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Empirical Pairing gaps and neutron-proton correlations

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Chinese Physics C 2019年第1期43卷 109-121页

作者： B.S.Ishkhanov S.V.Sidorov T.Yu.Tretyakova E.V.Vladimirova Faculty of Physics Lomonosov Moscow State University Skobeltzyn Institute of Nuclear Physics Lomonosov Moscow State University

Analysis of various mass formulas related to neutron-proton correlations in atomic nuclei is carried out.Using the example of the N =Z chain it is shown that for self-adjoint nuclei various formulas proposed in literature for estimating the np Pairing energy lead to similar results. Significant differences between the calculation methods arise when nuclei with N = Z are considered, which allows to reveal the complexity of neutron-proton correlations in different types of atomic nuclei and to make assumptions on the correspondence of the mass relation to the real effect of np Pairing. The Shell Model parametrization of the binding energy makes it possible to draw additional conclusions on the structure of mass formulas and their relationship.

关键词： nucleon interaction models of atomic nuclei nucleon Pairing in atomic nuclei

A strongly secure Pairing-free certificateless authenticated key agreement protocol under the CDH assumption

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Science China(Information Sciences) 2016年第3期59卷 107-122页

作者： Haiyan SUN Qiaoyan WEN Wenmin LI State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Zhengzhou University of Light Industry

Certificateless authenticated key agreement(CL-AKA) protocols have been studied a great deal since they neither suffer from a heavy certificate management burden nor have the key escrow problem. Recently, many efficient CL-AKA protocols without Pairings have been built. However, these Pairing-free CL-AKA protocols are either not proved in any formal security model or proved under the gap Diffie-Hellman(GDH)assumption, a non-standard and strong assumption. With available implementation technologies, Pairings are needed to realize the GDH assumption, which means that these Pairing-free CL-AKA protocols are not pure Pairing-free. Furthermore, these protocols are insecure in the strengthened e CK(se CK) model, which encompasses the e CK model and considers leakages on intermediate results. In this paper, we present a pure Pairing-free CL-AKA protocol, which is provably secure in the se CK model under the standard computational Diffie-Hellman(CDH) assumption. Compared with the existing CL-AKA protocols, the proposed protocol has advantage over them in security or efficiency.

关键词： CDH assumption se CK model Pairing certificateless cryptography authenticated key agreement

Impurity-induced bound states as a signature of Pairing symmetry in multiband superconducting CeCu2Si2

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Frontiers of physics 2019年第1期14卷 99-104页

作者： Dong-Dong Wang Bin Liu Min Liu Yi-Feng Yang Shi-Ping Feng Department of Physics Beijing Jiaotong University Beijing 100044 China Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China Collaborative Innovation Center of Quantum Matter Beijing 100190 China Department of Physics Beijing Normal University Beijing 100875 China

The notion of multiband superconductivity with dominant two-gap features has been recently applied to the unconventional superconductor CeCu2Si2 for challenging the previously accepted concept of nodal d-wave Pairing. In the proposed study, the realistic multiband Fermi surface topology of CeCu2Si2 was obtained through first-principles calculations, and analysis was conducted with an effective two-band hybridization model including detailed band structure. Within the T-matrix approximation, the obtained calculation results show that different Pairing candidates, including fully gapped s-wave, loop-nodal s-wave, and d-wave Pairings, could yield qualitatively distinct features characterized by impurity-induced bound states. These features can be verified through high-resolution scanning tunneling microscopy or spectroscopy and provide corroborative justification that would be beneficial for the ongoing research regarding the superconducting gap symmetry of CeCu2Si2 at ambient pressure.

关键词： heavy-fermion superconductivity Pairing symmetry impurity effect local density of states

Thoughts on Pairing Assistance to Tibet for Promoting Agricultural High-quality Development in Southern Tibet from the Perspective of Agricultural Power

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Asian Agricultural Research 2024年第3期16卷 18-24页

作者： Zhiguo SUN Li GAO Yuanpeng SUN Guangchao CAO Xinying ZHOU Xiaoqiang LI Hubei University of Science and Technology Xianning 437100China Academy of Plateau Science and Sustainability of People s Government of Qinghai Province&Beijing Normal University Xining 810008China Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of SciencesBeijing 100044China

In the new era,there is an urgent need to further promote Pairing assistance to Tibet,promote the simultaneous construction of a strong agriculture in Tibet and the China's Mainland,and compose a Chinese-style modernization.Southern Tibet,located in the southeastern part of the Tibet Autonomous Region,includes Shannan City and Nyingchi City,is a region assisted by four provincial partners including Hubei Province.This paper introduces the agricultural environment in southern Tibet,studies its agricultural characteristics,and analyzes the main issues of its Pairing assistance.Taking forging the strong consciousness of the Chinese national community as the main line,the paper explores strategies for promoting agricultural high-quality development in southern Tibet through Pairing assistance to Tibet from the perspective of agricultural power,and proposes some strategies,such as inheriting agricultural cultural heritage,promoting the upgrading of modern seed industry,enhancing the characteristic advantages of highland barley(naked barley)and animal husbandry industries,and developing edible fungi and cold water fish industries.

关键词： Pairing assistance to Tibet Southern Tibet Shannan City Nyingchi City Agricultural high-quality development Agricultural power

Effects of Pairing correlation on neutron drop

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Science China(Physics,Mechanics & Astronomy) 2020年第4期63卷 88-97页

作者： Ying-Hui Ge Ying Zhang Jin-Niu Hu Department of Physics School of ScienceTianjin UniversityTianjin 300072China School of Physics Nankai UniversityTianjin 300071China

In this work, the effects of the Pairing correlation on the properties of neutron drops N=6-50 trapped in a harmonic oscillator potential with ω = 10 Me V are investigated by comparing the results given by the Skyrme Hartree-Fock and Hartree-FockBogoliubov theories with the density-dependent delta interaction(DDDI) Pairing force. The results showed that the Pairing correlation slightly made the neutron drops more bound, and increased the central neutron density, the spin-orbit and pseudo spin-orbit splittings. Thus, the Pairing correlation must be accounted for to improve the Skyrme functional compared with the ab initio calculations. Furthermore, although the single-particle energy gaps with or without Pairing were similar, the shell closures varied due to pair scattering. Here, the shell closures in neutron drops using the Sk M* parameter set and DDDI Pairing force were found at N=8, 16, and 32.

关键词： neutron drop Hartree-Fock theory Hartree-Fock-Bogoliubov theory Pairing correlation

Effects of mean-field and Pairing correlations on the Bogoliubov quasiparticle resonance

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Science China(Physics,Mechanics & Astronomy) 2019年第11期62卷 93-101页

作者： XiaoYing Qu Ying Zhang School of Physics and Nuclear Energy Engineering Beihang UniversityBeijing 100191China School of Mechatronics Engineering Guizhou Minzu UniversityGuiyang 550025China Department of Physics School of ScienceTianjin UniversityTianjin 300072China

The quasiparticle resonances are investigated by examining three kinds of quasiparticle spectra, i.e., the density of quasiparticle states, the occupation number density, and the pair number density in the continuum Skyrme Hartree-Fock-Bogoliubov theory with the Green’s function method. Taking the weakly bound nucleus 66Ca as an example, the quasiparticle resonant energies and widths extracted from these three kinds of quasiparticle spectra are compared. For the narrow resonances, the extracted resonant energy and the width are consistent with each other. However, it is difficult to use the density of quasiparticle states to identify the broad resonances due to the background of nonresonant continuum. By switching off the Pairing potential and/or the Hartree-Fock(HF) potential respectively in the calculation of these quasiparticle spectra, the roles of HF mean-field and Pairing correlations in the quasiparticle resonances are demonstrated clearly. It turns out that all the quasiparticle resonances corresponding to the deeply bound, weakly bound and positive-energy single-particle resonant states, are mainly contributed by the HF potential. The Pairing potential helps to slightly increase the resonant energy and the width. However, the Pairing potential is important to make the nucleons occupy the low-lying nonresonant continuum states near the threshold and take part in the Pairing correlations here,especially for the partial waves with small angular momentum ?.

关键词： quasiparticle resonance mean-field Pairing correlations Skyrme Hartree-Fock-Bogoliubov theory Green’s function method

Quantum Monte Carlo study of the dominating Pairing symmetry in doped honeycomb lattice

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Chinese Physics B 2019年第7期28卷 434-438页

作者：朱兴川应涛郭怀明冯世平 Department of Physics Beijing Normal University Beijing 100875 China Department of Physics Harbin Institute of Technology Harbin 150001 Chin Department of Physics Key Laboratory of Micro-Nano Measurement-Manipulation and Physics(Ministry of Education) Beihang University Beijing 100191 China

We perform a systematic determinant quantum Monte Carlo(DQMC) study of the dominating Pairing symmetry in a doped honeycomb lattice.The Hubbard model is simulated over a full range of filling levels for both weak and strong interactions.For weak couplings, the d-wave state dominates.The effective susceptibility as a function of filling shows a peak, and its position moves toward half filling as the temperature is increased, from which the optimal filling of the superconducting ground state is estimated.Although the sign problem becomes severe for strong couplings, the simulations access the lowest temperature at which the DQMC method generates reliable results.As the coupling is strengthened, the d-wave state is enhanced in the high-filling region.Our systematic DQMC results provide new insights into the superconducting Pairing symmetry in the doped honeycomb lattice.

关键词： determinant quantum Monte Carlo(DQMC) simulation honeycomb lattice superconducting Pairing symmetry

Pairing Effects on Bubble Nuclei

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Chinese Physics Letters 2019年第3期36卷 24-27页

作者：王艳召李洋亓冲顾建中 Department of Mathematics and Physics Shijiazhuang Tiedao University Institute of Applied Physics Shijiazhuang Tiedao University Department of Physics Royal Institute of Technology (KTH) China Institute of Atomic Energy

In the framework of the Skyrme–Hartree–Fock–Bogoliubov approach with the Sk T interaction, the Pairing effects on the proton bubble structures of ^(46)Ar and ^(206)Hg are discussed. In calculations, three kinds of Pairing forces (volume, surface and mixed Pairing interactions) are used. For ^(46)Ar, it is shown that the bubble structure with the volume Pairing is almost the same as that with the mixed Pairing. The bubble with the surface Pairing is less pronounced than those with the volume and mixed Pairings. Analyzing the density distributions and occupation probabilities of the proton s states and the quasi-degeneracy between the proton 2s_(1/2) and 1d_(3/2) orbitals, we explain the difference between the bubble structure with the surface Pairing and those with the volume and mixed Pairings. For ^(206)Hg, it is seen that the proton density distribution with the surface Pairing is different from those with the volume and mixed Pairings in the whole region of the radial distance. In addition, it is found that the bubbles with the three Pairing forces are different from each other and the least pronounced bubble is obtained with the surface Pairing. Thus the selection of the Pairing force is important for the study of the nuclear bubble structure.

关键词： Pairing Effects Bubble Nuclei Hg

Pairing and Quantum Double of Finite Hopf C~*-Algebras

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Acta Mathematica Sinica,English Series 2007年第6期23卷 1121-1128页

作者： Ming LIU Li Ning JIANG Guo Sheng ZHANG Department of Mathematics Beijing Institute of Technology Beijing 100081 P. R. China

This paper defines a Pairing of two finite Hopf C^＊-algebras A and B, and investigates the interactions between them. If the Pairing is non-degenerate, then the quantum double construction is given. This construction yields a new finite Hopf C^＊-algebra D（A, B）. The canonical embedding maps of A and B into the double are both isometric.

关键词： Hopf C^＊-algebra Pairing quantum double GNS representation