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.
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
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.
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.
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.
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.
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.
Stuart Marongwe 2024 Phys. Scr. 99 025306
We introduce quantum spatio-temporal dynamics (QSD) as modeled by the Nexus Paradigm (NP) of quantum gravity to resolve the problem of energy- momentum localization in a gravitational field. Currently, the gravitational field as described using the language of geometry modeled under General Relativity (GR) fails to provide a generally accepted definition of energy-momentum. Attempts at resolving this problem using geometric methods have resulted in various energy-momentum complexes whose physical meaning remain dubious since the resulting complexes are non-tensorial under a general coordinate transformation. In QSD, the tangential manifold is the affine connection field in which energy-momentum localization is readily defined. We also discover that the positive mass condition is a natural consequence of quantization and that dark energy is a Higgs like field with negative energy density everywhere. Finally, energy-momentum localization in quantum gravity shows that a free falling object will experience larger vacuum fluctuations (uncertainties in location) in strong gravity than in weak gravity and that the amplitudes of these oscillations define the energy of the free falling object.
Open all abstracts, in this tab
R Paul et al 2024 Phys. Scr. 99 065602
Dust charging is an arbitrary process occurring at random times which results in fluctuations of dust charge around its equilibrium value. To have a better insight into the mechanism of charge fluctuations, a numerical simulation of the statistical nature of the dust charging process is investigated. Here, a multicomponent non-Maxwellian hydrogen plasma comprising two electron groups, positive ions, and dust grains is modelled. An increase in the overall negative dust charge number is reported in the presence of non-Maxwellian electrons. Additionally, the study emphasizes the role of electron distribution and hot electron temperature and density on the charge fluctuations of the dust grains.
Asifa Ashraf et al 2024 Phys. Scr. 99 065011
This work mainly focuses on unveiling the particle dynamics features of black holes. For this objective, we utilize the charged black hole geometry consisting of the cloud strings and quintessence under the ansatz of Rastall gravity. We have calculated and analyzed the effective potential, angular momentum, particle energy, horizon radius, inner stable circular orbit, photon sphere radius, quasi-periodic oscillations, and effective force to reveal the dynamical features. We in detail discussed the effects of charge in black hole, Rastall parameter, strings of cloud parameter, and quintessential parameter on the calculated results. To ensure the scenario of accelerated expansion, ωq lies in the range −1 < ωq < −1/3. From this specific range, we choose ωq = −2/3.
Lilian Huang et al 2024 Phys. Scr. 99 065217
Compared to conventional single-scroll or double-scroll attractors, multi-scroll chaotic attractors possess wide potential for application due to their adjustability and complex topology. However, neural network models for generating multiple scrolls are often implemented using memristors with piecewise nonlinear functions. To further explore multi-scroll attractors with different working mechanisms,a unique memristor containing a group of hyperbolic tangent functions is designed and then applied in a three-dimensional Hopfield neural network (HNN). The proposed memristive Hopfield neural network (MHNN) has multi-scroll chaotic attractors, where the number and parity of the scrolls be changed by adjusting the control parameters of the memristor. The complex dynamical behaviors of MHNN are studied by utilizing diverse numerical modeling approaches like bifurcation diagrams, Lyapunov exponents and phase plot. In addition, the proposed MHNN also has a complicated offset boosting coexisting behavior. By selecting suitable parameters, multiple coexisting chaotic attractors could be obtained. Homogeneous coexisting multi-scroll attractors can be shifted in multiple directions including unidirectional, planar and spatial ones. Moreover, theoretically speaking, there could be an infinite number of coexisting attractors. Finally, experimental results are validated through numerical simulations and circuit experiments to confirm the feasibility of the proposed MHNN model.
Debamita Roy et al 2024 Phys. Scr. 99 065509
Optoelectronic performance analysis of perpendicularly aligned conformally coated GaAs0.99Bi0.01/ZnO/ITO core–shell nanowire solar cell having a core length of 1 μm, core diameter of 160 nm, shell thickness of 10 nm and period of 280 nm, decorated with Au metal nanoparticles(MNPs) of variable diameters at the core–shell interface is done employing FDTD method. Diameter optimization of MNPs with four different diameters values around core GaAs0.99Bi0.01 nanowire is accomplished in terms of maximum short circuit current density (Jsc), which offered an optimized diameter combination of D1 = D2 = 50 nm and D3 = 34 nm, D4 = 10 nm, resulting in a maximum Jsc of 32.6 mA cm−2. A detailed analysis of the electric field profile including its top view and longitudinal view is presented to investigate the distribution of electric field upon optical illumination at different wavelength range. The overall photo generation rate profile is also presented to focus on the localized surface plasmon resonance effect caused by the metal nanoparticles (MNPs). In order to boost the electrical performance, a thin coating of electron selective ZnO shell is used around p type GaAs0.99Bi0.01core, which aids in charge carrier separation, thereby improving open circuit voltage (Voc) and overall power conversion efficiency (PCE). The electrical characteristics of bare NW and MNP decorated GaAs0.99Bi0.01/ZnO core–shell nanowire solar cell for different MNP diameters have been compared. For the optimized diameter combination, as stated above, a Voc of 941 mV, Jsc of 28 mA cm−2, FF of 84.35% and PCE of 22.19% is obtained for SRV of 105 cm s−1 at the interfaces and SRH recombination lifetime as less as 10 ns. For SRV of 105 cm s−1 at the interfaces and SRH recombination lifetime of 1 μs, this proposed structure can achieve a Voc of 1.06 V, Jsc of 31.5 mA cm−2, PCE of 29.37% and FF of 87.88% for equal diameters of D1 = D2 = D3 = D4 = 50 nm.
Haq Nawab et al 2024 Phys. Scr. 99 065403
We investigate the electromagnetic chirality and negative refraction in a concentric nanoshell of a chiral metal sphere and a chiral atomic shell. The medium of the atomic shell with a four-level system is driven by a laser field and an incoherent pump field in a diamond configuration. We show that the electric and magnetic absorption spectra connecting through the chiral coefficients of the respective dipole moments of the two media, produce five and three lines spectral profiles. We explain that the spectral lines separated by dips are the manifestation of the classical (quantum) coherence effect of the wave field excitation in the medium of the metal sphere (atomic shell), and the interaction of the respective dipole moments at the interface of the two media. Furthermore, we show negative refraction with zero absorption without requiring permittivity () and permeability (μ) simultaneously negative, where for all values of the incident wavelength, Re [μ] ≈ 1, representing a strong chiral electromagnetic behavior. Consequently, the negative refractive index enhances sufficiently beyond n = −1 for a wide range of parameters depending on the coupling parameters, chiral coefficients, and the radii ratio of the concentric metal-atomic nanoshell.
Open all abstracts, in this tab
Chithiika Ruby V and Lakshmanan M 2024 Phys. Scr. 99 062004
Liénard-type nonlinear oscillators with linear and nonlinear damping terms exhibit diverse dynamical behavior in both the classical and quantum regimes. In this paper, we consider examples of various one-dimensional Liénard type-I and type-II oscillators. The associated Euler–Lagrange equations are divided into groups based on the characteristics of the damping and forcing terms. The Liénard type-I oscillators often display localized solutions, isochronous and non-isochronous oscillations and are also precisely solvable in quantum mechanics in general, where the ordering parameters play an important role. These include Mathews-Lakshmanan and Higgs oscillators. However, the classical solutions of some of the nonlinear oscillators are expressed in terms of elliptic functions and have been found to be quasi-exactly solvable in the quantum region. The three-dimensional generalizations of these classical systems add more degrees of freedom, which show complex dynamics. Their quantum equivalents are also explored in this article. The isotonic generalizations of the non-isochronous nonlinear oscillators have also been solved both classically and quantum mechanically to advance the studies. The modified Emden equation categorized as Liénard type-II exhibits isochronous oscillations at the classical level. This property makes it a valuable tool for studying the underlying nonlinear dynamics. The study on the quantum counterpart of the system provides a deeper understanding of the behavior in the quantum realm as a typical -symmetric system.
Dennis Bonatsos et al 2024 Phys. Scr. 99 062003
Prolate to oblate shape transitions have been predicted in an analytic way in the framework of the Interacting Boson Model (IBM), determining O(6) as the symmetry at the critical point. Parameter-independent predictions for prolate to oblate transitions in various regions on the nuclear chart have been made in the framework of the proxy-SU(3) and pseudo-SU(3) symmetries, corroborated by recent non-relativistic and relativistic mean field calculations along series of nuclear isotopes, with parameters fixed throughout, as well as by shell model calculations taking advantage of the quasi-SU(3) symmetry. Experimental evidence for regions of prolate to oblate shape transitions is in agreement with regions in which nuclei bearing the O(6) dynamical symmetry of the IBM have been identified, lying below major shell closures. In addition, gradual oblate to prolate transitions are seen when crossing major nuclear shell closures, in analogy to experimental observations in alkali clusters.
Raghavendra Garlapally et al 2024 Phys. Scr. 99 062002
The present summarized study focused on Anodically fabricated TiO2 nanotubes array shows an exceptional physical and chemical properties due to their high surface area as well as thickness near to nano scale regimes. Crystallization of an amorphous TiO2 nanotube plays an important role when it comes to applications point of view. Studies revealed that a change in the annealing process resulted in an enhancement in their structure and properties. In this review, we mainly focus on various annealing techniques, their advantages and drawbacks over the other methods. Additionally, we have reported the effect of morphology and crystal structure of different annealed anodically grown TiO2 nanotubes. Therefore, the anodized TiO2 nanotubes array review will not only have applications in water splitting, hydrogen generation, solar cells but also a suitable potential candidate in the immense applications as micro/nano needles for drug delivery in biomedical as well as different electronic device/sensing approaches in aerospace sectors as well.
Mohd Shakir Khan et al 2024 Phys. Scr. 99 062001
Efficient energy storage strategies have become a major priority in the last few years. Transition metal sulphides are popularly known as attractive electrode materials or supercapacitors due to their high theoretical capacitance, excellent electrical conductivity, and favourable redox properties. Through compositional and structural engineering, some transition metal sulphides like Mn, V, Co, Fe, Cu, Ni, Mo, Zn, W, and Sn have shown substantial improvements in electrochemical performance. Composite engineering and morphological control are two of the key strategies employed to improve the TMS electrode's electrochemical performance. Excellent electrochemical TMSs address the issues of slow kinetics, poor stability, and large volume expansions. This study reveal optimised TMSs potential to transform supercapacitor applications and provides viable approaches to conquer current hurdles to shape the forthcoming century's high-performance and low-cost energy storage technology. The effects of composite engineering and morphological control on the ultimate electrochemical performance of the electrode materials are the primary focus of this investigation. Challenges to the further advancement of transition metal sulphide-based electrode materials are also explored in this article. Critical approaches to resolving significant issues in our current understanding of the kinetic and mechanistic perspectives of charge storage processes, i.e., slow kinetics, poor stability, and volume expansions, are also highlighted. Ultimately, future potentials, challenges, and possible solutions to tackle these problems are broadly discussed.
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.
Open all abstracts, in this tab
Garg et al
In this work, the possibility of using reduced Graphene oxide for X-ray detection has been explored. A highly conductive reduced Graphene Oxide (rGO) synthesized using a hybrid method was used to fabricate a pixelated Si/SiO2 bottom gate field effect transistor. The fabricated device is a 3x3 pixelated large area detector and was tested for its response to X-rays at roomtemperature and low temperatures by irradiating it with X-rays from top. Significant change in resistance of rGO is observed during irradiation which shows its sensitivity to X-rays.
Hejazi et al
In this work, ZnFe2O4 ferrites were prepared by chemical (coprecipitation) and ceramic (ball-milling) methods. The effects of the synthesis route on the phase purity, crystallinity, particle size distribution, and magnetic properties were investigated to identify the most appropriate conditions for the syhnthesis of high quality ferrites. The samples were exmined by X-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, Fourier transform infrared spectroscopy, vibrating sample magnetometry, and Mössbauer spectroscopy. The XRD patterns revealed that a high-purity spinel phase was obtained by coprecipitation at pH ≥ 7 by calcining the pristine powder at T ≥ 900 °C, whereas a single spinel phase was obtained at T ≥ 700 °C in the ball-milling method. The crystallite size of the spinel phase exhibited general increasing trends with the increase of the pH value under the same heat-treatment conditions, and with the increase of the calcination temperature. Additionally, the mean physical particle size exhibited an increasing trend with the increase of the calcination temperature. The VSM measurements revealed a noticeable degree of inversion in the spinel ferrites prepared by coprecipitation (exhibiting the highest degree at pH = 10), and an insignificant degree of inversion in the spinel ferrites prepared by the ceramic method. However, calcining the powder exhibiting the highest degree of inversion (prepared by coprecipitation at pH = 10) at 1100 °C resulted in ordering the zinc ions at tetrahedral sites of the spinel structure. Mössbauer spectra for representative zinc ferrite samples prepared by the two methods revealed a major central doublet (with a small magnetic sextet corresponding to the α-Fe2O3 phase in the sample at pH = 7). The hyperfine parameters of the doublet observed in the Mössbauer spectra of the samples, and the corresponding magnetization behavior revealed a higher degree of ionic disorder in the spinel ferrite prepared by coprecipitation.
SELLAK et al
The millimeter-wave spectrum has emerged as a compelling solution to address the pressing need for high-datarate
capabilities in the development of 5G technology systems. Spanning between 20 GHz and 40 GHz, this spectrum
encompasses several prominent frequency bands crucial for advancing 5G applications. In light of this, our study
presents a thorough investigation into the design and performance of a compact cross-shaped slot broadband antenna,
complemented by a 4×4 Multiple-InputMultiple-Output (MIMO) configuration tailored for 5G operations at
28 GHz. The primary objective of this study is to develop an antenna system capable of achieving an extended bandwidth
ranging from 20 GHz to 40 GHz, effectively covering the crucial frequency bands essential for 5G millimeterwave(
mmWave) operations. To accomplish this, the optimization of antenna performance is meticulously carried out
using the Radial Basis FunctionNeuralNetworks (RBFNN) model. The RBFNNmodel serves as a robust tool for establishing
the intricate relationship between antenna dimensions, resonant frequency, and bandwidth. Subsequently,
the developed RBFNN model is employed to predict optimal antenna dimensions, ensuring resonance at 28 GHz and
meeting specified bandwidth targets. The single antenna is designed with a rectangular patch and a cross-shaped
slot and is constructed on the low loss Rogers RT Duroid 5880 substrate. This design reaches an outstanding bandwidth
of 19.5 GHz, and exhibits excellent radiation characteristics, with a high radiation efficiency of up to 99% and a
corresponding gain of 5.75 dB. The antenna's design and performance are rigorously designed using HFSS software,
which is then compared to the results acquired using CST software. In addition, the proposed MIMO configuration
offers excellent performance in terms of key features such as small size (16 × 16.2 mm2), very wide bandwidth of 20
GHz, good gain of 6.75 high isolation exceeding 35 dB, and significant improvements in diversity performance measures
such as Envelope Correlation Coefficient (ECC), Diversity Gain (DG), Channel Capacity Loss (CCL), Total Active
Reflection Coefficient (TARC), and Mean Effective Gain (MEG). The potential of the proposed MIMO configuration
for high-speed applications is particularly remarkable. Practical verification of the MIMO configuration is carefully
carried out by fabrication andmeasurement. Experimental results strongly confirmthe effectiveness of the proposed
antenna design, establishing it as a competitive challenger for 5G technology.
TAHIR et al
The hydrothermal approach was used to prepare different proportions of Europium (Eu3+) doped ZnO hybrid material which were characterized by powder X-ray diffraction (PXRD), Scanning electron microscopy (SEM) analysis with end results being Eu3+: ZnO nanocomposites. The XRD pattern obtained verifies the successful incorporation of Europium (Eu3+) into Zinc-Oxide (ZnO) host matrix. SEM analysis predicted that the ZnO was uniformly distributed and agglomeration was observed to be increased with increasing wt.% of Eu3+. The photocatalytic activity was carried out using the antibiotic Rifampicin under visible light and the observed results predicted the highest photocatalytic activity against the antibiotic for Eu3+: ZnO-3 wt.%. Rifampicin had a 90-minute degradation rate of around 90% for Eu3+: ZnO -3 wt.% which demonstrated that doping ZnO with Eu3+ allows a favorable adsorption with enhanced photocatalytic properties. When considering the collective findings of Electrochemical Impedance Spectroscopy (EIS), Photocurrent Measurements and UV-visible spectroscopy data, a unanimous inference can be drawn: the peak photocatalytic efficiency of Eu3+ doped ZnO aligns with a 3% wt. concentration of Europium (Eu3+).
Zhong et al
Ferroelectric photovoltaic materials with intrinsic spontaneous polarization have attracted great attention because the ferroelectric polarization can promote the directional migration of electrons and holes, and reduce the trend of carrier recombination. Recently, the evidence of ferroelectricity in the typical three-dimensional all-inorganic halide perovskites CsGeX3, with band gaps of 1.6 eV to 2.3 eV has been confirmed. But the spontaneous polarization of ferroelectric perovskite CsGeX3 is ~10 to 20 μc/cm2 which is weaker than that of ABO3 (~26 to 75 μc/cm2). Strain engineering has a significant influence on the ferroelectric polarization of semiconductor materials by controlling the lattice scaling and the internal atomic spacing. Hence, in this work, strain engineering is introduced to enhance the ferroelectric polarization and maintain the photovoltaic properties of ferroelectric perovskite CsGeBr3. In this paper, we studied the ferroelectric polarization and photoelectric properties of ferroelectric perovskite CsGeBr3 under different triaxial compressive strain based on first-principle calculations. The calculated results show that when the applied compressive strain increases from 0% to -4%, the spontaneous polarization of ferroelectric perovskite CsGeBr3 increases from 14.23 μc/cm2 to 51.61 μc/cm2, and the band gap reduces from 2.3631 eV to 1.5310 eV. The effective mass of electrons and holes gradually reduces, exciton binding energies decrease from 48 meV to 5 meV, and the optical absorption coefficient is strongly enhanced from 3×105 cm-1 to 5×105 cm-1 in visible range. Besides, the power conversion efficiency(PCE) of CsGeBr3 is significantly increased from 16.95% to 26.77%. Therefore, the results indicate that the application of compressive strain can increase the ferroelectric polarization and even improve the original photovoltaic performance of ferroelectric perovskite CsGeBr3. Our theoretical calculations can provide useful insights and beneficial guidance into experimental studies of ferroelectric perovskites in photoelectric applications.
Open all abstracts, in this tab
Asifa Ashraf et al 2024 Phys. Scr. 99 065011
This work mainly focuses on unveiling the particle dynamics features of black holes. For this objective, we utilize the charged black hole geometry consisting of the cloud strings and quintessence under the ansatz of Rastall gravity. We have calculated and analyzed the effective potential, angular momentum, particle energy, horizon radius, inner stable circular orbit, photon sphere radius, quasi-periodic oscillations, and effective force to reveal the dynamical features. We in detail discussed the effects of charge in black hole, Rastall parameter, strings of cloud parameter, and quintessential parameter on the calculated results. To ensure the scenario of accelerated expansion, ωq lies in the range −1 < ωq < −1/3. From this specific range, we choose ωq = −2/3.
Tom Weber et al 2024 Phys. Scr. 99 065106
The main challenge of quantum computing on its way to scalability is the erroneous behaviour of current devices. Understanding and predicting their impact on computations is essential to counteract these errors with methods such as quantum error mitigation. Thus, it is necessary to construct and evaluate accurate noise models. However, the evaluation of noise models does not yet follow a systematic approach, making it nearly impossible to estimate the accuracy of a model for a given application. Therefore, we developed and present a systematic approach to benchmarking noise models for quantum computing applications. It compares the results of hardware experiments to predictions of noise models for a representative set of quantum circuits. We also construct a noise model containing five types of quantum noise and optimize its parameters using a series of training circuits. We compare its accuracy to other noise models by volumetric benchmarks involving typical variational quantum circuits. The model can easily be expanded by adding new quantum channels.
Dennis Bonatsos et al 2024 Phys. Scr. 99 062003
Prolate to oblate shape transitions have been predicted in an analytic way in the framework of the Interacting Boson Model (IBM), determining O(6) as the symmetry at the critical point. Parameter-independent predictions for prolate to oblate transitions in various regions on the nuclear chart have been made in the framework of the proxy-SU(3) and pseudo-SU(3) symmetries, corroborated by recent non-relativistic and relativistic mean field calculations along series of nuclear isotopes, with parameters fixed throughout, as well as by shell model calculations taking advantage of the quasi-SU(3) symmetry. Experimental evidence for regions of prolate to oblate shape transitions is in agreement with regions in which nuclei bearing the O(6) dynamical symmetry of the IBM have been identified, lying below major shell closures. In addition, gradual oblate to prolate transitions are seen when crossing major nuclear shell closures, in analogy to experimental observations in alkali clusters.
Shuaiqi Zhou et al 2024 Phys. Scr. 99 065213
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. 99 065008
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 favourable outcomes in corrosion resistance, frictional performance, and drilling efficacy during testing.
Leandro Bolzoni and F. Yang 2024 Phys. Scr.
X-ray diffraction (XRD) is routinely used to characterise Ti alloys, as it provides insight on structure-related aspects. However, there are no dedicated reports on its accuracy are available. To fill this gap, this work aims at examining the benefits and limitations of XRD analysis for phase identification in Ti-based alloys. It is worth mentioning that this study analyses both standard and experimental Ti alloys but the scope is primarily on alloys slow cooled from high temperature, thus characterised by equilibrium microstructures. To be comprehensive, this study considers the all spectrum of Ti alloys, ranging from alpha to beta Ti alloys. It is found that successful identification and quantification of the phases is achieved in the majority of the different type of Ti-based alloys. However, in some instances like for near-alpha alloys, the output of XRD analysis needs to be complemented with other characterisation techniques such as microscopy to be able to fully characterise the material. The correlation between the results of XRD analysis and the molybdenum equivalent parameter (MoE), which is widely used to design Ti alloys, was also investigated using structural-analytical models. The parallel model is found to be the best to estimate the amount of β-Ti phase as a function of the MoE parameter.
M A Shukri and F M Thabit 2024 Phys. Scr. 99 065504
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 spherical particle . 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.
Man Li et al 2024 Phys. Scr.
To obtain a highly linearly polarized light, a composite model consisting of white light emission, anti-reflection film, and metal-dielectric-metal nanowire grating was designed, analyzed, optimized, and fabricated. Based on the finite-difference time-domain method, the impacts of material, period, height, and incidence angle on the polarization performance of the composite model were discussed. The metal-dielectric-metal nanowire grating was fabricated on blue chip and fluorescent ceramics using nanoimprint technology. The employed materials of metal-dielectric-metal nanowire grating were aluminum and PMMA, with the period of 200 nm, wire width of 100 nm, and the height of metal and dielectric were 100 nm and 120 nm. Additionally, the anti-reflection film consisting of PMMA with the thickness of 45 nm was incorporated on fluorescent ceramics to enhance energy efficiency. Finally, through a series of test experiments, the composite model can be realized by the extinction ratio of 40 dB, while the transmittance of TM mode exceeds 50% at 450-750 nm. The theoretical analysis of this study is verified by experiments, and it has significant potential in the pursuit of high brightness, ultra-thin micro displays.
Peter Clifford and Raphaël Clifford 2024 Phys. Scr.
Since its introduction boson has been the subject of intense study in the world of quantum computing. In the Fock protocol, the task is to sample independently from the set of all n by n submatrices built from possibly repeated rows of a larger m by n complex matrix according to a probability distribution related to the permanents of the submatrices. Experimental systems exploiting quantum photonic effects can in principle perform the task at high speed. In the framework of classical computing, Aaronson and Arkhipov (2011) showed that exact boson sampling problem cannot be solved in polynomial time unless the polynomial hierarchy collapses to the third level. Indeed for a number of years the fastest known exact classical algorithm ran in O(binomial(m+n-1, n) n 2^n ) time per sample, emphasising the potential speed advantage of quantum computation. The advantage was reduced by Clifford and Clifford (2018) who gave a significantly faster classical solution taking O(n 2^n + poly(m,n)) time and linear space, matching the complexity of computing the permanent of a single matrix when m is polynomial in n.
 
 We continue by presenting an algorithm for Fock boson sampling whose average-case time complexity is much faster when m is proportional to n. In particular, when m = n our algorithm runs in approximately O(n 1.69^n) time on average. This result further increases the problem size required to establish quantum computational advantage via the Fock scheme of boson sampling.
Ibrahim Elbatal et al 2024 Phys. Scr.
In this research, we investigate a brand-new two-parameter distribution as an extension of the
power Zeghdoudi distribution (PZD). Using the inverse transformation technique on the PZD, the
produced distribution is called the inverted PZD (IPZD). Its usefulness in producing symmetric and
asymmetric probability density functions makes it the perfect choice for lifetime phenomenon mod-
eling. It is also appropriate for a range of real data since the relevant hazard rate function has one of
the following shapes: increasing, decreasing, reverse j-shape or upside-down shape. Mode, quantiles,
moments, geometric mean, inverse moments, incomplete moments, distribution of order statistics,
Lorenz, Bonferroni, and Zenga curves are a few of the significant characteristics and aspects explored
in our study along with some graphical representations. Twelve effective estimating techniques are
used to determine the distribution parameters of the IPZD. These include the Kolmogorov, least
squares (LS), a maximum product of spacing, Anderson-Darling (AD), maximum likelihood, mini-
mum absolute spacing distance, right-tail AD, minimum absolute spacing-log distance, weighted LS,
left-tailed AD, Cram ́er-von Mises, AD left-tail second-order. A Monte Carlo simulation is used to
examine the effectiveness of the obtained estimates. The visual representation and numerical results
show that the maximum likelihood estimation strategy regularly beats the other methods in terms of
accuracy when estimating the relevant parameters. The usefulness of the recommended distribution
for modelling data is illustrated and displayed visually using two real data sets and comparisons with
other distributions.