The electron transport layer (ETL) plays a critical role in facilitating charge transport and influencing the overall performance of perovskite solar cells (PSCs). Titanium dioxide (TiO₂), owing to its favorable band alignment and chemical stability, remains the most commonly employed ETL. However, it suffers from limitations such as low electron mobility, high charge recombination, and poor UV stability. In this study, we enhance the optoelectronic properties of mesoporous TiO₂ by surface modification with cadmium sulfide (CdS) quantum dots via the successive ionic layer adsorption and reaction (SILAR) method. Additionally, we investigate the impact of different annealing temperatures (200, 300, 400, 450, and 500 °C) on the morphology and photovoltaic performance of the fabricated PSCs. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses revealed that increasing CdS deposition cycles led to more compact perovskite layers with larger grain sizes and highly crystalline perovskite films. Optical absorption (UV–Vis) and photoluminescence (PL) spectra exhibited a redshift in the absorption edge and diminished emission intensity, indicating improved crystallinity and suppressed radiative recombination. The photovoltaic parameters measurements showed that after five cycles of CdS SILAR and annealing at 400 °C, the device achieved a power conversion efficiency (PCE) of 5.88%, significantly higher than the 4.43% obtained for the pristine TiO₂-based device annealed at 500 °C. This improvement is attributed to better charge extraction, reduced interfacial recombination, and enhanced light absorption. The study demonstrates that CdS sensitization effectively passivates surface defects in TiO₂ and enables efficient charge transport. Furthermore, annealing at a moderate temperature of 400 °C proved optimal for balancing morphology, and interfacial properties. These findings highlight the synergistic effect of CdS modification and thermal optimization, providing a promising strategy for improving the efficiency and stability of PSCs.
In this study, the effect of uniaxial strain on the structural and electronic transport properties of pristine borophene and three of its hydrogenated configurations is investigated using density functional theory (DFT) calculations. Borophene is a two-dimensional structure composed of boron atoms that, due to lattice mismatch with the substrate during synthesis, may be subjected to small degrees of strain. Moreover, hydrogenation can increase its structural stability. Therefore, the simultaneous effects of small uniaxial tensile and compressive strains and hydrogenation on the band structure, partial density of electronic states, and current–voltage (I–V) characteristics of borophene are studied. The results indicate that the transport properties of both pristine and hydrogenated borophene display directional dependence, and this anisotropic behavior can be modified by applying strain. Analysis of the I–V characteristics at bias voltages below 1 V indicates that strain affects the degree of current anisotropy. For pristine borophene, the current anisotropy ratio at a bias voltage of 1 V is found to be 0.74, which varies significantly upon hydrogenation, leading to isotropic current behavior in one of the considered configurations. Additionally, comparison of the Poisson ratios along the armchair and zigzag directions reveals that hydrogenation softens the hydrogenated structures along the armchair direction compared with pristine borophene. The tunability of the I–V behavior under small strains highlights the high potential of these structures for applications in next-generation electronic devices.
This study examines the interaction of a coherent Gaussian beam with a separable two-dimensional optical structure, going beyond the plane-wave approximation, for practical applications that utilize the Gaussian beam profiles from lasers. We develop a more realistic framework to describe the optical beam diffraction, which better matches experimental conditions. Our results demonstrate that this process forms structured light beams and preserves their transverse shape and structure over longer propagation distances. This shape-invariance property renders them particularly valuable for precision-oriented and controlled applications in science and technology. The effect of the incident beam wavelength on the diffraction pattern of a binary radial phase grating is investigated. The analyses reveal that the intensity distribution exhibits azimuthal symmetry, and the number of the principal lobes in both the intensity and phase profiles of the diffracted field is twice the number of sectors in the binary radial phase grating. A comprehensive and practical diffraction framework, based on the Fresnel–Kirchhoff integral, is formulated in polar coordinates to describe Gaussian beam interaction with binary radial phase gratings. Based on this framework, the closed-form analytical expressions are derived for the resulting complex optical field.
In this research, we consider Composite Higgs Models with a relatively small global symmetry-breaking scale, f, in the strong coupling sector, where the Higgs boson emerges as a pseudo-Nambu-Goldstone boson. The model also includes a singlet scalar resonance, the sigma particle (σ), which mixes with the Higgs. Using an effective chiral Lagrangian, the structure of the vacuum minima of the theory is analyzed. It is shown that, in the absence of σ, achieving values of f above 1 TeV requires a small amount of fine-tuning to be consistent with experimental constraints. However, mixing with this light scalar particle resolves this tension and allows for a lower value of f. Subsequently, we impose up-to-date experimental constraints based on combined LHC Run-2 fits to the Higgs couplings to gauge bosons and the top quark. By also applying limits from searches for exotic Higgs decays, the parameter space of the model is quantitatively determined, and viable benchmark points are extracted. Furthermore, an alternative scenario based on the CDF results is investigated to illustrate the model's sensitivity to independent collider data. The analyses demonstrate that the presence of the light scalar σ can effectively alleviate constraints arising from the electroweak precision parameters S and T, as well as from deviations in the Higgs couplings.
In this study, the effect of argon plasma jet irradiation on two-dimensional polymeric opals and its role in engineering inverse opal TiO₂ structures was investigated. Two-dimensional opals were fabricated from poly(methyl methacrylate) (PMMA) microspheres via a self-assembly method at the air-liquid interface and subsequently exposed to atmospheric-pressure argon plasma. The influence of the plasma–sample distance and irradiation time on the morphological evolution of the structures was systematically examined. The TiO₂ precursor was infiltrated into the opal templates before and after plasma treatment, and after removal of the polymer mask, inverse opal TiO₂ structures were obtained. Field-emission scanning electron microscopy (FESEM) revealed that at a 4 mm distance, increasing irradiation time from 3 to 8 minutes caused a continuous reduction in microsphere diameter and gradual deterioration of hexagonal order, whereas at a distance of 6 mm, changes were less pronounced, with only a slight reduction in particle size. Analysis of the final TiO₂ structures showed that plasma-treated templates produced smaller pores and thicker walls, leading to a higher TiO₂ filling fraction. However, excessive irradiation induced lattice disorder and wall damage. These results demonstrate that careful adjustment of plasma parameters—distance and exposure time—provides an effective tool for controlling the morphology and structure of inverse opals. The resulting nanostructures, with tunable optical and surface properties, are promising for photonic devices, biosensors, chemical sensors, chromatography, biomedical systems, solar cells, and photocatalytic applications.
In this work, the diffraction of a Gaussian beam by a radial phase grating with a sinusoidal profile is investigated theoretically. The results unambiguously confirm that this process leads to the generation of radial carpet beams. It is found that reducing the beam-waist radius of the incident beam affects the intensity of the main lobe, while simultaneously confining the side-lobe intensity along the radial direction. Moreover, the wavelength of the beam incident on the radial phase grating with a sinusoidal profile plays a decisive role in shaping the diffraction pattern. The analysis further reveals that even very small variations in the number of grating sectors significantly alter the phase arrangement, although the intensity pattern remains nearly stable. The self-healing property of radial carpet beams is found to depend on both the number of grating sectors and the size of the obstructed region. Specifically, increasing the number of sectors and decreasing the obstruction size reduces the beam’s self-healing distance.
In this experimental study, the trapping of the translational motion of a supersonic beam of polar ammonia (NH₃) molecules in the rotational ground state (J = 0) of the para species using a microwave field is demonstrated. A cold beam of ammonia molecules seeded in argon gas passes through a superconducting Fabry–Perot resonator, where a standing-wave microwave field in the TEM₀₂ transverse mode is generated near the molecular transition frequency of 23.7 GHz. The mixed gas trapped at the center of the vacuum chamber is cooled to a temperature of 2.3 mK and ionized using the Resonance-Enhanced Multiphoton Ionization (REMPI) technique with the 16101 cm⁻¹ line of a Rhodamine dye laser. The emission spectrum is then recorded with the microwave field switched on and off. The change in the angular momentum of the polar ammonia molecule without the required excitation energy being supplied indicates a quantum tunneling effect induced by the Stark shift. This article presents the first report of the experimental results of this research conducted at the University of British Columbia.
An attempt has been made to modify the original version of the Aage Winther 1995 (AW95) potential by adding a positive Gaussian part as VRexp(-br2) to investigate the effect of the repulsive core on the sub-barrier fusion cross sections. In order to achieve this goal, we select and evaluate 6 heavy ion fusion reactions with 392≤Z1 Z2≤784 (including 58Ni+54Fe, 58Ni+58Ni, 64Ni+64Ni, 16O+208Pb, 28Si+64Ni, 28Si+100Mo). The obtained results reveal that the original version of the AW potential supplemented with Gaussian positive part successfully reproduces the experimental fusion excitation data for various considered systems.
In this study, the radioactivity concentration in the soil and sediments of the Galougah River on the southern side of the Miankaleh Wetland in northern Iran, which originates from the northern heights of the Alborz Mountains, as well as the bed wetland sediments of the estuary of that river was studied. The mean specific activities of 226Ra, 232Th, 40K, and 137Cs in the sediments of the Galougah River respectively were 32.12, 32.47, 339.81, and 2.53 Bq/kg, in the soil along the river respectively were 34.20, 38.28, 505.94, and 6.89 Bq/kg, and in the wetland bed sediments near the mouth of the Galougah River respectively were 20.88, 21.22, 287.90, and 2.75 Bq/kg obtained. The average radioactivity concentration in the river sediments was lower than that of the surrounding soil, indicating that radioactive salts were washed away and transported to downstream areas by the river water flow. The high concentration of 40K in the downstream part of the river could be due to contamination from potassium fertilizers used for agricultural purposes in that area. The distribution pattern of 226Ra in the Miankaleh Wetland near the outlet of the Galougah River indicates the rapid deposition of this radionuclide immediately after leaving the river mouth, which settles in sandy-clay sediments. A similar distribution pattern was obtained for 232Th and 40K in the wetland, indicating a similar influence on the diffusion of these radionuclides from the water currents of the wetland, as well as a similar absorption of thorium and potassium salts by the sediments. The distribution pattern of 137Cs in the wetland indicates that this radionuclide is deposited in far from the river outlet in the calm area of the wetland, which is due to the high mobility of 137Cs, which causes it to be transported to distant locations by water flow.
In this paper, we examine the theory of quantum electrodynamics with massless fermions in two dimensions (the Schwinger model). First, we derive the effective action of the photon by integrating out the fermionic degrees of freedom. Then, using this effective action and the scattering-matrix approach, we prove that the amplitudes of all diagrams contributing to the photon polarization tensor at two- and three-loop levels vanish. Next, we demonstrate that all other quantum corrections arising from higher-order perturbations also vanish. We therefore conclude, within perturbation theory, that the photon polarization tensor, and consequently the Schwinger mass, are one-loop exact.
In this paper, we analyze the shadow of a black hole immersed in a dynamic background reflecting the expansion of the universe due to the presence of dark energy. Using a time-dependent metric (the dynamic Kottler metric), we obtain the null (lightlike) geodesics of spacetime and calculate the effective potential for light rays. Our results show that the expansion of the universe causes the radius of the photon sphere, and consequently the black hole shadow, to decrease gradually over time. This phenomenon can be a way to determine cosmological parameters.
Heteroclinic cycles provide a powerful model for describing transient and flexible sequential state transitions in dynamical systems, with applications ranging from neural networks and genetic circuits to chemical oscillators and lasers. They provide a framework for representing metastable states and analyzing information dynamics. In this study, we consider a three-population Kuramoto-type phase oscillator network in the “near-cluster” regime and, using a reduction onto the Ott–Antonsen manifold, derive a Lotka–Volterra–type competitive system that describes its reduced dynamics. This mapping enables us to obtain explicit necessary and sufficient conditions for the existence of a heteroclinic cycle with a prescribed orientation between the boundary equilibria. These conditions depend directly on the effective coupling coefficients, locked phase differences, and the phase-lag parameter. To assess their validity, the entire space of locked phase differences is sampled and the regions supporting a heteroclinic cycle are identified. Phase-space simulations further confirm the emergence of heteroclinic cycle dynamics. Moreover, the results show that, within a limited range of parameters, increasing the phase-lag constant reduces the size of the phase-difference regions that support the heteroclinic cycle. Taken together, these findings provide testable criteria for designing controllable networks with flexible transient dynamics and establish a clear link between physical oscillator models and neural function, multi-stage rhythm generation in biological systems, and brain-inspired applications in artificial intelligence.
The dynamics of a hybrid system consisting of three magnetic spheres embedded in a microwave cavity are investigated, where each sphere is subjected to static and time-varying magnetic fields. The results show that, in a symmetric configuration with identical spheres, the cavity-mediated coupling leads to the formation of bright and dark modes. Applying periodic drives enables coherent and dynamic control over the hybrid magnon–photon states. Through Floquet engineering, the coupling between the main and drive-induced sideband modes can be precisely and reversibly tuned by adjusting the drive frequency and amplitude, providing a framework for dynamic control of hybrid states in quantum systems.
In this paper, we report the results of searching the TESS data from spectroscopic binary systems discovered by the Gaia telescope. The TESS telescope with a high photometric resolution generaly observes bright and nearby stars with a cadence in the order of some minutes to half an hour. In this research, for 161 binary systems discovered through spectroscopic observations by the Gaia space telescope, we extract their photometric data taken by the TESS telescope to find any periodic either eclipse or self-lensing signal. Our aim was to determine the orbital inclination angle and other physical parameters of these systems if such signals are detected in their photometric data. We could not find such systems with photometric and periodic signals with the period exactly matching the orbital period reported by the Gaia telescope. Hence, none of systems are edge-on as seen by the observer. However, for some systems the periods of variations in their light curves are close to the orbital periods reported by the Gaia Telescope (differing by approximately 10 days or slightly more). In future, we aim to study their photometric data taken by other telescopes to resolve the nature of variations in their light curves.
In this research, the thermodynamic properties of the nucleus have been investigated using the temperature-dependent level density parameter. Calculations have been carried out based on the BSC and Ignatyuk models. A well-known limitation of the BCS model is that the gap parameter drops to zero at the critical temperature, which leads to discontinuities and the appearance of singular points in the heat capacity curve. To overcome this problem, the gap parameter in the BCS model has been replaced with an order parameter derived from the generalized Ginzburg-Landau theory, and the resulting improved model was introduced as GBCS. Subsequently, the temperature-dependent level density parameter has been calculated using the GBCS and Ignatiuk models. Finally, by utilizing the temperature-dependent level density parameter, the thermodynamic quantities of the nucleus such as the nuclear level density, entropy, and heat capacity have been obtained using the mentioned models and compared with available experimental data.
One simple combination of particles which captures effect of hydrodynamic interactions consists of two trapped beads, immersed in fluid, each with a single degree of freedom, and fluctuating around its equilibrium positions. Given such a system in the presence of a flat boundary, we consider effect of an external velocity or temperature field on it. The external field drives the two beads system, out of equilibrium. We calculate beads’ auto/cross correlations in the presence of external field, then investigate if these auto/cross correlations can be used to reveal the presence of a possible external field, and its nature. We find that the former question could be answered successfully, while the latter requires additional information or additional degrees of freedom accessible to the observer.
A wide range of fundamental problems in science—including the determination of equilibrium states in physical systems and the training and analysis of neural networks—can be cast as optimization problems. However, the intrinsic complexity of these systems, particularly near critical points and phase transitions, often renders the computation of even approximate solutions highly demanding. Methods originating from statistical physics, especially those developed for the study of disordered and complex systems, have contributed significantly to the development of more efficient computational strategies for such tasks. In this review, we review key concepts and algorithmic approaches inspired by classical and quantum statistical mechanics, with an emphasis on recent theoretical developments and practical applications. Particular attention is devoted to reinforcement-based optimization methods and their role in improving solution quality, as well as the implications of reinforcement mechanisms for noise mitigation in quantum systems. We conclude by outlining several open challenges and promising directions for future research.
Light reflection is one of the main factors that reduces the efficiency of silicon solar cells. In conventional thick silicon cells, anti-reflection structures such as textured surfaces are used, but this method is not effective for new generation thin-film cells with a thickness of approximately 3 μm. In this study, silicon thin-film cells with a single anti-reflection layer (Si₃N₄) and a double anti-reflection layer (MgF₂/Si₃N₄) were simulated using the finite difference time domain (FDTD) numerical method. The results showed that, for the cell with a single-layer coating, the lowest reflection is achieved when the thickness of the Si₃N₄ layer is 62 nm. In the double-layer structure of MgF₂/Si₃N₄, the most optimal thicknesses were 112 and 62 nm, respectively. In addition, the electrical performance of the cell was carried out in two ideal (defect-free) and real (taking into account volumetric and surface defects) states. The electro-optical analysis showed that the presence of defects can reduce the cell efficiency by about 50% compared with the ideal state.
Entanglement is an inherently quantum phenomenon, and particle-particle scattering can generate quantum entanglement depending on the interaction potential between the two particles. The theoretical evaluation of the entanglement generated during particle-particle scattering is carried out using entanglement fidelity. The particle-particle interaction potential is modified in the presence of other particles, such as those in a plasma environment, and under an external electric field induced by a laser. Consequently, quantum entanglement becomes a function of plasma and laser parameters. In this study, a dense two-temperature plasma environment consisting of electrons and ions is considered, which can exhibit either classical or quantum behavior, including quantum diffraction and exchange symmetry, while an external electric field (laser) is also present. The interaction of the laser with plasma particles excites oscillations and modifies the plasma dynamics, all of which can be incorporated into the effective particle-particle interaction potential. Therefore, the effects of plasma parameters, such as temperature and density, as well as laser intensity, on entanglement can be directly analyzed. The results show that low collision energy, low plasma temperature, high particle density (or short Debye length), and specific ranges of laser intensity lead to an enhancement of quantum entanglement. Furthermore, in an electron-ion plasma, the electron temperature plays a much more significant role in entanglement dynamics than the ion temperature.
