The European Physical Journal Plus最新文献

We explore the evolution of the deep inelastic scattering (DIS) entropy, defined as ( S(x,mu ^2) simeq ln [xg(x,mu ^2)]) at small Bjorken variable x, where (mu ) is the observable scale and the gluon distribution (xg(x,mu ^2)) is derived from the Dokshitzer–Gribov–Lipatov–Altarelli–Parisi (DGLAP) evolution equations. We aim to evolve the DIS entropy, which is not directly observable, using a Laplace transform technique. This approach allows us to obtain an analytical solution for the DIS entropy based on known initial gluon distribution functions. We consider both leading-order (LO) and higher-order approximations for the DIS entropy, incorporating the evolved gluon distribution function at the initial scale. The DIS entropy, influenced by purely gluonic emissions, varies with higher-order corrections to the running coupling. By comparing theoretical predictions with charged hadron multiplicity data, we define the evolution. Additionally, we investigate the derivative of the scaling entropy, modeling it as a function of the running coupling, to determine the parameter (lambda ), known as the Pomeron intercept. We find that the values of (lambda (x,mu ^2)) decrease as the order of evolution increases, which is consistent with the Balitsky–Fadin–Kuraev–Lipatov (BFKL) Pomeron in the LO and NLO approximations. This investigation provides insights into the dynamics of quantum chromodynamics (QCD) at high energies.

In this study by using the Newman-Janis algorithm, we obtained a rotating version of the quantum-corrected charged black hole. The quantum correction appeared to reveal the black hole event horizon and ergosphere. Also, we investigated the impact of the various parameters controlling this black hole, such as quantum correction (alpha), electric charge Q, and rotational parameter a, on the system thermodynamics. In addition, the analysis of the heat capacity showed that this quantum correction alters the local stability of our system.

Accurate assessment of rupture risk in cerebral aneurysms, particularly in the middle cerebral artery (MCA), requires detailed hemodynamic analysis of blood flow parameters such as wall shear stress (WSS), oscillatory shear index (OSI), and pressure. However, full-order computational fluid dynamics (CFD) simulations are time-consuming and computationally expensive, limiting their routine clinical use. In this study, we propose a reduced-order modeling framework that combines proper orthogonal decomposition (POD) with a transformer neural network to enable fast and accurate prediction of pulsatile blood flow and key hemodynamic indices within patient-specific aneurysm geometries. Blood flow was modeled using the incompressible Navier–Stokes equations with the non-Newtonian Casson model under laminar conditions, and simulations were performed over three cardiac cycles. The dominant flow features were extracted using POD, and the temporal evolution of modal coefficients was learned using a transformer architecture trained on time-windowed data. Results show that the proposed POD + transformer approach accurately predicts velocity and pressure fields with reconstruction errors below 2% and captures WSS distributions with acceptable fidelity. OSI, due to its inherently complex and oscillatory nature, showed higher prediction errors, highlighting the need for more refined modeling strategies. Overall, the framework provides a promising step toward real-time, data-driven aneurysm hemodynamic analysis, offering significant potential for clinical risk stratification and decision support in neurovascular care.

The generation of robust, metrologically useful quantum states in realistic open systems is contingent on a complex interplay between coherent dynamics, control fields, and environmental decoherence. Through comprehensive numerical simulations of a driven-dissipative cavity QED system, we systematically explore this interplay and uncover a set of non-trivial design principles for engineering practical quantum advantage. Our central finding reveals a critical trade-off between a state’s theoretical complexity and its operational resilience: we consistently demonstrate that the simpler entanglement structure generated by One-Axis Twisting (OAT) is significantly more robust than the more complex, yet fragile, states produced by Two-Axis Twisting. Furthermore, we establish that physical effects typically considered detrimental can be harnessed as protocol-dependent stabilization resources. Strong optical nonlinearities can create protected manifolds that shield the OAT state from decoherence, while strong counter-rotating interactions–a signature of the ultrastrong coupling regime–can actively stiffen the quantum state against metrologically harmful phase-space rotations. These results culminate in a revised design paradigm for quantum technologies: achieving practical quantum advantage necessitates a holistic co-design of the initial entangled state, the control protocol, and the intrinsic physical characteristics of the platform itself.

In this paper, we explore the dynamics, thermodynamics, and observational features of the Bardeen–Kiselev black hole in AdS spacetime, motivated by the need to resolve curvature singularities and incorporate the influence of dark energy in strong gravity regimes. By coupling nonlinear electrodynamics with a quintessence field, the Bardeen–Kiselev–AdS solution provides a physically regular and rich framework to study modified black hole behavior. We first investigate the Hawking evaporation process and show that magnetic monopole charge induces a repulsive core that halts complete evaporation, resulting in a stable remnant which is significant deviation from traditional singular black hole models. In contrast, the Kiselev–AdS black hole without magnetic charge undergoes total mass loss, illustrating the crucial role of nonlinear electrodynamic effects. Next, we analyze the evolution of scalar perturbations and find that increasing the quintessence parameter enhances wave dissipation, while higher magnetic charge improves perturbative stability through deeper effective potentials. To further understand quantum effects, we compute rigorous bounds on the greybody factors using the Visser–Boonserm method and demonstrate that quintessence suppresses radiation transmission, whereas magnetic charge amplifies it, modifying the observable Hawking spectrum. Additionally, we examine the black hole shadow and find that quintessence shrinks the apparent shadow size, while magnetic charge enlarges it due to modifications in the photon sphere geometry. Lastly, employing the Novikov–Thorne model, we simulate the accretion disk images and show how parameters like q, c, and observer inclination (theta) impact the disk s shape, and relativistic lensing features.

This study investigates the heat and mass transfer characteristics of Marangoni convection in a Casson nanofluid over an infinite disk, incorporating Stefan blowing and activation energy effects. The analysis accounts for the influence of a binary chemical reaction, frictional heating, Joule heating, and a magnetic field. Flow dynamics are driven by surface tension gradients due to variations in heat and nanoparticle concentration, with slip effects at the disk surface also considered. The boundary layer partial differential equations are reduced to ordinary differential equations via Von Kármán similarity transformations and solved using the shooting method coupled with the fourth-order Runge–Kutta technique. Further, a multivariate quadratic regression model for Nusselt number and Sherwood number is also proposed. Key parameters influencing the Nusselt number, thermal energy distribution, Sherwood number, nanoparticle concentration, and velocity profiles are systematically analyzed. The main finding of the manuscript is that the temperature reduces as the Stefan blowing, Casson fluid parameter, and thermal slip parameter increase. However, it rises with an increase in the thermophoresis number and the Eckert number, reflecting the influence of these parameters on the system’s thermal dynamics.

The present study investigates the flow dynamics of a two-fluid model based on KL-Newtonian fluids mimicking the blood flow through microvessels. The model distinguishes between the central region of the vessel occupied with the red blood cells and the outer plasma region, where the flow is governed by the Kuang and Luo (K–L) and the Newtonian fluids, respectively. Due to the presence of the glycocalyx layer and impurities near the vessel wall, the plasma region is further divided into three subregions, i.e., a non-porous layer adjacent to the central region, an intermediate transition Brinkman layer, and an outer Brinkman–Forchheimer region. The model accounts for spatial variations in permeability and fluid viscosity in the two outer porous regions. The regular perturbation method for high permeabilities and the singular perturbation method with matched asymptotic expansions for low permeabilities are applied to solve the momentum equations in porous regions to acquire the asymptotic solutions. The effect of external body forces has been studied through Froude number. The dependence of velocity, flow rate, and flow resistance on the numerous control parameters such as Froude number, Reynolds number, Kuang and Luo (K–L) fluid parameters, viscosity, and the porous medium parameters is analyzed graphically. Although the porous plasma region is thin, changes in its permeability measurably affect the velocity profile and derived flow quantities. The variation of plug-core velocity with Froude number indicates an increasing influence of inertial forces relative to gravitational forces. Specifically, as the Froude number increases, the flow profile experiences a deceleration, indicating that inertial effects become increasingly influential. The explanations could be informative for clinical applications, such as pulmonary hemodynamics and gastrointestinal anatomy. However, empirical validation remains an essential step in establishing the applicability of the results.

Photocatalysis is an eco-friendly and cost-effective approach for addressing the escalating issue of hazardous organic dye contamination in water bodies, enabling efficient pollutant degradation without generating toxic by-products. Herein, for the first time, tungsten-doped NiFe₂O₄ (W_0.05Ni_0.95Fe₂O₄) nanoparticles were synthesized via a one-step hydrothermal technique. The structural, morphological, and vibrational characteristics were examined using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDAX), and Raman spectroscopy. The photocatalytic efficiency of NiFe₂O₄ and W_0.05Ni_0.95Fe₂O₄ toward the degradation of Methylene Blue (MB) and Congo Red dyes under visible light irradiation was systematically investigated. Tungsten incorporation remarkably enhanced the degradation efficiency from 76% to 86% for MB dye compared to pristine NiFe₂O₄. Furthermore, pH-dependent studies revealed superior photocatalytic activity in basic media, achieving up to 98% degradation of MB at pH 14 within 140 minutes, with an increased rate constant of 0.0226 min⁻¹. These findings demonstrate that W_0.05Ni_0.95Fe₂O₄ nanoparticles serve as highly efficient visible-light-driven photocatalysts, offering great potential for practical applications in advanced wastewater treatment and environmental remediation.

Graphical Abstract

The boundary-driven flow of a micropolar fluid through a channel with a grooved wall has been investigated, emphasizing the influence of geometric and micropolar parameters on the flow characteristics. The study reveals that the presence of grooves significantly modifies the flow field by inducing additional angular velocity component. Substantial alterations in the stress distribution are observed, with corresponding effects on drag. Although the grooves generally increase drag, long-wavelength grooves are found to produce less drag than short-wavelength grooves. For the same geometric configuration, the results indicate that a Newtonian fluid experiences lower drag, underscoring the distinct influence of micropolar microstructure on flow behaviour. Furthermore, the presence of grooves reduces the flow rate in the channel relative to that in a smooth-walled configuration.

A deterministic SEIRV–SEI model is presented to investigate the transmission dynamics of yellow fever, involving human hosts and mosquito vectors. The model incorporates seasonally varying mosquito recruitment, disease-induced mortality in humans, and vaccination as a key intervention. Analytical and numerical simulations indicate that transmission rates from mosquitoes to humans ((beta)) and from humans to mosquitoes ((beta _v)) are critical in determining whether the infection dies out or persists at endemic levels, while vaccination ((nu)) can push the system towards a disease-free state. Phase-plane analyses demonstrate that higher (beta) or (beta _v) values increase the endemic equilibrium, while increasing (nu) reduces both outbreak size and long-term prevalence. Seasonal forcing amplifies epidemic peaks during high vector recruitment periods, highlighting the importance of sustained control strategies. Overall, the model underscores the importance of integrated vaccination and vector management, suggesting that intensifying immunisation before and during peak mosquito seasons is crucial to reducing outbreak risk and achieving long-term yellow fever control.