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Reconstructing parton distribution function based on maximum entropy method

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Chinese physics C 2024年第3期48卷 46-51页

作者：张思翰王晓斌林涛常雷 College of Chemistry Nankai UniversityTianjin 300071China School of physics Nankai UniversityTianjin 300071China

A new method based on the maximum entropy principle for reconstructing the parton distribution function(PDF)from moments is *** traditional methods,the new method does not require any artificial *** the case of moments with errors,we introduce Gaussian functions to soften the constraints of *** a series of tests,the effectiveness and reconstruction efficiency of this new method are evaluated comprehensively,demonstrating that this method is reasonable and can achieve high-quality reconstruction with at least the first six moments as ***,we select a set of lattice quantum chromodynamics(QCD)results regarding moments as input and provide reasonable reconstruction results for the pion.

关键词： parton distribution function maximum entropy method pion

Restoring cosmological concordance with axion-like early dark energy and dark matter characterized by a constant equation of state?

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Communications in Theoretical physics 2024年第7期76卷 74-82页

作者： Yan-Hong Yao Xin-He Meng School of physics and Astronomy Sun Yatsen University 2 Daxue RoadTangjiaZhuhaiChina School of physics Nankai University 94 Weijin RoadNankaiTianjinChina

The Hubble tension persists as a challenge in *** early dark energy(EDE)models,initially considered the most promising for alleviating the Hubble tension,fall short of addressing the issue without exacerbating other tensions,such as the S_(8)*** that a negative dark matter(DM)equation of state(EoS)parameter is conducive to reduce the value of the σ_(8)parameter,we extend the axion-like EDE model in this paper by replacing the cold dark matter(CDM)with DM characterized by a constant EoS w_(dm)(referred to as WDM hereafter).We then impose constraints on this axion-like EDE extension model,along with three other models:the axion-like EDE model,ΛWDM,and Λ*** constraints are derived from a comprehensive analysis incorporating data from the Planck 2018 cosmic microwave background,baryon acoustic oscillations,and the Pantheon compilation,as well as a prior on H_(0)(i.e.H_(0)=73.04±1.04,based on the latest local measurement by Riess et al)and a Gaussianized prior on S_(8)(i.e.S_(8)=0.766±0.017,determined through the joint analysis of KID1000+BOSS+2dLenS).We find that although the new model maintains the ability to alleviate the Hubble tension to~1.4σ,it still exacerbates the S_(8)tension to a level similar to that of the axion-like EDE model.

关键词： Hubble tension early dark energy noncold dark matter S8 tension

Flat Band and η-Pairing States in a One-Dimensional MoiréHubbard Model

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Chinese physics Letters 2024年第4期41卷 69-76页

作者：王冉宋智 College of physics and Materials Science Tianjin Normal UniversityTianjin 300387China School of physics Nankai UniversityTianjin 300071China

A Moirésystem is formed when two periodic structures have a slightly mismatched period,resulting in unusual strongly correlated states in the presence of particle-particle *** periodic structures can arise from the intrinsic crystalline order and periodic external *** investigate a one-dimensional Hubbard model with periodic on-site potential of period n_(0),which is commensurate to the lattice *** large n_(0),the exact solution demonstrates that there is a midgap flat band with zero energy in the absence of Hubbard *** Moiréunit cell contributes two zero energy levels to the flat *** the presence of Hubbard interaction,the midgap physics is demonstrated to be well described by a uniform Hubbard chain in which the effective hopping and on-site interaction strength can be controlled by the amplitude and period of the external *** simulations are performed to demonstrate the correlated behaviors in the finite-sized Moiré Hubbard system,including the existence of an η-pairing state and bound pair *** finding provides a method to enhance the correlated effect by a spatially periodic external field.

关键词： oscillation interaction field

Conductive catalysis by subsurface transition metals

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National Science Review 2024年第1期11卷 86-93页

作者： Xin Deng Caiyan Zheng Yangsheng Li Zeyu Zhou Jiamin Wang Yihua Ran Zhenpeng Hu Fan Yang Landong Li Frontiers Science Center for New Organic Matter College of ChemistryNankai University School of physics Nankai University School of Physical Science and Technology Shanghai Tech University School of Materials Science and Engineering Nankai University Haihe Laboratory of Sustainable Chemical Transformations

The nature of catalysis has been hotly pursued for over a century, and current research is focused on understanding active centers and their electronic structures. Herein, the concept of conductive catalysis is proposed and verified by theoretical simulations and experimental observations. Metallic systems containing buried catalytically active transitional metals and exposed catalytically inert main group metals are constructed, and the electronic interaction between them via metallic bonding is disclosed. Through the electronic interaction, the catalytic properties of subsurface transitional metals(Pd or Rh) can be transferred to outermost main group metals(Al or Mg) for several important transformations like semi-hydrogenation,Suzuki-coupling and hydroformylation. The catalytic force is conductive, in analogy with the magnetic force and electrostatic force. The traditional definition of active centers is challenged by the concept of conductive catalysis and the electronic nature of catalysis is more easily understood. It might provide new opportunities for shielding traditional active centers against poisoning or leaching and allow for precise regulation of their catalytic properties by the conductive layer.

关键词： electronic interaction conductive catalysis subsurface transition metal

Davidson base as an appropriate base for the shell model in the case of 1p- and 1h- nuclei

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Communications in Theoretical physics 2024年第10期76卷 94-100页

作者： Hadi Sobhani Yan-An Luo Amir Jalili Hassan Hassanabadi School of physics Nankai University Department of physics Zhejiang Sci-Tech University Institute of Theoretical physics Faculty of Physics University of Warsaw Institute of Actuarial Science and Data Analytics UCSI University

This study endeavors to develop an improved set of basis functions for nuclear shell-model calculations. The shell model, a well-established approach to understanding nuclear structure,typically employs the harmonic oscillator potential within the mean-field approximation. Given the extensive validation and consistency of harmonic oscillator results with experimental data,we propose a modification by incorporating a centrifugal term that converges toward the Davidson potential. This potential has been extensively studied, and we aim to extract relevant experimental data for the simplest cases in the shell model, namely one-particle and one-hole nuclei. A comprehensive comparison between the Davidson-based results and the harmonic oscillator calculations is presented to demonstrate the effectiveness of the new basis functions.

关键词： beta decay gamma transition nuclear structure shell-model calculations

Efficient second and third harmonic generation in dual-layer lithium niobate microdisk resonator

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Science China(physics,Mechanics & Astronomy) 2024年第5期67卷 33-38页

作者： Zhenzhong Hao Xiao Wu Qiang Luo Zhang Li Rui Ma Fang Bo Feng Gao Guoquan Zhang Jingjun Xu MOE Key Laboratory of Weak-Light Nonlinear Photonics TEDA Institute of Applied Physics and School of PhysicsNankai UniversityTianjin 300457China

Lithium niobate thin film frequency doubler has extensive applications in the preparation of classical and quantum *** this study,we successfully fabricated microdisk resonators with a quality factor of 2.2×10^(5) in reverse-polarization dual-layer x-cut lithium niobate for the first *** on the modal phase matching condition,efficient second harmonic generation with a record normalized conversion efficiency of~56000%W-1 and cascaded third harmonic generation with an efficiency of~6500%W-2 were obtained in the microdisk *** with the periodically poled lithium niobate microcavity,the complex domain structure preparation processes are *** work provides a scheme for achieving highly efficient second-order nonlinear effects in non-periodically poled microcavities.

关键词： harmonic lithium niobate

Global dust density in two-dimensional complex plasma

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Chinese physics B 2024年第6期33卷 445-450页

作者：赵逸真刘松芬孔伟杨芳 School of physics Nankai UniversityTianjin 300071China College of Science Civil Aviation University of ChinaTianjin 300300China

The driven-dissipative Langevin dynamics simulation is used to produce a two-dimensional(2D) dense cloud, which is composed of charged dust particles trapped in a quadratic potential. A 2D mesh grid is built to analyze the center-to-wall dust density. It is found that the local dust density in the outer region relative to that of the inner region is more nonuniform,being consistent with the feature of quadratic potential. The dependences of the global dust density on equilibrium temperature, particle size, confinement strength, and confinement shape are investigated. It is found that the particle size, the confinement strength, and the confinement shape strongly affect the global dust density, while the equilibrium temperature plays a minor effect on it. In the direction where there is a stronger confinement, the dust density gradient is bigger.

关键词： dust particles quadratic potential two-dimensional mesh grid

A method for determining the complex refractive index dispersion of absorbing materials without thickness information

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Optoelectronics Letters 2024年第11期20卷 676-680页

作者： DENG Zhichao MEI Jianchun WANG Jin YE Qing TIAN Jianguo Key Laboratory of Weak-Light Nonlinear Photonics Ministry of Education School of Physics and TEDA Applied Physics Nankai University

The complex refractive index dispersion(CRID) of absorbing materials is very important in many fields, especially in printing industry and medical research. However, due to their strong absorbing, CRID determination i... 详细信息

关键词： A

Molecular components in J/ψandρ-πpuzzle

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Chinese physics C 2024年第5期48卷 141-150页

作者：郭星导陈殿勇李学潜苑仲元桑士晶 College of physics and New Energy Xuzhou University of TechnologyXuzhou 221111China School of physics Southeast UniversityNanjing 211189China Department of physics Nankai UniversityTianjin 300071China Lanzhou Center for Theoretical physics Lanzhou UniversityLanzhou 730000China

Motivated by the large branching fractions of J/ψ→f0(1710)ω/f0(1710)ϕand the light exotic candidates,we found that there may exist molecular states composed of f0(1710)ωand f0(1710)ϕ,which correspond to X(2440)and X(2680)observed a few decades *** branching fractions of X(2440)and X(2680)to various PV and KKω(ϕ)channels were estimated in the molecular *** addition,the large branching fractions of J/ψ→f0(1710)ω/f0(1710)ϕindicate sizable molecular components in the J/ψ***,we consider J/ψas the superposition of thecc¯(1S),f0(1710)ω,and f0(1710)ϕmolecular *** molecular components have a significant impact on the light hadron decays of J/ψ,which may elucidate the long standingρ−πpuzzle.

关键词： ρ-πpuzzle J/ψ molecular state