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Chinese physics C 2023年第7期47卷 138-150页

作者：杜晓凯郭鹏吴鑫辉张双全 state key laboratory of nuclear physics and technology School of PhysicsPeking UniversityBeijing 100871China

The kernel ridge regression(KRR)method and its extension with odd-even effects(KRRoe)are used to learn the nuclear mass table obtained by the relativistic continuum Hartree-Bogoliubov theory.With respect to the binding energies of 9035 nuclei,the KRR method achieves a root-mean-square deviation of 0.96 MeV,and the KRRoe method remarkably reduces the deviation to 0.17 MeV.By investigating the shell effects,one-nucleon and twonucleon separation energies,odd-even mass differences,and empirical proton-neutron interactions extracted from the learned binding energies,the ability of the machine learning tool to grasp the known physics is discussed.It is found that the shell effects,evolutions of nucleon separation energies,and empirical proton-neutron interactions are well reproduced by both the KRR and KRRoe methods,although the odd-even mass differences can only be reproduced by the KRRoe method.

关键词： machine learning kernel ridge regression relativistic continuum Hartree-Bogoliubov theory nuclear mass table

From Topological Nodal-Line Semimetals to Quantum Spin Hall Insulators in Tetragonal SnX Monolayers(X=F,Cl,Br,I)

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Chinese physics Letters 2024年第6期41卷 98-111页

作者：朱晔赵宝薛阳徐玮徐文婷杨中芹 state key laboratory of Surface physics Key Laboratory of Computational Physical Sciences(MOE)and Department of PhysicsFudan UniversityShanghai 200433China Shandong key laboratory of Optical Communication Science and technology School of Physics Science and Information TechnologyLiaocheng UniversityLiaocheng 252059China school of physics East China University of Science and TechnologyShanghai 200237China Shanghai Qi Zhi Institute Shanghai 200030China

Two-dimensional(2D)topological materials have recently garnered significant interest due to their profound physical properties and promising applications for future quantum nanoelectronics.Achieving various topological states within one type of materials is,however,seldom reported.Based on first-principles calculations and tightbinding models,we investigate topological electronic states in a novel family of 2D halogenated tetragonal stanene(T-SnX,X=F,Cl,Br,I).All the four monolayers are found to be unusual topological nodal-line semimetals(NLSs),protected by a glide mirror symmetry.When spin-orbit coupling(SOC)is turned on,T-SnF and TSnCl are still ascertained as topological NLSs due to the remaining band inversion,primarily composed of Sn pxy orbitals,while T-Sn Br and T-SnI become quantum spin Hall insulators.The phase transition is ascribed to moving up in energy of Sn s orbitals and increasing of SOC strengths.The topology origin in the materials is uniformly rationalized through elementary band representations.The robust and diverse topological states found in the 2D T-SnX monolayers position them as an excellent material platform for development of innovative topological electronics.

关键词： topological metals quantum

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质子滴线外原子核的多质子发射研究进展

Science Bulletin 2023年第7期68卷 645-647页

作者：华辉 school of physics and state key laboratory of nuclear physics and technology Peking UniversityBeijing 100871China

As a complex quantum finite many-body system,the nucleus is bound by the strong interaction between nucleons.Departing from the β-stability line,if protons/neutrons are continuously added,the valence protons/neutrons become less and less bound,and ultimately the nuclear force can no longer bind the nucleons together and consequently the proton/neutron dripline comes at vanishing binding energies.With the advent of radioactive nuclear beam devices,the nuclear landscape has been greatly expanded in the region far from the β-stability line in the past decades.

关键词：质子滴线 stability expanded

Backflow Transformation for A=3 Nuclei with Artificial Neural Networks

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原子能科学技术 2023年第4期57卷 673-678页

作者： YANG Yilong ZHAO Pengwei state key laboratory of nuclear physics and technology School of PhysicsPeking UniversityBeijing 100871China

A novel variational wave function defined as a Jastrow factor multiplying a backflow transformed Slater determinant was developed for A=3 nuclei.The Jastrow factor and backflow transformation were represented by artificial neural networks.With this newly developed wave function,variational Monte Carlo calculations were carried out for3H and3He nuclei starting from a nuclear Hamiltonian based on the leadingorder pionless effective field theory.The obtained ground-state energy and charge radii were successfully benchmarked against the results of the highly-accurate hypersphericalharmonics method.The backflow transformation plays a crucial role in improving the nodal surface of the Slater determinant and,thus,providing accurate ground-state energy.

关键词： nuclear many-body problem quantum Monte Carlo artificial neural network backflow transformation

Simulation study of the performance of quadruple-GEM detectors

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Radiation Detection technology and Methods 2023年第1期7卷 107-116页

作者： Yue Wang Licheng Zhang Aera Jung Dayong Wang Yong Ban state key laboratory of nuclear physics and technology Physics SchoolPeking UniversityBeijing100871China

Background Gas Electron Multiplier(GEM)detectors are widely used for high-energy physics experiments,such as the triple-GEM detector installed in CMS,due to their excellent performance.A quadruple-GEM detector is regarded as the candidate for the upgrade projects of the High Luminosity LHC(HL-LHC).Method In this paper,key performance characteristics of quadruple-GEM detectors are studied in detail based on Monte Carlo simulation using the Garfield++and ANSYS software packages.The parameterization method is adopted.Result The spatial and time resolution,effective gain,efficiency,and electron transparency are obtained via simulation for different detector geometries and operating conditions.We create a quadruple-GEM structure that meets the geometric requirements of the CMS endcap muon detectors.Conclusion These studies help to understand the physical mechanisms of GEM detectors and provide references for the detector design,operating condition optimization and technical scheme selection in future applications.

关键词： Quadruple-GEM Monte Carlo simulation Resolution Gain Electron transparency Efficiency

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^(16)O具有类Hoyle结构的新证据

Science Bulletin 2023年第11期68卷 1119-1126,M0003页

作者：陈家豪叶沿林马凯韩家兴王东玺林承键贾会明杨磊李根阳黎升胡梓瑶谭智威魏康蒲伟良陈莹楼建玲杨晓菲李奇特杨再宏骆天鹏黄大湖钟善豪李智焕许金艳 school of physics and state key laboratory of nuclear physics and technology Peking UniversityBeijing 100871China China Institute of Atomic Energy Beijing 102413China College of physics and technology&Guangxi key laboratory of nuclear physics and technology Guangxi Normal UniversityGuilin 541004China

多年来的研究认为,^(12)C中位于7.65 MeV的第二个0+态,也就是通常说的Hoyle state,具有类似玻色爱因斯坦凝聚(BEC)的状态.但对于更重的核体系,如^(16)O,^(20)Ne,^(24)Mg等,尽管已有多种理论预言,但多年来对于类BEC态的实验研究尚未给出... 详细信息

多年来的研究认为,^(12)C中位于7.65 MeV的第二个0+态,也就是通常说的Hoyle state,具有类似玻色爱因斯坦凝聚(BEC)的状态.但对于更重的核体系,如^(16)O,^(20)Ne,^(24)Mg等,尽管已有多种理论预言,但多年来对于类BEC态的实验研究尚未给出明确的结论.近期北京串列加速器国家实验室开展的非弹散射实验给出了^(16)O中存在类似4α-BEC状态的新证据.实验使用96 MeV的^(16)0束流轰击0.98μm的^(12)C靶,采用多套双面硅微条带电粒子望远镜对反应末态粒子进行探测,在^(16)O衰变中实现了4个α粒子的准确识别(PID)和符合测量.在此基础上获得了高分辨的反应Q值谱并重建了清晰的4α共振态.其中在阈值附近观察到4个高显著度(大部分高于5σ)的共振态,它们按照^(12)C(Hoyle state)+α的特征模式衰变,与理论预言的类Hoyle-BEC结构及其转动带特征相一致.本观测结果将推动进一步的理论研究,以及实验上对上述共振态做更多物理量的观测.

关键词：带电粒子转动带共振态末态粒子特征模式理论预言串列加速器符合测量

质子滴线外原子核的多质子发射研究进展（英文）

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Science Bulletin 2023年第7期 645-647页

作者：华辉 school of physics and state key laboratory of nuclear physics and technology Peking University

As a complex quantum finite many-body system, the nucleus is bound by the strong interaction between nucleons. Departing from the β-stability line, if protons/neutrons are continuously added, the valence protons/neutrons become less and less bound, and ultimately the nuclear force can no longer bind the nucleons together and consequently the proton/neutron dripline comes at vanishing binding energies.

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Digital signal acquisition system for complex nuclear reaction experiments

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nuclear Science and Techniques 2024年第1期35卷 124-133页

作者： Wei-Liang Pu Yan-Lin Ye Jian-Ling Lou Jia-Hao Chen school of physics and state key laboratory of nuclear physics and technology Peking UniversityBeijing 100871China Institute of Applied physics and Computational Mathematics Beijing 100094China

A digital data-acquisition system based on XIA LLC products was used in a complex nuclear reaction experiment using radioactive ion beams.A flexible trigger system based on a field-programmable gate array(FPGA)parametrization was developed to adapt to different experimental sizes.A user-friendly interface was implemented,which allows converting script language expressions into FPGA internal control parameters.The proposed digital system can be combined with a conventional analog data acquisition system to provide more flexibility.The performance of the combined system was veri-fied using experimental data.

关键词： Digital signal acquisition system Trigger Programmable logic Timestamp

Ion implantation assisted synthesis of graphene on various dielectric substrates

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Nano Research 2021年第5期14卷 1280-1286页

作者： Yunbiao Zhao Yue li Yi Chen Yuhan Chen Danqing Zhou Ziqiang Zhao state key laboratory of nuclear physics and technology School of PhysicsPeking UniversityBeijing100871China

Direct synthesis of high-quality graphene on dielectric substrates is of great importance for the application of graphene-based electronics and optoelectronics. However, high-quality and uniform graphene film growth on dielectric substrates has proven challenging due to limited catalytic ability of dielectric substrates. Here, by employing a Cu ion implantation assisted method, high-quality and uniform graphene can be directly formed on various dielectric substrates including SiO2/Si, quartz glass, and sapphire substrates. The growth rate of graphene on the dielectric substrates was significantly improved due to the catalysis of Cu. Moreover, during the graphene growth process, the Cu atoms gradually evaporated away without involving any metal contamination. Furthermore, an interesting growth behavior of graphene on sapphire substrate was observed, and the results show the graphene domains growth tends to grow along the sapphire flat terraces. The ion implantation assisted approach could open up a new pathway for the direct synthesis of graphene and promote the potential application of graphene in electronics.

关键词： graphene chemical vapor deposition(CVD) ion implantation dielectric substrates

Global analysis of Skyrme forces with higher-order density dependencies

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Chinese physics C 2018年第6期42卷 101-109页

作者：左致玮裴俊琛熊雪宇朱怡 state key laboratory of nuclear physics and technology School of PhysicsPeking University

The density-dependent term in Skyrme forces is essential to simulate three-body and many-body correlations beyond the low-momentum two-body interaction. We speculate that a single density term may be insumcient and a higher-order density dependent term is added. The present work investigates the influence of higher-order density dependencies based on extended UNEDF0 and SkM＊ forces. Global descriptions of nuclear masses and charge radii are presented. The extended UNEDF0 force gives a global rms error on binding energies of 1.29 MeV. The influence on fission barriers and equation of state are also investigated. Perspectives to improve Skyrme forces are discussed, including global center-of-mass corrections and Lipkin-Nogami pairing corrections.

关键词： Skyrme forces nuclear masses nuclear energy density functional