arXiv subjects

Xiaopeng Wang

Publications and source records attributed to Xiaopeng Wang.

72 records · Page 4Linked to original sources

arXiv2023

Analytic solution of Balitsky-Kovchegov equation with running coupling constant using homogeneous balance method

In this study, we employ the homogeneous balance method to obtain an analytical solution to the Balitsky-Kovchegov equation with running coupling. We utilize two distinct prescriptions of the running coupling scale, namely the saturation scale dependent running coupling and the dipole momentum dependent running coupling. By fitting the proton structure function experimental data, we determine the free parameters in the analytical solution. The resulting $χ^{2}/d.o.f$ values are determined to be $1.07$ and $1.43$, respectively. With these definitive solutions, we are able to predict exclusive $J/ψ$ production, and demonstrate that analytical solutions with running coupling are in excellent agreement with $J/ψ$ differential and total cross section. Furthermore, our numerical results indicate that the analytical solution of the BK equation with running coupling can provide a reliable description for both the proton structure function and exclusive vector meson production.

hep-ph↗

arXiv2022

Page Entropy of Proton System in Deep-Inelastic-Scattering at Small-$x$

The partons model reveals the dynamical structure of nucleons (protons and neutrons). Studies related to thermodynamic quantities of nucleons are interesting and topical questions. In this work, for the first time we apply Page's theory of the studies of black hole to investigate the entropy of proton system. Inspired by the quantum entanglement entropy in black hole information theories, we establish the proton entanglement with the similar way. Based our calculations, the proton entanglement entropy has the approximate form $S = \ln m -1/2$, where $m$ represents the partons density of proton (mainly gluon and sea quark contributions) at small Bjorken $x$. Our calculations using Page's theory are well in agreement with the recent DIS measurements from H1 collaboration.

hep-ph↗

arXiv2022

Deep inelastic scattering with proton target in the presence of gluon condensation using holography

We study the deep inelastic scattering (DIS) of a proton-targeted lepton in the presence of gluon condensation using gauge/gravity duality. We use a modified $AdS_5$ background where the modification parameter $c$ corresponds to the gluon condensation in the boundary theory. Firstly, when examining the electromagnetic field, we find that non-zero $c$ can increase the magnitude of the field. Our goal is to find the acceptable value of $c$ for this scattering and our method is based on setting the mass of the proton as an eigenvalue of the baryonic state equations of the DIS to find the acceptable value of the parameter c on the other side of the equations. Therefore in the second step, we calculate wave function equations for the baryonic states where the mass of the proton target requires a value contribution of $c$ as $c = 0.0120 {\rm GeV}^4$. Proceeding by the electromagnetic field and the baryonic states, we derive the holographic interaction action related to the amplitude of the scattering. Finally, we compute the corresponding structure functions numerically as functions of $x$ and $q$, which are Bjorken variables and the lepton momentum transfers, respectively. Comparing the Jlab Hall $C$ data with our theoretical calculations, our results are acceptable.

hep-ph↗

arXiv2022

SFE-AI at SemEval-2022 Task 11: Low-Resource Named Entity Recognition using Large Pre-trained Language Models

Large scale pre-training models have been widely used in named entity recognition (NER) tasks. However, model ensemble through parameter averaging or voting can not give full play to the differentiation advantages of different models, especially in the open domain. This paper describes our NER system in the SemEval 2022 task11: MultiCoNER. We proposed an effective system to adaptively ensemble pre-trained language models by a Transformer layer. By assigning different weights to each model for different inputs, we adopted the Transformer layer to integrate the advantages of diverse models effectively. Experimental results show that our method achieves superior performances in Farsi and Dutch.

cs.CL↗

arXiv2022

Exclusive vector meson productions with the analytical solution of Balitsky-Kovchegov Equation

Exclusive vector meson production is an excellent probe for describing the structure of proton. In this paper, based on dipole model, the differential cross sections, total cross sections and the ratios of the longitudinal to transverse cross sections of $J/ψ$ and $ρ^0$ productions are calculated with the analytical solution of Balitsky-Kovchegov (BK) equation. In addition, we also consider the influences of two meson wave function models on the results. Our predictions, which are little sensitive to meson wave functions, agree with the experimental data. The analytical solution of BK equation is reliable for description of exclusive vector meson production in a certain range of $Q^2$.

hep-ph↗

arXiv2022

Pasta phases in neutron stars under strong magnetic fields

In the present work, we consider nuclear matter in the innermost crust of neutron stars under the presence of a strong magnetic field within the framework of a relativistic mean-field description. Two models with a different slope of the symmetry energy are considered in order to discuss the density-dependence of the equation of state on the crust structure. The non-homogeneous matter in $β$-equilibrium is described within the coexisting phases method, and the effect of including the anomalous magnetic moment is discussed. Five different geometries for the pasta structures are considered. It is shown that strong magnetic fields cause an extension of the inner crust of the neutron stars, with the occurrence of a series of disconnected non-homogeneous matter regions above the one existing for a null magnetic field. Moreover, we observed that in these disconnected regions, for some values of the magnetic field, all five different cluster geometrical shapes occur, and the gas density is close to the cluster density. Also, the pressure at the neutron star crust-core transition much larger than the pressure obtained for a zero magnetic field. Another noticeable effect of the presence of strong magnetic fields is the increase of the proton fraction, favoring the appearance of protons in the gas background.

nucl-th↗

arXiv2021

Novel Neutron Star Structures with Nucleon Mass Radius

In order to reveal the difference between the latest neutron star observation experiment GW170817 and the existing theory, we mainly consider the effect of the nucleon radius on the neutron star from the existing theory. We believe that the effect of nucleon radius in neutron star is not negligible, and the mass radius of nucleon should be used instead of the charge radius. The nucleon mass radius is set as $r_m = 0.55\pm0.09$ fm from the new measurements. It is considered as an input to the "Excluded Volume Effects" model in the equation of state of nuclear matter. We propose a novel neutron star mass-radius relation by using proton mass radius is consistent with the observation GW170817.

nucl-th↗

arXiv2021

Strong magnetic fields: neutron stars with an extended inner crust

Using relativistic mean-field models, the formation of clusterized matter, as the one expected to exist in the inner crust of neutron stars, is determined under the effect of strong magnetic fields. As already predicted from a calculation of the unstable modes resulting from density fluctuations at subsaturation densities, we confirm in the present work that for magnetic field intensities of the order of $\approx 5 \times 10^{16}$ G to $5 \times 10^{17}$ G, pasta phases may occur for densities well above the zero-field crust-core transition density. This confirms that the extension of the crust may be larger than expected. It is also verified that the equilibrium structure of the clusterized matter is very sensitive to the intensity of the magnetic fields. As a result, the decay of the magnetic field may give rise to internal stresses which may result on the yield and fracture of the inner crust lattice.

nucl-th↗

arXiv2021

An Analytical Solution of the Balitsky-Kovchegov Equation with the Homogeneous Balance Method

Nonlinear QCD evolution equations are essential tools in understanding the saturation of partons at small Bjorken $x_{\rm B}$, as they are supposed to restore an upper bound of unitarity for the cross section of high energy scattering. In this paper, we present an analytical solution of Balitsky-Kovchegov (BK) equation using the homogeneous balance method. The obtained analytical solution is similar to the solution of a traveling wave. By matching the gluon distribution in the dilute region which is determined from the global analysis of experimental data (CT14 analysis), we get a definitive solution of the dipole-proton forward scattering amplitude in the momentum space. Based on the acquired scattering amplitude and the behavior of geometric scaling, we present also a new estimated saturation scale $Q_s^2(x)$.

hep-ph↗

arXiv2021

Superconductivity and Charge Density Wave of CuIr2Te4 by Iodine Doping

Here we report a systematic investigation on the evolution of the structural and physical properties, including the charge density wave and superconductivity of the polycrystalline CuIr2Te4-xIx. X-ray diffraction results indicate that both of a and c lattice parameters increase linearly. The resistivity measurements indicate that the charge density wave is destabilized with slight x but reappears when x is large than 0.9. Meanwhile, the superconducting transition temperature enhances as x raises and reaches a maximum value of around 2.95 K for the optimal composition CuIr2Te3.9I0.1 followed by a slight decrease with higher iodine doping content. The specific heat jump for the optimal composition CuIr2Te3.9I0.1 is approximately 1.46, which is close to the Bardeen Cooper Schrieffer value which is 1.43, indicating it is a bulk superconductor. The results of thermodynamic heat capacity measurements under different magnetic fields, magnetization and magneto-transport measurements further suggest that CuIr2Te4-xIx bulks are type II superconductors. Finally, an electronic phase diagram for this CuIr2Te4-xIx system has been constructed. The present study provides a suitable material platform for further investigation of the interplay of the CDW and superconductivity.

cond-mat.supr-con↗

arXiv2020

Solitary wave solutions of FKPP equation using Homogeneous balance method(HB method)

In this paper, we use the homogeneous balance(HB) method is used to construct function transformation to solve the nonlinear development equation||Fisher-Kolomogror-Pertrovskii-Piskmov equation (FKPP equation), then the exact solution of FKPP equation is obtained, and the solutionis converted into the form of isolated wave solution. Finally, we have shown the solution of FKPPequation in some picture forms, and the rationality of the solution in this paper can be verified byusing the pictures.

nlin.PS↗

arXiv2020

Influence of Ln elements (Ln = La, Pr, Nd, Sm) on the structure and oxygen permeability of Ca-containing dual-phase membranes

Developing good performance and low-cost oxygen permeable membranes for CO2 capture based on the oxy-fuel concept is greatly desirable but challenging. Despite tremendous efforts in exploring new CO2-stable dual-phase membranes, its presence is however still far from meeting the industrial requirements. Here we report a series of new Ca-containing CO2-resistant oxygen transporting membranes with composition 60wt.%Ce0.9Ln0.1O2-40wt.%Ln0.6Ca0.4FeO3(CLnO-LnCFO; Ln = La, Pr, Nd, Sm) synthesized via a Pechini one-pot method. Our results indicate all investigated compounds are composed of perovskite and fluorite phases, while the perovskite phases in the CNO-NCFO and CSO-SCFO membranes after sintering generates Ca-rich and Ca-less two kinds of grains with different morphologies, where the Ca-less small perovskite grains block the transport of oxygen ions and eventually result in poor oxygen permeability. Among our investigated CLnO-LnCFO membranes, CPO-PCFO exhibits the highest oxygen permeability and excellent CO2 stability, which were mainly associated with the improvement in crystal symmetry, non-negligible electronic conductivity of fluorite phase and the enhancement in electronic conductivity of perovskite. Our results establish Ca-containing oxides as candidate material platforms for membrane engineering devices that combine CO2 capture and oxygen separation.

physics.app-ph↗

arXiv2019

Pion Valence Quark Distributions from Maximum Entropy Method

Valence quark distributions of pion at very low resolution scale $Q^{2}_0 \sim 0.1~GeV^2$ are deduced from a maximum entropy method, under the assumption that pion consists of only a valence quark and a valence anti-quark at such a low scale. Taking the obtained initial quark distributions as the nonperturbative input in the modified Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (with the GLR-MQ-ZRS corrections) evolution, the generated valence quark distribution functions at high $Q^2$ are consistent with the measured ones from a Drell-Yan experiment. The maximum entropy method is also applied to estimate the valence quark distributions at relatively higher $Q^2$ = 0.26 GeV$^{2}$. At this higher scale, other components (sea quarks and gluons) should be considered in order to match the experimental data. The first three moments of pion quark distributions at high $Q^2$ are calculated and compared with the other theoretical predictions.

hep-ph↗

arXiv2019

Temperature dependence of normalized sensitivity of Love wave sensor with unidirectional carbon fiber epoxy composite/Mn-doped 0.24PIN-0.46PMN-0.30PT ternary single crystal configuration

We have derived a general formula for sensitivity optimization of gravimetric sensors and use it to design a high precision and high sensitivity gravimetric sensor using unidirectional carbon fiber epoxy composite (CFEC) guiding layer on single crystal Mn-doped yPb(In1/2Nb1/2)O3-(1-x-y)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (Mn: PIN-PMN-PT) piezoelectric substrate. The normalized maximum sensitivity exhibits a decreasing tendency with temperature up to 55 degrees Celsius. For the CFEC-on-Mn: PIN-PMN-PT sensor configuration with wavelength 24 {mu}m at 25 degrees Celsius, the maximum sensitivity can reach as high as 760.88 cm2/g, which is nearly twice that of traditional SiO2/ST quartz configuration gravimetric sensor.

physics.app-ph↗

arXiv2018

Error-Control-Coding Assisted Imaging

Error-control-coding (ECC) techniques are widely used in modern digital communication systems to minimize the effect of noisy channels on the quality of received signals. Motivated by the fact that both communication and imaging can be considered as an information transfer process, in this paper we demonstrate that ECC could yield significant improvements in the image quality by reducing the effect of noise in the physical process of image acquisition. In the demonstrated approach, the object is encoded by ECC structured light fields generated by a digital-micromirror-device (DMD) while its image is obtained by decoding the received signal collected by a bucket-detector (BD). By applying a Luby Transform (LT) code as an example, our proof-of-concept experiment validates that the object image can be effectively reconstructed while errors induced by noisy reception can be significantly reduced. The demonstrated approach informs a new imaging technique: ECC assisted imaging, which can be scaled into applications such as remote sensing, spectroscopy and biomedical imaging.

eess.IV↗

arXiv2018

On the Possibility of Singlet Fission in Crystalline Quaterrylene

Singlet fission (SF), the spontaneous down-conversion of a singlet exciton into two triplet excitons residing on neighboring molecules, is a promising route to improving organic photovoltaic (OPV) device efficiencies by harvesting two charge carriers from one photon. However, only a few materials have been discovered that exhibit intermolecular SF in the solid state, most of which are acene derivatives. Recently, there has been a growing interest in rylenes as potential SF materials. We use many-body perturbation theory in the GW approximation and the Bethe-Salpeter equation (BSE) to investigate the possibility of intermolecular SF in crystalline perylene and quaterrylene. A new method is presented for determining the percent charge transfer character (%CT) of an exciton wave-function from double-Bader analysis. This enables relating exciton probability distributions to crystal packing. Based on comparison to known and predicted SF materials with respect to the energy conservation criterion (ES-2ET) and %CT, crystalline quaterrylene is a promising candidate for intermolecular SF. Furthermore, quaterrylene is attractive for OPV applications thanks to its high stability and narrow optical gap. Perylene is not expected to exhibit SF, however it is a promising candidate for harvesting sub-gap photons by triplet-triplet annihilation.

cond-mat.mtrl-sci↗

arXiv2015

Microwave Surveillance based on Ghost Imaging and Distributed Antennas

In this letter, we proposed a ghost imaging (GI) and distributed antennas based microwave surveillance scheme. By analyzing its imaging resolution and sampling requirement, the potential of employing microwave GI to achieve high-quality surveillance performance with low system complexity has been demonstrated. The theoretical analysis and effectiveness of the proposed microwave surveillance method are also validated via simulations.

stat.AP↗

arXiv2012

Hybrid density functional study of band alignment in ZnO/GaN and ZnO/(Ga1-xZnx)(N1-xOx)/GaN heterostructures

The band alignment in ZnO/GaN and related heterostructures are crucial for the uses in solar harvesting technology. Here, we report our density functional calculations of the band alignment and optical properties of ZnO/GaN and ZnO/(Ga1-xZnx)(N1-xOx)/GaN heterostructures using a Heyd-Scuseria-Ernzerhof (HSE) hybrid functional. We found that the conventional GGA functionals underestimate not only the band gap but also the band offset of these heterostructures. Using the hybrid functional calculations, we show that the (Ga1-xZnx)(N1-xOx) solid solution has a direct band gap of about 2.608 eV, in good agreement with the experimental data. More importantly, this solid solution forms type-II band alignment with the host materials. A GaN/(Ga1-xZnx)(N1-xOx)/ZnO core-shell solar cell model is presented to improve the visible light adsorption ability and carrier collection efficiency.

cond-mat.mtrl-sci↗