Physica Scripta

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.

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.

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.

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.

We offer a quantum chemical analysis of mono-halogenated borane molecules using DFT and TD-DFT theories, applying the PBE0/def2-SVPD and B3LYP/6-311+G(d) methods as implemented in ORCA, and explore how solvent effects influence electronic transition properties. The comparable benchmarks are the archetype anti-B₁₈H₂₂ denoted as (1) against hypothetical halogenated derivatives: 7-F-anti-B₁₈H₂₁ (2), 4-F-anti-B₁₈H₂₁ (3), and the recently synthesized 4-Br-anti-B₁₈H₂₁ (4). The analysis includes an optimization of the ground and first singlet excited states, vibrational frequency analysis, and a comprehensive spectroscopic profile covering IR, Raman, UV-Vis absorption, and emission spectra. The IR spectra of the fluorinated compounds feature a characteristic B-F stretching peak, while the Raman spectra closely resemble the parent molecule. UV-Vis spectral analysis shows a redshift and oscillator strength enhancement for F at position B7, indicating altered electronic properties due to substitution with lighter halogen. Furthermore, solvent effects enhance the probability of electronic transitions. Halogene presence led to a decrease of the energy gap EG(LUMO-HOMO) due to the stabilization of LUMO, which implied a redshift in the emission/absorption wavelength spectra, with the largest EG change at around 14% occurring for the (4)th benchmark compound.. Notably, all compounds emit light within the visible spectrum, underscoring their potential for optoelectronic applications.

Alena Tensor is a recently discovered class of energy-momentum tensors that provides mathematical framework in which, as demonstrated in previous publications, the description of a physical system in curved spacetime and its description in flat spacetime with fields are equivalent. The description of a system with electromagnetic field based on Alena Tensor can be used to reconcile physical descriptions. (1) In curvilinear description, Einstein Field equations were obtained with Cosmological Constant related to the invariant of the electromagnetic field tensor, which can be interpreted as negative pressure of vacuum, filled with electromagnetic field. (2) In classical description for flat spacetime, three densities of four-forces were obtained: electromagnetic, against gravity (counteraction to gravitational free-fall), and the force responsible for the Abraham-Lorentz effect (radiation reaction force). Obtained connection of Einstein tensor with gravity and radiation reaction force, after transition to curvilinear description, excludes black hole singularities. There was obtained Lagrangian density and generalized canonical four-momentum, containing electromagnetic four-potential and a term responsible for the other two forces. In this description charged particles cannot remain at complete rest and should have spin, their energy results from the existence of energy of magnetic moment and the density of this energy is part of the Poynting four-vector. The distribution of charged matter was expressed as polarization-magnetization stress-energy tensor, what may explain why gravity is invisible in QED. 3) In quantum picture, QED Lagrangian density simplification was obtained, and the Dirac, Schrödinger and Klein–Gordon equations may be considered as approximations of the obtained quantum solution. Farther use of Alena Tensor in unification applications was also discussed.

In this study, we focused on a FePtAu-C small-grain film specifically designed for very-high density perpendicular magnetic recording media, surpassing 1 Tbits/in² density. The film layer had a composition of Fe₄₇Pt₄₃Au₁₀-C40% with 7.2 nm thickness. It was deposited onto a silicon substrate with one 12 nm thick magnesium oxide sandwich-layer at 560 °C temperature. Notably, the film exhibited a perpendicular coercivity of 39 kOe. Based on transmission electron microscopy (TEM) analysis, the film small-grain size was determined to be approximately 8.2 ± 1.6 nm. Furthermore, our investigation revealed that the grain size of magnesium oxide sandwich-layer was about 12 nm, which was larger than that of FePt. As a consequence, the FePt small-grains were not directly influenced by magnesium oxide small-grains beneath them. Moreover, a more in-depth examination using high-resolution TEM imaging demonstrated outstanding L1₀ ordering within the thin-film, corroborated by texture examination conducted via x-ray diffraction (XRD). It is noteworthy that magnesium oxide sandwich-layer exhibited a polycrystalline structure, while the FePt growing on top of magnesium oxide occurred in an epitaxial manner.

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.

Bragg reflection waveguides (BRW) enable the generation of photon pairs in non-birefringent AlGaAs through spontaneous parametric down conversion (SPDC). Furthermore, the development of an electrically driven laser source from a passive BRW by introducing a suitable doping profile and an active region allows the simultaneous lasing of the pump field and the SPDC process within the same cavity. Here, we present an optimized design of a BRW to allow lasing at 775 nm and simultaneous conversion into photon pairs at 1550 nm. Based on the computed modes at 775 nm and 1550 nm, the non-linear emission characteristics of both SPDC and second harmonic generation of the proposed device is calculated. The design is particularly optimized regarding the monolithic integration of a distributed Bragg reflector (DBR) section to stabilize the laser wavelength. This is necessary because SPDC is highly sensitive to the pump wavelength. By using an eigenmode expansion approach, we calculate the reflection spectra of a 1 mm long, 9th order surface grating in dependence of various parameters. We demonstrate that a peak reflectivity of  > 80% can be achieved with technologically feasible etch depths and groove widths. This paves the way for the promising application of DBR surface gratings for the selection of the pump wavelength for the SPDC process in BRW lasers, with the objective of improving the photon output.

In this work, strange quark matter (SQM) and normal matter (NM) attached to domain wall (DW) matter distributions have been examined for locally rotationally symmetric (LRS) Bianchi-I space-time has been investigated. The model has been constructed in the framework of f(R, T) theory for f(R, T) = R + 2μT which is suggested as an alternative gravitation theory instead of Einstein's General Relativity Theory. Obtained modified field equations have been solved by using scale factors equation A = B^m come from the proportion of expansion scalar θ to shear scalar ϖ². SQM and NM are added to DW with the help of equations of state (EoS) ${p}_{m}=\frac{1}{3}({\rho }_{m}-4{B}_{c})$ and p_m = (γ − 1)ρ_m. Pressure and energy densities of all matter distributions have been obtained depending on cosmic time t and their effects decrease by the time. It is found that DW matter behaves like stiff matter due to attaining DW pressure equal to DW energy density p^DW = ρ^DW. Also obtained values of scale factors and some kinematic quantities give an expanding universe for the model. Energy conditions and kinematic quantities of the model have been examined in the last section. In addition, General Relativity solutions of the model have been attained by assuming μ = 0 in f(R, T) = R + 2μT. All solutions have been concluded in detail.

Rainfall forecasting is crucial for disaster mitigation, agriculture, and water resource management. However, due to the dynamic nature of weather patterns, predicting rainfall remains a complex challenge. Various meteorological factors influence rainfall, necessitating an effective selection process to identify the most significant parameters. This study introduces a novel approach for parameter selection in rainfall forecasting by integrating two Multi-Criteria Decision-Making (MCDM) techniques: Fuzzy Analytic Hierarchy Process (FAHP) and Fuzzy Technique for Order Preference by Similarity to Ideal Solution (FTOPSIS). The proposed method prioritizes key meteorological factors that have the greatest impact on occurrence of rainfall and enhancing forecasting precision. The selected parameters contribute to improving rainfall prediction accuracy, reducing errors, and providing a reliable foundation for advanced forecasting models.

We develop the discrete uncertainty principle of the Fourier transform on a finite non-Abelian group. Furthermore, we define the Zak basis and subsequently define the finite Zak transform on a finite non-Abelian group. Analogous to the conventional finite Zak transform, various properties of the Zak transform are studied, and the sparsity of the Zak transform is illustrated through its discrete uncertainty principle. It is proven that the Zak transform partially diagonalizes the left regular representation into a block diagonal matrix. A few applications of the Zak transform concerning quantum information theory and Cayley graphs are discussed. It is observed that the Zak transform characterizes a completely positive and trace-preserving operator. Finally, we prove that the Zak basis forms the eigenvectors of the adjacency operator of quasi-Abelian Cayley graphs.

Malaria continues to be a significant global health threat, with periodic outbreaks of varying severity due to Plasmodium infections transmitted by Anopheles mosquitoes. This paper introduces an improved malaria epidemic model, which incorporates the influence of Wolbachia and temperature. And the paper shows that both the disease-free and endemic equilibrium solutions exhibit periodic fluctuations influenced by temperature, aligning with the seasonal patterns observed in malaria transmission, which could explain real-world disease transmission. Additionally, the rigorous dynamical analysis is conducted using Poincaré mapping, periodic semiflow theory and Floquet theory. Specifically, the asymptotic stability of the disease-free periodic solution and the existence of positive periodic solutions are demonstrated in this paper. Finally, numerical simulations corroborate these theoretical results, it is emphasized that the mosquito population will eventually be infected with wolbachia, which has important significance for malaria control.

Nanoporous Gallium Nitride (GaN) distributed Bragg reflectors (DBRs) have emerged as a promising component in advanced optical devices, offering significant improvements in performance due to their unique structural and optical properties. This review provides a comprehensive overview of the recent progress in the properties, fabrication techniques, and application of nanoporous GaN DBRs. It highlights the limitations of conventional GaN DBRs and validates how nanoporous structures can effectively address these challenges. Various fabrication methods, such as metal-organic chemical vapor deposition, molecular beam epitaxy, electrochemical etching, and photoelectrochemical etching, are analyzed in detail along with their challenges. The article focuses on the effects of electrolytes, applied voltage, doping density, and etching parameters on pore size and porous morphology. The review further investigates the impact of nanoporous structures on the reflectivity and bandwidth of the DBRs, supported by a comparative analysis with traditional DBRs. Current and emerging applications in optical filters, photonic devices, light-emitting diodes, and lasers are explored. The discussion on the potential of nanoporous GaN DBRs to advance the future of photonic devices is included. This review aims to serve as a valuable resource for researchers and engineers in the field, providing insights into the advancements and potential of nanoporous GaN DBRs in optical device technology.

We study in detail the form of the orbits in integrable generalized Hénon-Heiles systems with Hamiltonians of the form $H=\frac{1}{2}({\dot{x}}^{2}+A{x}^{2}+{\dot{y}}^{2}+B{y}^{2})+\epsilon (x{y}^{2}+\alpha {x}^{3}).$ In particular, we focus on the invariant curves on Poincaré surfaces of section (y = 0) and the corresponding orbits on the x − y plane. We provide a detailed analysis of the transition from bounded to escaping orbits in each integrable system case, highlighting the mechanism behind the escape to infinity. Then, we investigate the form of the non-escaping orbits, conducting a comparative analysis across various integrable cases and physical parameters.

Additive manufacturing (AM) possesses the capacity to transform production and materials engineering by facilitating the amalgamation of dissimilar metals to create components that are lightweight, durable, and economical. This study provides a thorough analysis of the status of AM for dissimilar materials, including advantages, limitations, and diverse industrial applications. Identified key problems encompass material incompatibility, thermal stress impacts, and the development of brittle intermetallic compounds. A variety of strategies for material integration in AM are examined, including insights into material classifications, mechanical properties, industrial uses, and persistent problems. The incorporation of artificial intelligence (AI) and machine learning (ML) in augmenting the functionalities of AM is examined. This integration seeks to enhance industrial applications, forecast material behaviours, and promote the creation of innovative material combinations while addressing existing obstacles related to AI and ML integration. This paper provides a comprehensive examination of the opportunities and problems associated with the AM of heterogeneous materials, acting as a reference for future research and development initiatives to maximize the potential of this disruptive technology.

Despite their many advantages, the widespread application of magnesium (Mg) alloys is hindered by their high corrosion rates and poor ductility and formability. One effective method for enhancing both the corrosion resistance and mechanical properties, such as ductility, of Mg alloys is through alloying with Rare Earth (RE) elements. These elements have recently garnered significant attention due to their beneficial properties, including an electrode potential similar to that of Mg and their capacity to refine grain size, which contributes to reduced corrosion rates and enhanced alloy strength. This paper explores the common forms of Mg corrosion and elucidates the mechanisms by which RE elements improve corrosion resistance and mechanical behavior in Mg-RE alloys. It also provides a detailed analysis of how each RE element alters the corrosion behavior of Mg-based alloys. By integrating RE elements, it is possible to control corrosion and improve mechanical properties through mechanisms like solid solution strengthening, grain refinement, and the formation and distribution of secondary phases.

Heat transfer enhancement has become an important research area to improve the efficiency of thermal systems. This chronological review focuses on approaches for heat transfer enhancement by incorporating inputs into strategies. An in-depth review has been carried out with inserts such as twisted tapes, turbulators, vortex generators, dimple surfaces and porous materials to improve heat transfer in a variety of applications like heat exchangers, renewable energy devices, automotive systems and electronic cooling systems. A comprehensive literature review across several decades was conducted to examine the progress in improving heat transfer efficiency. Various numerical, analytical and experimental methods used in the study were examined to correct the processes and effects of different insert designs. The study includes various insert geometries, structures and materials providing a detailed analysis of the state-of-the-art in heat transfer enhancement. The review highlights key findings from studies of various inputs and their effects on heat transfer enhancement. It provides insight into efficiency metrics such as the Nusselt number, coefficient of heat transfer and pressure drop associated with each insertion method. In addition, the chronological presentation allows trends and improvements to be identified in insert-based heat transfer enhancement over the years. The results in various applications show the effectiveness of certain insert geometries and configurations in improving heat transfer performance. This chronological analysis provides a comprehensive overview of the progress in heat transfer enhancement through the use of different approaches. Knowledge gathered from various studies demonstrates the potential of insert-based methods to significantly improve the thermal conductivity of various thermal systems. Insights gained from this study can guide future research efforts, contributing to efficient and sustainable heat transfer technologies that have been developed. The conclusion highlights the importance of continued research in this area to address the growing challenges of thermal management and energy efficiency.

Two-dimensional (2D) Boron Carbon Nitride (BCN) has recently gained significant attention as a convoluted ternary system owing to its remarkable capability to exhibit a wide range of finely tunable physical, chemical, optical, and electrical properties. In this review, we discuss a variety of stable structure forms of BCN nanosheets. In addition, this review provides recent approaches for synthesizing BCN nanostructures, and properties of BCN derivatives. BCN is a promising material for sustainable energy and energy storage devices. Since BCN application is a challenge in the field of energy, we present potential applications of BCN in the field of energy including supercapacitors and batteries, wastewater treatment, electrochemical sensing, and gas adsorption.

The widespread application of synthetic dyes across industries poses significant environmental problems, particularly concerning with degradation of water quality. Concerning the possible solutions, copper oxide (CuO) considered as a feasible candidate. CuO a p-type heterogeneous semiconductor with a bandgap of 1.2–2.71 eV, It is a reasonable choice and widely studied photocatalyst for addressing such challenges. The functionality of CuO deteriorated, when the wavelength exceeded the UV–visible region. In this manner difficulties associated with reproducibility and reusability, as well as rapid electron–hole recombination, prevent the widespread application of this technology. In an attempt to eliminate this defect, researchers have been investigating strategies to activate CuO under visible light, with one promising approach being carbon nanomaterials such as graphene to form carbon-CuO composites. The unique properties of graphene, i.e., its higher surface area and excellent electron mobility, make it a remarkable candidate for the enhancement of CuO photoactivity. This study highlighted the recent progress in the synthesis of graphene-based CuO photocatalysts, with the main characteristic of extending the light absorption capacity of CuO into the visible spectrum. It reveals achievements in material innovations and applications, with a focus on photocatalytic. It has been observed from the documented studies, catalysis is considered as next generation emerging field for the researcher.

While multivariate chaotic systems inherently exhibit cross-variable dynamical coupling, existing modeling approaches often neglect the distinct chaotic properties embedded within individual variables. To address this critical limitation, we propose a Multi-scale Stacked Kernel Temporal Convolutional Network (MSK-TCN) that systematically decouples variable-specific chaotic dynamics from multivariate interactions. The framework introduces three core innovations: (1) To solve the modeling difficulties caused by the different embedding dimensions of the multivariate phase space reconstruction, Channel-independent Embedding is designed to unify the embedding dimensions of the different variables and to expand the receptive fields of the model; (2) To be able to more fully and accurately inscribe the chaotic attractor of each variable in the phase space, Stacked Kernel (SK) is constructed and Multi-scale SK (MSK) is used to inscribe the chaotic attractor locally and globally and capture the chaotic properties of each variable; (3) An Independent Mixer is proposed to further extract the chaotic properties of each variable at multiple scales through variable independence and to capture the correlation between variables at multiple scales through feature independence. The single-step and multi-step prediction experiments conducted on the Lorenz, Rossler, and Power datasets show that the MSK-TCN model exhibits lower RMSE and MAE, as well as a higher R2. These indicators fully demonstrate that the proposed model has a significant advantage in prediction accuracy and is significantly superior to eight mainstream comparison models such as ModernTCN and DLinear through the generalized likelihood ratio test. This work provides a new paradigm for variable independent and multi-scale stacked convolutional networks to predict multivariate chaotic time series.

This paper presents a cavity model analysis of a novel penta-band MIMO antenna that is compact in size (measuring 76×33 mm2) and utilizes three PIN diodes for reconfigurability. This antenna resonates at 2.1, 3, 3.5, 4, and 4.2 GHz in different states (state-000, state-011, state-111, state-100, and state-000, respectively) and offers a fractional bandwidth of 4.95% (simulated), 5.5% (measured) and
 4.92% (theoretical) in state-000, 3.09% (measured), 2.8% (simulated) and 2.3% (theoretical) at lower frequency (2.1 GHz), and 2.12% (simulated), 2% (measured) and 2.4% (theoretical) at higher frequency (4.2 GHz) in state-100, 12.5% (simulated), 12% (measured) and 11.6% (theoretical) in state-011 and 4.6% (simulated), 4.7% (measured) and 4.4% (theoretical) in state-111. Furthermore, the
 antenna exhibits impressive performance with a peak gain and isolation of 3.6 dB and 32.2 dB at 4 GHz and 3.5 GHz, respectively. The proposed design also maintains low specific absorption rate (SAR) and envelope correlation coefficient (ECC) values, with SAR and ECC values less than 1 W/kg and 0.01, respectively. Moreover, a lumped element RLC equivalent circuit for the intended antenna is proposed using cavity model circuit theory. The proposed circuit produces theoretical reflection coefficients of the proposed antenna and has been validated through comparison with both simulated and measured results.

Dual-parameter sensors are highly competitive and commercially valuable in industrial, medical, and biochemical fields. A two-parameter surface plasmon resonance (SPR) sensor with an ultra-wide measuring range is proposed, which can measure both refractive index (RI) and temperature (T). The sensor structure is a right-angle side-polished type, with Ag+Au deposited on one side-polished surface for RI measurement and Ag+Au+polydimethylsiloxane (PDMS) on the other side-polished surface for T measurement. The combination of the right-angle side polishing structure and the gold-silver composite film enables the sensor to have an extremely wide RI and T detection range. The wide measurement range not only meets the common liquid RI detection, but also enables the detection of substances with RI below 1.3333, such as halogenated ethers, fluorinated organic compounds and aerogels. The right-angle side polishing enables the SPR to be excited at a wider range of incidence angles, enabling the sensor to measure in a wider parameter range. The gold-silver composite film has the ability to widen the wavelength range and enhance the local electric field intensity, so that the sensor can detect substances with low RI. Gold film also prevents the silver layer from being degraded by the environment, increasing the service life of the sensor. The calculation results show that the sensor achieves a maximum RI sensitivity of 17900 nm/RIU (RI measurement range 1.20~1.42) and a maximum T sensitivity of 12.8 nm/℃ (T measurement range -10 ℃~200 ℃), and do not interfere with each other, a perfect solution to the crosstalk problem. In RI and T measurement, the sensor has a wide measuring range and good sensitivity, which makes it have a good prospect in environmental detection, biomedical and aerospace fields.

Transparent and semi-transparent photovoltaics enable seamless integration of solar panels into building elements, thereby advancing the adoption of renewable energy utilization in the built environment without compromising design or functionality. Metamaterials can absorb a broad spectrum of light in the mid-infrared range while remaining transparent in the visible spectrum (400-800nm). This paper introduces a novel optically transparent perfect absorber (OTPA) utilizing an indium tin oxide (ITO) substrate as its foundation. The dual functionality of ITO, exhibiting strong absorption in the infrared while remaining transparent in the visible range, makes it an ideal candidate for integration into transparent solar cells (TSCs). The proposed metamaterial-based solar absorber comprises four identical square patches separated from the ITO ground plane by a Zinc Sulphide (ZnS) dielectric layer. The proposed structure employs geometrically optimized square patches to achieve broadband absorption, where nanoscale design modifications play a critical role in enhancing impedance matching and tuning resonant modes for maximum efficiency. The proposed ZnS/ITO-based Solar thermophotovoltaic (STPV) design achieves over 98% absorption in the mid-infrared spectrum (3000-14000 nm) while maintaining an average optical transmittance above 70% with a peak transmittance of 87% in the visible spectrum. Simulation results confirm broadband absorption under both transverse electric (TE) and transverse magnetic (TM) polarizations, maintaining high performance for incident angles up to 70° and polarization angles up to 90°. Infrared absorption efficiency, evaluated using the Fabry-Perot model, reveals a strong agreement with simulation results. The proposed ultrathin transparent absorber is of great potential for applications in building integrated photovoltaics (BIPV), radiative cooling and infrared imaging.

Based on density functional perturbation theory (DFPT), the phonon dispersion of monolayer MoSe2, monolayer WSe2, and MoSe2/WSe2 heterostructures under biaxial strain were systematically calculated and analyzed, and the maximum strain tolerance of these three structures was investigated. The results reveal that monolayer MoSe₂ and WSe₂ can sustain biaxial tensile strains reaching 18%, while the MoSe₂/WSe₂ heterostructure can sustain biaxial tensile strains reaching 16%. Furthermore, the effects of biaxial strain on the entropy, enthalpy, free energy, and heat capacity of the three structures were computed. At a fixed temperature, as the applied strain increases, both the entropy and enthalpy of the system exhibit a significant upward trend, whereas the free energy and heat capacity decrease. Notably, temperature has a negligible impact on the heat capacity beyond 300 K. When the thermal performance curves deviate from their regular patterns with increasing strain, the structure becomes damaged and loses stability. These findings provide critical insights into the strain-dependent thermal properties and mechanical limits of monolayer and heterostructure systems.

We present an experimental and theoretical study of the transport dynamics of the motion of a magnetized ball under the influence of a periodically alternating external magnetic field. The coupling between the driving field and the particle magnetic moment creates an energy reservoir that the particle uses to self-propel, while the oscillation frequency of the field, governs the rich variety of the particle patterns of motion. For each maximum amplitude of the external magnetic field considered in this study, the particle's motility dynamics exhibits different transport properties. These range from low-persistent motion at small frequencies, to a highly persistent regime at intermediate frequencies. Through theoretical analysis of the single-particle trajectories, we demonstrate control of the transport properties of the particle by tuning the frequency of the external driving field. We elucidate that for frequencies close to the characteristic frequency defined by the coupling between the ball's magnetic moment and the driving oscillating field, persistent motion emerges as consequence of the resonant dynamics. Furthermore, we develop a stochastic model that incorporates the nonlinear behavior of the angle between the ball's magnetic moment and the time-varying external magnetic field. The model generates trajectories that qualitative agree with those observed in the experiment.

The nuclear structure in the even–even ^160-180Er chain of isotopes is investigated by means of a mean-field-derived IBM-1 Hamiltonian with an intrinsic triaxial deformation derived from fermionic proxy-SU(3) irreducible representations (irreps). Energy levels and B(E2) transition strengths are calculated and compared to experimental data, where available. It is shown that the inclusion of an intrinsic triaxial deformation, stemming from the proxy-SU(3) irreps, leads to a significantly improved agreement between theoretical predictions and experimental data, compared to the axially symmetric case. The results are also compared to recent triaxial projected shell model (TPSM) and Monte Carlo Shell Model (MCSM) predictions, showing an overall good agreement, further pointing toward the preponderance of triaxiality throughout the nuclear chart.

Transparent and semi-transparent photovoltaics enable seamless integration of solar panels into building elements, thereby advancing the adoption of renewable energy utilization in the built environment without compromising design or functionality. Metamaterials can absorb a broad spectrum of light in the mid-infrared range while remaining transparent in the visible spectrum (400-800nm). This paper introduces a novel optically transparent perfect absorber (OTPA) utilizing an indium tin oxide (ITO) substrate as its foundation. The dual functionality of ITO, exhibiting strong absorption in the infrared while remaining transparent in the visible range, makes it an ideal candidate for integration into transparent solar cells (TSCs). The proposed metamaterial-based solar absorber comprises four identical square patches separated from the ITO ground plane by a Zinc Sulphide (ZnS) dielectric layer. The proposed structure employs geometrically optimized square patches to achieve broadband absorption, where nanoscale design modifications play a critical role in enhancing impedance matching and tuning resonant modes for maximum efficiency. The proposed ZnS/ITO-based Solar thermophotovoltaic (STPV) design achieves over 98% absorption in the mid-infrared spectrum (3000-14000 nm) while maintaining an average optical transmittance above 70% with a peak transmittance of 87% in the visible spectrum. Simulation results confirm broadband absorption under both transverse electric (TE) and transverse magnetic (TM) polarizations, maintaining high performance for incident angles up to 70° and polarization angles up to 90°. Infrared absorption efficiency, evaluated using the Fabry-Perot model, reveals a strong agreement with simulation results. The proposed ultrathin transparent absorber is of great potential for applications in building integrated photovoltaics (BIPV), radiative cooling and infrared imaging.

Fluorine-based plasma etching of Al2O3 causes oxygen vacancy and aluminum bond modifications, which affect the electrical properties of the thin film, leading to increased leakage currents and the formation of charge traps that degrade the device reliability. Therefore, in this study, we systematically examined the effects of CF₄ plasma etching on the structural, optical, and electrical properties of Al2O3 thin films, focusing on defect dynamics during processing. X-ray photoelectron spectroscopy analysis demonstrated that Al-O to Al-F bond conversion occurred during plasma etching, resulting in modified oxygen vacancy concentrations. Chemical modifications induced changes in the optical bandgap and work function with increasing radiofrequency bias power, indicating a change in the electronic band structure. Dielectric measurements indicated reduction in dielectric constant due to Al-F bond formation. These results elucidate the relationship between plasma-induced defects, including both defect generation and atomic substitution by plasma, contributing to the development of high-quality Al₂O₃ thin films for electronic applications in the future.

Bateman pulses are defined, and their properties explored in two simple examples. We consider a one-parameter pulse of the Bateman form, and calculate its energy, momentum, angular momentum and chiral content. A comparison of the Bateman pulse is made with two self-dual pulses having similar properties. The one-parameter pulse is shown transformed to its zero-momentum frame. We also discuss two-parameter pulses of the Bateman type. Field line linkage is considered, and shown to not be restricted to Bateman pulses.

In recent years, deep learning has been successfully applied to the reconstruction of speckle images formed through scattering media. However, most research on imaging through scattering media has mainly focused on reconstructing images of a single object, where the object's information can be extracted from a single speckle using convolutional neural networks.
Reconstructing images of multiple objects from a single speckle is more important and challenging, as the information of the objects becomes highly mixed during the light propagation process. Moreover, in the speckle imaging process, most neural networks are trained to predict pixel-by-pixel, treating each pixel of the image independently. This can lead to a lack of spatial continuity in the final result. To achieve better performance, the network should not only focus on the class features of each pixel value but also consider enhancing the visual appearance of the reconstructed image.
In this paper, a CNN and GAN-based network model is designed for speckle image reconstruction. The model consists of an encoder and two decoders. A network called DCGAN (Double_CNN_GAN) is proposed to reconstruct speckle patterns. By using DCGAN, we achieve high-fidelity simultaneous reconstruction of two different binary or grayscale object images located behind the scattering medium. Additionally, the influence of the distance between the two objects on the reconstruction quality is explored. Therefore, the study of methods for reconstructing the speckle images of two adjacent objects is of significant theoretical and practical importance.

We studied free electron collision-induced fragmentation of HFO1234ze(E) (C₃H₂F₄). The motivation of the present study is to assess the possibility of using this gas in resistive plate chamber detectors and for the interest in its electron-induced decomposition. Two electron-collision setups, which complement each other, are used. Additionally, the interpretation of the data is supported by quantum chemical calculations. We provide absolute partial cross sections both for the dissociative electron attachment and for the positive ionization. We also report the ionization energy of HFO1234ze(E) and the appearance energies of selected fragments. A surprising finding of the current study is that the dominant anionic fragment from the dissociative electron attachment is the bifluoride anion [F-H-F]⁻.

The ballistic launch of cold atoms is crucial to a range of advanced investigations, serving as a highly precise source for timekeeping, gravimetry, and fundamental studies in quantum technologies. A detailed understanding of atomic dynamics during these launches is essential for furthering research in these fields. In this study, we investigate the ballistic launch of cold 133Cs atoms and observe a remarkable behavior in the launched atomic cloud. Following the launch, an abrupt change in frequency detuning caused the cold atomic cloud to segment into two parts with distinct velocities. Our work details and characterizes the effect of segmentation on the thermal and velocity properties of the atomic cloud. This non-adiabatic segmentation phenomenon has significant implications for improving the precision of quantum devices that rely on the precise control of free-flying atomic clouds.

The crosstalk effect in piezoelectric micromachined ultrasound transducer (PMUT) arrays is a significant challenge that negatively impacts device performance. To address this issue, this study utilizes the excellent sound isolation properties of sonic crystals by designing a multi-resonant cavity sonic crystal structure, which is integrated into the PMUT chip. The designed PMUT features a resonant cavity with a radius of 200 μm and a resonant frequency of 785 kHz. Furthermore, this new structure has been validated through finite element simulations and has been compared with traditional PMUT and isolation pillar PMUT. The results show that, compared to traditional PMUTs, the single-period and two-period sonic crystal PMUTs achieve a significant reduction in crosstalk—by 45.9% and 55.2%, respectively—reaching crosstalk coefficients as low as 0.50% and 0.30%. And the proposed sonic crystal strategy outperforms the existing isolation pillar approach. Additionally, the study investigates the crosstalk formation mechanism in PMUTs with convex isolation structures, highlighting sound diffraction as a key factor contributing to this phenomenon.

The Quantum Natural Gradient (QNG) method enhances optimization in variational quantum algorithms (VQAs) by incorporating geometric insights from the quantum state space through the Fubini-Study metric. In this work, we extend QNG by introducing higher-order integrators and geodesic corrections using the Riemannian Euler update rule and geodesic equations, deriving an updated rule for the Quantum Natural Gradient with Geodesic Correction (QNGGC). We also develop an efficient method for computing the Christoffel symbols necessary for these corrections, leveraging the parameter-shift rule to enable direct measurement from quantum circuits. Through theoretical analysis and practical examples, we demonstrate that QNGGC significantly improves convergence rates over standard QNG, highlighting the benefits of integrating geodesic corrections into quantum optimization processes. Our approach paves the way for more efficient quantum algorithms, leveraging the advantages of geometric methods.