The European Physical Journal Plus最新文献

Using the analytic expression for the structure functions (F_2) and (F_L) of deep inelastic electron-proton scattering (DIS) derived from the color dipole picture (CDP), we can determine the gluon distribution of the proton at small Bjorken x. When the momentum transfer (Q^2) is sufficiently large, the extracted gluon distribution satisfies the standard evolution equation for the proton structure function. However, at low (Q^2), such as for (Q^2 = 1.9 textrm{GeV}^2), the gluon distribution functions shows a deviation from perturbative QCD (pQCD), indicating presence of non-perturbative, hadron-like contributions to DIS. The necessary modification is derived analytically as a result of the smooth transition in the CDP to the hadron-like interaction of the photon at low (Q^2) values.

In this paper, we focus upon the behaviour of spacetime of charged black holes described by Eddington-inspired Born-Infeld (EiBI) gravity. With a static and spherically symmetric metric, we solve the ensuing field equations obtained from the EiBI-Maxwell action in the Palatini formalism. Consequently we carry out, for the first time, an in-depth analysis of the structure of spacetime geometry in several regions of the charged EiBI black hole. In particular, we consider the analytical behaviours of the metric coefficients and the Kretschmann scalar by probing their asymptotic nature analytically in different regions of the black hole spacetime, such as, near the center, in the intermediate region, and near the horizon, for both positive and negative EiBI coupling. These analyses give a thorough understanding of the nature of spacetime of EiBI-Maxwell black holes. In order to aide our understanding further, we solve the EiBI-Maxwell field equation numerically with different values of the parameters involved. We find close agreement between the analytical behaviours and those obtained from numerical integration of the EiBI-Maxwell field equation.

This paper presents a biosensor based on a tunneling field-effect transistor with a heterogeneous right gate and an N⁺-pocket-enabled electron–hole bilayer. The device uses line tunneling through the electron–hole bilayer to obtain a large on-state current at low gate bias. The synergistic interaction between the control gate and the N⁺-pocket achieves an off-state current suppression effect in this device. Incorporating a vertical bio-cavity structure enhances biomolecule binding efficiency and chip integration density significantly. According to numerical simulations, the biosensor exhibits high sensitivity to neutral biomolecules of a high dielectric constant, as well as biomolecules of a high negative charge density, in addition to better on-state current sensitivity (S_Ion) under a low gate voltage. The results of optimization show that the device gives optimal performance with the bio-cavity width of 4 nm and length of 100 nm. Moreover, the biosensor shows remarkable stability over a broad temperature range, with important metrics including a S_Ion of 7 × 10⁶, a threshold voltage sensitivity of 5.8V, and an average subthreshold swing sensitivity of 0.95. The investigations are beneficial for the design of efficient biosensors.

In this work, we show a connection between superstatistics and position-dependent mass (PDM) systems in the context of the canonical ensemble. The key point is to set the fluctuation distribution of the inverse temperature in terms of the PDM of the system. For PDMs associated to Tsallis and Kaniadakis nonextensive statistics, the pressure and entropy of ideal gas result lower than the standard case but maintaining monotonic behavior. Gas of noninteracting harmonic oscillators provided with quadratic and exponential PDMs exhibits a behavior of standard 3D harmonic oscillator gas and a linear specific heat, respectively, the latter being consistent with Nernst’s third law of thermodynamics. Thus, a combined PDM-superstatistics scenario offers an alternative way to study the effects of the inhomogeneities of PDM systems in their thermodynamics.

This study explores the impact of the Kirchhoff index on modulation instability (MI) in Kagome photonic lattices with metamaterials. The unit cell of the lattice consists of three different waveguides with distinct optical properties, leading to a complex interplay between topology and nonlinearity. Our theoretical analysis reveals that the periodic MI exhibited by the lattice is suppressed as the Kirchhoff index of the discrete graph Laplacian of the lattice unit increases. Specifically, we find that a higher Kirchhoff index leads to a shrinking of the MI band and a decrease in the maximum gain. These findings provide valuable insights into the relationship between lattice topology and nonlinear optical behavior, shedding light on the intricate dynamics of MI in photonic lattices.

The composite films (PVA/Ni_0.05Cd_0.95O) were fabricated via the solution casting process by amalgamating the polymer Polyvinyl Alcohol (PVA) with varying amounts of nickel–cadmium oxide (NiCdO). The doping concentrations of NiCdO nanofillers are 0.7, 1.0, 1.5, and 2.0 wt%. The XRD confirms the successful manufacturing of the composite (PVA/NiCdO). The influence of filler Ni in the PVA/NiCdO on the surface morphology, optical and structural properties were examined. The FTIR measurement signifies the combination of Ni and CdO nanoparticles into PVA results in chemical interaction and physical amalgamation of the inorganic fillers with the polymer matrix. The optical characteristics, comprising optical absorbance, band gap energy, Urbach energy, refractive index and optical conductivity were determined using the UV/vis spectroscopy in wavelength of 200–1100 nm. The absorption edge transitions from 4.81 eV for PVA to 3.76 eV by increasing the Ni to 2.0% for PVA/NiCdO, while the band gap reduced from 5.32 to 3.01 eV. The incorporation of NiCdO into PVA polymer modifies its optical properties. The outcomes of this work provide empirical evidence for the potential application of PVA/NiCdO films in optical devices.

A (3+1)-dimensional three-component partially nonlocal nonlinear Schrödinger system with the harmonic trapping and distinct diffraction coefficients is studied by the dimensional reduction. Based on the Darboux approach, dark–bright–dark annular rogue wave approximate solutions are found, and precise control over the generation of successive excited states, including full, delayed, sustained, and inhibited excitations, is achieved. Moreover, annular structures of these dark–bright–dark rogue waves are studied.

The visual angle plays a pivotal role in the driving dynamics of connected vehicles (CVs) and human-driven vehicles (HDVs), influencing the overall stability of traffic flow. In a mixed traffic environments, the interactions between CVs and HDVs are primarily governed by perception-based dynamics, where each vehicle proceeds according to its perception of surrounding traffic conditions. To investigate this, a novel lattice hydrodynamic model is introduced to effectively study how visual angle impacts traffic dynamics in scenarios involving both CVs and HDVs. The traffic flow behavior is analyzed through linear stability analysis, where the neutral stability conditions are derived. Also, mKdV equation is attained near the critical point utilizing reduction perturbation technique. It is observed that as visual angle coefficient of human-driven and connected vehicles increases, the traffic flow becomes more stable. The numerical simulations are conducted to validate theoretical results. Further, based on power spectrum analysis, the spectral entropy is calculated, which reveals that the visual angle and the fraction of CVs positively impact the traffic flow stability. Additionally, the fluctuation patterns of average fuel consumption under the influence of these factors are systematically examined.

Many natural and physical processes can be understood by analyzing multiple system variables evolving, forming a multivariate time series. Predicting such time series is challenging due to the inherent noise and interdependencies among variables. Echo state networks (ESNs), a class of Reservoir Computing (RC) models, offer an efficient alternative to conventional recurrent neural networks by training only the output weights while keeping the reservoir dynamics fixed, reducing computational complexity. We propose a clustered ESNs (CESNs) that enhances the ability to model and predict multivariate time series by organizing the reservoir nodes into clusters, each corresponding to a distinct input variable. Input signals are directly mapped to their associated clusters, and intra-cluster connections remain dense, while inter-cluster connections are sparse, mimicking the modular architecture of biological neural networks. This architecture improves information processing by limiting cross-variable interference and enhances computational efficiency through independent cluster-wise training via ridge regression. We further explore different reservoir topologies, including ring, Erdős–Rényi (ER), and scale-free (SF) networks, to evaluate their impact predictive performance. Our algorithm works well across diverse real-world datasets such as the stock market, solar wind, and chaotic Rössler system, demonstrating that CESNs consistently outperform conventional ESNs in terms of predictive accuracy and robustness to noise, particularly when using ER and SF topologies. These findings highlight the adaptability of CESNs for complex, multivariate time series forecasting.

In the present work, we study a fermionic Lorentz invariance violation (LIV) theory with a CPT-even extension and analyse its impact on the Casimir effect under the MIT bag boundary condition model in a low-dimensional setting, where results are obtained without any approximations for a null temperature system. Moreover, the Matsubara formalism is applied to derive closed expressions for the influence of temperature on the physical observables: Casimir energy, Casimir force, and entropy associated with the system in a LIV context. For each thermal observable, the influence of the LIV correction term is considered in the analysis of both low- and high-temperature regimes. Additionally, we construct a condensed matter analogue using the SSH model, where nonlinear fermionic dispersion and boundary-induced vacuum energy emerge, reproducing the analytical structure of the LIV Casimir effect.