scr. 99 052003
To achieve efficient solar cells, an in-depth review on significance of diffusion length enhancement is presented in this research work. We have focused on globally-adopted strategy of increasing diffusion length. The experimental pathways followed by various researchers to realize this strategy are deeply explored in this paper. The total of nine key-parameters that control and facilitate diffusion length enhancement are identified. Moreover, total of four parameters which are primarily influenced by diffusion length enhancement are listed. The underlying cause-&-effect mechanism pertaining to each parameter is discussed in-depth in this article. Furthermore, the comparison is performed between impact of electron and hole diffusion length enhancement on the device performance. The way to potentially implement this study for appropriate absorber layer selection is presented. Finally, a comparative study is performed on extent of influence of diffusion length enhancement technique to that of the band-offset optimization technique to achieve higher device performance. This rigorous analysis leads to discovery of the fact that diffusion length enhancement raises solar cell efficiency seven times as compared to that obtained by band offset optimization. Hence, significance of diffusion length enhancement for the pinnacle performance of solar cell is vividly revealed in this paper.
Theivasanthi Thirugnanasambandan et al 2024 Phys. Scr. 99 052002
The development of advanced materials, new device architectures and fabrication processes will lead to more utilization of renewable energy sources like solar energy. Solar energy can be harvested more effectively using solar cells incorporated with advanced nanomaterials. Black phosphorus (BP) is a two-dimensional material in which the layers are stacked together through van der Waals forces. The electrical and optical properties of the material are much more suitable for use in solar cell applications. BP nanosheets have optoelectronic properties such as tunable bandgap (0.3 eV − 2.0 eV) and high carrier mobility that make them as suitable candidates for solar cells. Also, BP is able to absorb a wide range of light energy in the electromagnetic spectrum. Being a p-type semiconductor, BP finds applications in optoelectronic and semiconductor- devices. The optical absorption of the material is determined by its structural orientation. The material also possesses the high in-plane anisotropic band dispersion near the Fermi level in the Brillouin zone which results in a high direction-dependent optical and electronic properties. The major limitation of the material is its stability since it is degraded under the illumination of light. BP is used as an electron transport layer in solar cells similar to ZnO, TiO2 and graphene. BP can also be integrated with hole transport layers and active materials. Research efforts have shown that BP and its derivatives have more potential to produce high efficiency solar cells. The application of BP in various solar cells and the enhancement in the efficiency of solar cells such as organic solar cells, perovskite solar cells, dye-sensitized solar cells and silicon solar cells are discussed in this review.
Raghuraman V and Sampath Kumar T 2024 Phys. Scr. 99 052001
The laser powder bed fusion LPBF method in additive manufacturing for metals have proven to produce a final product with higher relative density, when compare to other metal additive manufacturing processes like WAAM, DED and it takes less time even for complex designs. Despite the use of many metal-based raw materials in the LPBF method for production of products. Maraging steel (martensitic steel) is used in aeronautical and aircraft applications in view of its advantages including low weight, high strength, long-term corrosion resistance, low cost, availability, and recyclability. A research gap concerns the selection of design, dimension, accuracy, process parameters according to different grades, and unawareness of various maraging steels other than specific maraging steels. In this comprehensive review, the research paper provides information about on LPBF maraging steel grades, their process parameters and defects, microstructure characteristics, heat treatments, and the resulting mechanical characteristics changes. In addition, detailed information about the aging properties, fatigue, residual and future scope of different maraging steel grades in LPBF for various applications are discussed.
Joy Chowdhury et al 2024 Phys. Scr. 99 042001
The progress in IC miniaturization dictated by Moore's Law has taken a leap from mere circuit integration to IoT enabled System-on-Chip (SoC) deployments. Such systems are connoted by contemporary advancements in the semiconductor industry roadmaps namely, 'More-Moore' and 'More-than-Moore' (MtM). For meaningful integration of digital and non-digital blocks, a power performance tradeoff is essential for maximum and fruitful utilization of the silicon area. Using the techniques under the MtM nomenclature allows the use of unconventional steep slope devices like Tunneling FETs, Negative Capacitance (NC) FETs, Gate-all-around FETs (GAA) and FinFETs etc, which can exhibit reasonable performance with lower supply voltages. Following the Device Technology Co-optimization (DTCO) and System Technology Co-optimization (STCO) the advanced 3D heterogenous integration technologies allow sensors, analog/mixed signal and passive components to be assimilated within the same package as the CMOS blocks. Appropriate device engineering techniques like multi-gate architectures, vertical stacking transistors, compound semiconductors and alternate carrier transport phenomena are required to improve the current drive and scaling performance of advanced CMOS devices. CMOS based codesign is essential to realize new topologies for energy economical computation, sensing and information processing as the beyond CMOS steep slope devices are independently incapable of replacing conventional bulk CMOS devices. This article presents a detailed qualitative review of the various aspects of MtM beyond CMOS steep slope switches and their prospective integration technologies. For system level integration, various aspects of device performance and optimizations, related device-circuit interactions, dielectric technologies at the advance nanometer nodes have been probed into. Additionally, novel circuit topologies, synthesis algorithms and processor level performance evaluation using steep slope switches have been investigated. An exclusive compact overview for contemporary insights into integrated device-system development methodology and its performance evaluation is presented.
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Hernández-León et al
We present a new technique for visualizing high-dimensional data called cluster MDS (cl-MDS), which addresses a common difficulty of dimensionality reduction methods: preserving both local and global structures of the original sample in a single 2-dimensional visualization. Its algorithm combines the well-known multidimensional scaling (MDS) tool with the k-medoids data clustering technique, and enables hierarchical embedding, sparsification and estimation of 2-dimensional coordinates for additional points. While cl-MDS is a generally applicable tool, we also include specific recipes for atomic structure applications. We apply this method to non-linear data of increasing complexity where different layers of locality are relevant, showing a clear improvement in their retrieval and visualization quality.
Tawfeek et al
We present a comprehensive analysis of barred galaxies within two distinct samples: isolated single galaxies (SIG) and isolated galaxy pairs (SIP), drawn from the SDSS-based catalog of isolated galaxies and the catalog of isolated galaxy pair limited to M $\leq$ $-$18.5, respectively. Our primary aim is to investigate the influence of tidal effects on the bar fraction ($f_{bar}$) across various galaxy systems. Barred galaxies are identified through automated ellipse fitting analysis supplemented by visual inspection of r-band imaging. A strong correlation between $f_{bar}$ and both galaxy morphological type and star formation rate has been revealed. Although, barred galaxies represent a nearly equal percentage of 52$\%$ in SIG and 51$\%$ in SIP, we found a little evidence for the tidal dependence of bar formation where a notable increase in the $f_{bar}$ is observed among galaxies characterized by larger projected separation and higher radial velocity difference between the pair members. In SIGs, we observe a prevalent increasing trend of $f_{bar}$ with galaxy mass, contrasting the observed decrease in $f_{bar}$ with increasing galaxy mass in SIPs. This discrepancy is consistent with typical trends of weaker bars, suggesting that tidal effect may attenuate the strength of bar structures within galaxy pairs.
Venkatesan et al
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 fiberoptic 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.
AlHumairee et al
Blend polymer matrix composite materials are becoming more and more popular due to their promising mechanical properties. In this research, a blend polymer mixture was made from epoxy resin (EP) blended with different weight percentages of PSR (polysulfide rubber) (0, 3, 6, 10, 15, and 20%). Then tensile, impact, bending strength, and damping ratio evaluated to get the high quality of mechanical properties for the blend matrix. Due to the requirements to enhance the mechanical properties of this blend; a various weight fraction of carbide silica (SiC) nanoparticles was used as a reinforcement in the ratios of (0, 1, 3, and 5%) by weight to the best ratio of the blended matrix. Tensile, impact, bending, and damping ratio tests also conducted to get the best mechanical properties for the blended materials. Experimental results for the blend matrix showed that adding polysulfide rubber to epoxy resin resulted in a decrease in Young's modulus, tensile strength, and bending strength; however, the damping ratio and the impact strength increased. It found that the weight fraction of 6% of PSR is the better case, which gives the better mechanical properties for mixture. The utility of this mixture; it has intermediates between flexible properties of a mixture at the highest rate of PSR and brittle mechanical properties for EP resin. Mechanical and damping properties showed an increase when the carbide silica (SiC) with a weight fraction of 3% was added, then it decreased slightly.
Jafarova et al
Doping effects on the electronic and magnetic properties of Zn1-x(Co,Cr)xO systems are investigated within Local Spin Density Approximation and Hubbard U methods. Based on Density Functional Theory the spin-polarization band structures, density of states for investigated systems are calculated. Systematic analysis of the electronic properties shows that TM-doped ZnO has generated new energy levels in the vicinity of Fermi energy level. From first-principle calculations we obtained Cr-ZnO and Co-ZnO systems are metallic and half-metallic ferromagnetic materials, respectively. The obtained results for Cr-doped ZnO 128- and 192-atom supercell systems show magnetic properties with higher Curie temperature than room temperature. There are large local moments, ~2.9 and ~4.2 for Co and Cr dopants, respectively. Magnetic moments are related with two electron defects in the supercell structure and unpaired electrons of transition metal. The ferromagnetic and antiferromagnetic phases and the total energy are obtained for x=2.08 %, 3.125 %, 4.16 %, 6.25 %, 8.3 %, 12.5 %, and 25 % impurity concentrations for doped ZnO.
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Ayten Özkan 2024 Phys. Scr. 99 055269
In this study, the fractional impacts of the beta derivative and M-truncated derivative are examined on the DNA Peyrard-Bishop dynamic model equation. To obtain solitary wave solutions for the model, the Sardar sub-equation approach is utilized. For a stronger comprehension of the model, the acquired solutions are graphically illustrated together with the fractional impacts of the beta and M-truncated derivatives. In addition to being simple and not needing any complicated computations, the approach has the benefit of getting accurate results.
V K Anand et al 2024 Phys. Scr. 99 055977
CeRh2Ga2, which crystallizes in CaBe2Ge2-type primitive tetragonal structure (space group P4/nmm), is known to exhibit Kondo lattice heavy fermion behavior and is proposed to be a potential candidate for Weyl-Kondo semimetal phase. Here we examine the effect of annealing, particularly on the electrical resistivity of polycrystalline CeRh2Ga2. A comparative study of the powder x-ray diffraction (XRD), magnetic susceptibility χ(T), heat capacity Cp(T) and electrical resistivity ρ(T) data of both as-arc-melted and annealed CeRh2Ga2 samples are presented. The XRD patterns of both as-arc-melted and annealed samples look similar. No marked effect of annealing could be clearly seen in the temperature dependences of χ and Cp data. However, the effect of annealing is clearly manifested in the T dependence of ρ, particlularly at low temperatures. At low-T the ρ(T) data of as-arc-melted CeRh2Ga2 follow a T2 temperature dependence (Fermi-liquid feature), whereas the ρ(T) data of annealed CeRh2Ga2 exhibit an upturn (semimetal-like feature).
Patricia Hernández-León and Miguel Caro 2024 Phys. Scr.
We present a new technique for visualizing high-dimensional data called cluster MDS (cl-MDS), which addresses a common difficulty of dimensionality reduction methods: preserving both local and global structures of the original sample in a single 2-dimensional visualization. Its algorithm combines the well-known multidimensional scaling (MDS) tool with the k-medoids data clustering technique, and enables hierarchical embedding, sparsification and estimation of 2-dimensional coordinates for additional points. While cl-MDS is a generally applicable tool, we also include specific recipes for atomic structure applications. We apply this method to non-linear data of increasing complexity where different layers of locality are relevant, showing a clear improvement in their retrieval and visualization quality.
Christopher R Martin et al 2024 Phys. Scr. 99 055609
This simplified model provides solutions for the current-voltage characteristics of a sheath in a dense flowing plasma when surface chemistry contributes secondary ions. The problem is motivated by the recent discovery that strong transient signals in industrial ion current sensors are caused by chemical reactions with carbon in the steel being cut or welded by oxyfuel processes. The one-dimensional model considers a quasi-uniform dense plasma flowing towards and stagnating on an absorbing surface, above which there is a source of secondary ions. Because the secondary ions are formed directly in the plasma sheath, they have strong impacts on the current-voltage characteristic. With ionic Reynolds number, R, and integral length scale, α, secondary ion formation rate, Ω, and length scale, β, saturation currents are simply R + βΩ until β ≪ 1, at which point, new electrons cannot escape the sheath, and secondary ions have no effect. Floating potential, ϕ∞, scales like , and secondary ions have little impact unless β2Ω > 1. Even then, floating potential is only weakly affected by secondary ion formation. The integral length scale, α, is not found to strongly affect the results.
Yong Wang et al 2024 Phys. Scr.
Cascaded arc plasma has been widely applied in linear plasma devices (LPDs) to produce high flux plasma for the study of plasma-material interaction. In this work, cascaded arc He plasma produced in an LPD with a compact arrangement is investigated by voltammetry and optical emission spectroscopy (OES). The results show that the cathode potential increases with the discharge current while it firstly decreases and then increases as increasing the gas flow rate. A local reverse electric field is observed at low gas flow rates between two cascaded plates (i.e. floating electrodes) near the cathode. The OES' results reveal that as the gas flow rate increases, the intensity of He I lines increases and the electron excitation temperature (Texc) decreases. As increasing the discharge current, the intensity of He lines exhibits various trends at different gas flow rates, showing a monotonic decline at 1.94 slm and a first increase followed by a reduction at 3.52 slm. The Texc increases with the discharge current. These findings could preliminarily shed light on the properties of cascaded arc of He plasma in the compact LPD and aid in the optimization of the device to generate the high-flux divertor-relevant plasma.
Y. B Ateş and Eser Olgar 2024 Phys. Scr.
The effect of isotropic velocity-dependent potentials on the bound state energy eigenvalues of the Kratzer, Mie and Hulthen potentials is obtained for any quantum states in the presence of constant form factor ε(r)=γρ_0. The corresponding energy eigenvalues and eigenfunctions are determined for any quantum numbers n and l in the framework of the well-known Nikiforov-Uvarov method. 
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.
Shuaiqi Zhou et al 2024 Phys. Scr.
Abnormal behaviours in crowded populations can pose significant threats to public safety, with the occurrence of such anomalies often corresponding to changes in macroscopic quantities of the complex system. Therefore, the automatic extraction and prediction of macroscopic quantities in pedestrian collective behaviour becomes significant. In this study, we generated pedestrian evacuation data through simulation, and calculated the average kinetic energy, entropy and order parameter of the system based on principles of statistical physics. These macroscopic quantities can characterize the changes in crowd behaviour patterns over time and can also assist in detecting abnormalities. Subsequently, we designed deep convolutional neural networks(CNNs) to estimate these macroscopic quantities directly from frame-by-frame image data. In the end, a convolutional auto-encoder(CAE) model is trained to learn the underlying physics unsupervisedly. Successful results indicate that deep learning methods can directly extract macroscopic information from crowd dynamics, aiding in analysing collective behaviour.
M Shanmuka Srinivas et al 2024 Phys. Scr.
As industries worldwide seek environmentally sustainable solutions, the metalworking sector faces a growing need for eco-friendly alternatives to traditional cutting fluids. This abstract introduces the concept of an innovative approach to cutting fluid technology – the use of groundnut oil as a base material for machining fluids. Derived from peanuts, groundnut oil presents a renewable and biodegradable alternative to petroleum-based counterparts, addressing concerns related to resource depletion and environmental impact. A comprehensive performance evaluation of groundnut oil- based cutting fluid has been carried out by series of critical tests such as separation testing, particle size and stability testing, frictional testing, corrosion testing and drilling testing. The results of these tests collectively contribute to a comprehensive understanding of groundnut oil-based cutting fluids, shedding light on their potential as sustainable and high-performance alternatives in metalworking. The zeta potential for the prepared green cutting fluid has been found to be 49.10 mV. The dimensions of the dispersed particles in a fluid of the cutting fluid have been found as 250-260 nm. The environmentally friendly cutting fluid exhibits favorable outcomes in corrosion resistance, frictional performance, and drilling efficacy during testing.
M. A. Shukri and F. M. Thabit 2024 Phys. Scr.
An analytical expression for the intensity distribution of a focused continuous Hermite-Gaussian beam after passing through a positive lens has been derived. Analytically, this intensity has been used to derive the gradient force acting on a nano-dielectric particle sphere. It is found that, the beam modes (p, l) have a direct influence on the trap stability, the number of trapping regions, the area of trapping zones and the particle size range.