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2004年  第21卷  第2期

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论文
重离子物理和交叉学科研究及CSR工程进展
靳根明
2004, 21(2): 73-76. doi: 10.11804/NuclPhysRev.21.02.073
摘要:
综述了近年来中国科学院近代物理研究所在新核素合成研究、同位旋效应研究、高自旋态性质研究及交叉学科研究方面取得的进展, 简述了国家重大科学工程——兰州重离子加速器,冷却储存环(CSR)的主要设计改进、建设内容以及近期各系统的建设进展.
五夸克态Θ的手征夸克模型研究(英文)
张宗烨, 黄飞, 余友文, 邹冰松
2004, 21(2): 77-80. doi: 10.11804/NuclPhysRev.21.02.077
摘要:
在手征夸克模型的框架下, 研究了五夸克态 uudd的结构. 分别考虑了 Jπ=(1/2)-和Jπ=(1/2)+的各四个组态. 结果表明对于不同的模型, 不论 Jπ=(1/2)-和 Jπ=(1/2)+, T=0的态的能量总是最低的. 但是最低态的能量的理论计算值仍比Θ质量的实验值高250—300 MeV.
直接从QCD拉氏量研究禁闭的尝试
朱重远
2004, 21(2): 81-82. doi: 10.11804/NuclPhysRev.21.02.081
摘要:
对SU(N)情形, 应用法捷耶夫和尼米的非阿贝尔规范势的拓扑分解, 在路径积分中, 将除拓扑自由度以外的其它自由度积掉, 求出单圈和低能近似下的有效作用量. 结果支持由对偶迈斯纳效应造成色禁闭的图像. 也讨论了费米子场的效应. In the SU(N) case we use the FadeevNiemi topological decomposition of nonabelian gauge potentials to derive the low energy effective Lagrangian under one loop approximation by integrating all degrees of freedom except the topological ones in its path integral. The result supports a mechanism on color confinment which comes from the dual Misner Effect. The effect from fermion fields is also discussed.
多体体系输运理论——反常扩散
卓益忠
2004, 21(2): 83-85. doi: 10.11804/NuclPhysRev.21.02.083
摘要:
主要介绍最近在多体体系输运理论的一些模型和动力学等工作, 特别是一些有关反常扩散方面的工作结果.
中能重离子碰撞过程中同位旋分馏的特征和机制
刘建业, 邢永忠, 郭文军
2004, 21(2): 86-89. doi: 10.11804/NuclPhysRev.21.02.086
摘要:
利用同位旋依赖的QMD模型主要对中能重离子碰撞中同位旋分馏机制和主要特征进行了讨论和分析, 得到了一些有趣的结果, 并建议将同位旋分馏强度作为提取同位旋相关平均场和建立同位旋不对称核物质状态方程的探针. The degree of isospin fractionation is measured by (N/Z)gas / (N/Z)liq,where (N/Z)gas and (N/Z)liq are the saturated neutronproton ratio of nucleon emissions ( gas phase) and that of fragment emitted (liquid phase) in heavy ion collision at intermediate energy. The calculated results by using the isospindependent quantum molecular dynamics model show that the degree of isospin fractionation is sensitive to the neutronproton ratio of colliding system. In particular, the degree of isospin fractionation sensitively depends on the symmetry potential and weakly on the inmedium nucleonnucleon cross section for the neutronrich system. In this case, we propose that the degree of isospin fractionation can be directly compared with the experimental data so that the information about symmetry potential can be obtained.
相对论无规位相近似
马中玉
2004, 21(2): 90-92. doi: 10.11804/NuclPhysRev.21.02.090
摘要:
讨论了建立在相对论平均场基态的相对论无规位相近似研究中的一致性问题. 研究表明考虑费米海和Dirac海的粒子空穴激发对核的同位旋标量巨共振的能量有很大的影响.
The fully consistent relativistic random phase approximation (RRPA) built on the relativist mean field (RMF) ground state is presented. The fully consistent RRPA requires that the nuclear RMF wave function and the RRPA renormalization are calculated in a same effective Lagrangian. A theoretically complete treatment of the RRPA at the mean field level with no sea approximation must include not only the usual particlehole states, but also the pairs formed from the occupied Fermi states and Dirac states. Effects of inclusion of Dirac sea states in various multipole excitations are investigated. Considerable effects on the isoscalar giant multipole resonances are observed.
夸克的横向性分布与核子张量荷
何汉新
2004, 21(2): 93-95. doi: 10.11804/NuclPhysRev.21.02.093
摘要:
夸克的横向性分布的一次矩定义了核子张量荷. 核子张量荷也可用张量流算符在核子态的矩阵元定义,由此用量子色动力学求和规则、有效理论和模型计算了核子张量荷. 对研究核子性质及强子物理的自洽非微扰途径问题也作了简要讨论. The first moment of quark transversity distribution defines the tensor charge of nucleon. The tensor charge of nucleon can also be defined as the forward matrix element of the tensor current in the nucleon state,which is used to study the nucleon’s tensor charge in terms of quantum color dynamics(QCD) sum rule approach, the effective theory and model. A consistent nonperturbative approach to study nucleon property and hadronic physics is also discussed.
通过J/Ψ→NM衰变研究N~*时的核子极点效应
沈彭年, 梁伟红, 邹冰松
2004, 21(2): 96-98. doi: 10.11804/NuclPhysRev.21.02.096
摘要:
研究了J/Ψ→pp^-π衰变过程中核子极点图的贡献,特别是由离壳效应带来的贡献.发现衰变宽度对形状因子是敏感的.在通过用J/Ψ→pp^-π衰变研究N^*时,核子极点图作为背景道的贡献是非常重要的;在通过J/Ψ→pp^-η和pp^-η研究N^*时,核子极点图的贡献可忽略不计;在通过J/Ψ→pp^-ω研究N^*时,核子极点图有明显的贡献.
N-pole contributions, especially due to off shell effect, in J/Ψ→ NM decays are
carefully studied. It is found that the decay width is sensitive to the form factor. The Npole contribution as a background is important in the J/Ψ→Nπ decay, ignorable in the J/Ψ→Nη and Nη' decays, and sizable in the J/Ψ→Nω decay.
玻色子多体系统的平均场理论:玻色-爱因斯坦凝聚体(BEC)的冷却与激发
王顺金
2004, 21(2): 99-103. doi: 10.11804/NuclPhysRev.21.02.099
摘要:
用量子主方程的平均场近似和代数动力学研究玻色-爱因斯坦凝聚体的sympathetic cooling; 用玻色-爱因斯坦凝聚体波函数的运动方程的平均场近似非线性薛定谔方程研究玻色爱因斯坦凝聚体的暗孤子和明孤子激发.
统计可分隔性与超光速量子通讯不可能
张启仁
2004, 21(2): 104-106. doi: 10.11804/NuclPhysRev.21.02.104
摘要:
分析了量子力学中的空间关联与通讯的关系与差别,提出了统计可分隔性概念, 由此证明了超光速量子通讯不可能.We analyse the relation and the difference between the quantum correlation of two points in space and the communication between them. The statistical separability of two points in the space is defined and proven. From this statistical separability, we prove that the superluminal quantum communication betwcen different points is impossible. To emphasis the compatibility between the quantum theory and the relativity, we write the von Neumann equation of density operator evolution in the multitime form.
NΩ束缚态问题的研究
余友文, 张宗烨
2004, 21(2): 107-108. doi: 10.11804/NuclPhysRev.21.02.107
摘要:
从夸克反夸克通过介子场耦合的模型出发研究了(N)LST是否存在束缚态的问题. 计算表明当考虑了u(d)湮灭K*为介子的机制后, (N)LST是有可能形成结合能较大的束缚态. The structures of (N)LST systems are studied in the SU(3)quark model, in which the coupling between quarkantiquark and the meson fields are included. A resonating group method (RGM) calculation shows that (N)0212could be a bound state with considerably large binding energy, when the mechanism of u(d) annihilation to K* is considered.
组分夸克模型点评(英文)
王凡
2004, 21(2): 109-113. doi: 10.11804/NuclPhysRev.21.02.109
摘要:
以最新格点QCD和手征对称自发破缺结果为基础,对目前流行的组分夸克模型中采用的夸克囚禁方案和Goldstone玻色子-夸克耦合中存在的问题进行了讨论.The problems related to the modelling of quark confinement and Goldstone boson quark coupling in the prevailing constituent quark models are discussed
based on the lattice QCD result and the chiral symmetry spontaneous breaking
theory.



Grover量子搜索算法及改进
龙桂鲁, 李岩松, 肖丽, 屠长存, 孙扬
2004, 21(2): 114-116. doi: 10.11804/NuclPhysRev.21.02.114
摘要:
简单地介绍了量子搜索算法中的相位匹配条件、 改进的成功率为100%的量子搜索算法和量子搜索算法中的主要误差等.
We briefly introduced some of our recent work related to the phase matching condition in quantum searching algorithms and the improved Grover algorithm. When one replaces the two phase inversions in the Grover algorithm with arbitrary phase rotations, the modified algorithm usually fails in searching the marked state unless a phase matching condition is satisfied between the two phases. The Grover algorithm is not 100% in success rate, an improved Grover algorithm with zerofailure rate is given by replacing the phase inversions with angles that depends on the size of the database. Other aspects of the Grover algorithm such as the SO(3) picture of quantum searching, the dominant gate imperfections in the Grover algorithm are also mentioned.
核子质量、 半径及夸克凝聚的核物质密度依赖性
刘玉鑫
2004, 21(2): 117-120. doi: 10.11804/NuclPhysRev.21.02.117
摘要:
简要介绍核物质中核子的质量、 半径及夸克凝聚的密度依赖关系基于QCD模型和QCD有效场论研究的现状, 并具体介绍整体色对称模型(GCM)的研究结果. GCM研究表明, 在小于临界密度的情况下, 核物质中核子的质量随核物质密度的增大而减小, 核子的半径和夸克凝聚随核物质密度的增大而增大. 当达到临界密度时, 核子质量减小为零, 核子半径变为无限大, 夸克凝聚突变为零, 进而提出一个核物质中手征对称性恢复的新机制.
The status of the investigations on the nucleon mass, nucleon radius and quark condensate in the framework of QCDinspired models and QCD effective field theories is briefly reviewed. The results in the global color symmetry model (GCM) are described a little detailedly. The calculated results indicate that, before the maximal density is reached, the mass of a nucleon in nuclear
matter decreases, the radius of a nucleon and the quark condensate increase very slowly, with the increase of the nuclear matter density. As the maximal nuclear matter density is reached, the mass of the nucleon vanishes gradually. The radius becomes infinite and the quark condensate vanishes suddenly. A new mechanism for the chiral symmetry restoration in nuclear matter is proposed.
在高密度下核物质的色超导性
王凌峰, 吕晓夫
2004, 21(2): 121-126. doi: 10.11804/NuclPhysRev.21.02.121
摘要:
建立了相变热力学理论和场论的关系. 强调在量子场论中必须引进序参量场, 则相变的讨论就类似于Goldstone bosons 的产生. 如果只讨论一级相变, Goldstone bosons场就足够了; 如果要讨论二级相变, 则必须讨论一系列的场, 这些场构成一个对称群的表示. 另外, 也将这一思想用到色超导中. In this paper we built a relation between the thermodynamical theory of the phase transition and field theory. We emphasized that in the quantum field theory we have to introduce the order parameter fields. Then the discussion of the phase transition is closed to the creation of the Goldstone bosons. If we only discuss the first order transition, the Goldstone bosons fields are sufficient. If we want to discuss the second order transition, we have to discuss a set of fields that constructs a representation of a symmetry group. We also apply this concept to color superconductivity.
弹性e-d散射中氘核的张量极化t20与ρπγ耦合过程
程檀生
2004, 21(2): 127-129. doi: 10.11804/NuclPhysRev.21.02.127
摘要:
在夸克-强子混杂模型基础上,利用氘核的相对论波函数,计及冲击近似、ρπγ过程贡献和6夸克集团效应, 计算了氘核的张量极化t20. 结果表明, 当ρπγ耦合常数取正值时, t20的理论值才与新扩展的实验数据符合. Tensor polarization t20 of the deuteron is calculated on the basis of a hybrid quarkhadron model. A relativistic wave function of the deuteron is used to calculate the relativistic impulse approximation and the contribution of the ρπγ meson exchange process. Good agreement with experimental data is achieved when and only when the ρπγ coupling constant is taken as positive.
八极形变核的反射不对称壳模型描述
陈永寿
2004, 21(2): 130-136. doi: 10.11804/NuclPhysRev.21.02.130
摘要:
发展反射不对称壳模型, 描述八极形变核. 哈密尔顿量包含了四极、 八极和十六极多极力,
单极和四极对力. 壳模型空间由八极形变轴对称Nilsson势加BCS的投影基矢构成. 理论模型再现了和解释了实验八极转动带的基本特性. 理论计算很好地再现了190, 194Hg的超形变转动带实验谱, 从而为八极超形变转动带的可能的实验证据提供了理论支持.
The reflection asymmetric shell model approach has been developed for the description of octupole deformed nuclei. The Q· Q forces of quadrupole, octupole and hexadecapole as well as the monopole and quadrupole pairings are included in the Hamiltonian. The shell model space is spanned by a
selected set of the projected axial and octupole Nilsson + BSC basis. The general features of experimental octupole rotational bands can be reproduced and interpreted by the present model. The experimental superdeformed band states in 190, 194Hg are well reproduced by the present calculations, which provide theoretical support to the possible experimental evidence for the discovery of the octupole superdeformed rotational bands.

强和弱Y-Y相互作用下的奇异强子物质
宋宏秋, 苏汝铿, 鲁定辉, 钱伟良
2004, 21(2): 137-141. doi: 10.11804/NuclPhysRev.21.02.137
摘要:
把修正的夸克-介子耦合模型推广到包含奇异性的情形, 并用来研究奇异强子物质的状态方程. 从最新的6ΛΛHe双超核的实验导出的弱ΛΛ相互作用和过去采用的强ΛΛ相互作用同时被用于计算. 比较发现, 具有强Λ-Λ相互作用的系统束缚得比正常核物质要紧, 而具有弱ΛΛ相互作用的系统则比正常核物质束缚得要松得多. 无论强还是弱相互作用情况, 为了合适地描述修正的夸克介子耦合模型中超子-超子(YY)相互作用, 必须引进σ*和介子.
A modified quark meson coupling (MQMC) model is extended to include Λhyperons and Ξhyperons. The extended model is then used to study the equation of state (EOS) for strange hadronic matter. A weak ΛΛ interaction deduced from recent observation of 6ΛΛHe double hypernucleus is adopted in the calculation. The resultant EOS is compared with that deduced from a strong ΛΛ interaction. It is found that while the system with the strong ΛΛ interaction is more deeply bound than ordinary nuclear matter due to the opening of new degrees of freedom, the system with the weak ΛΛ interaction is rather loosely bound compared to the later. It is necessary to introduce the strange mesons σ*and in the MQMC model to describe properly the interaction between the hyperons in either strong or weak ΛΛ interaction case.
在RHIC的极限碎裂和Φ介子产生(英文)
萨本豪, 苏宗涤, 台安, 周代梅
2004, 21(2): 142-147. doi: 10.11804/NuclPhysRev.21.02.142
摘要:
利用强子和串级联模型LUCIAE研究了PHOBOS的极限碎裂等以及在PHIC进行的Au+Au碰撞中带电粒子多重性的经验标度规律. 对Φ介子的产生机制也通过与带电粒子多重性的比较进行类似的研究. 结果似乎表明在串级碎裂模型中带电粒子和Φ介子有共同的产生机制. 还讨论了PHOBOS经验标度规律的模型依赖性.
The PHOBOS’s limiting fragmentation etc. three empirical scaling rules for
charged multiplicity in Au+Au collisions at RHIC are investigated by a
hadron and string cascade model LUCIAE. Similar studies are performed for the meson exploring its production mechanism via comparing with the charged
multiplicity. The LUCIAE results for charged multiplicity are compatible with
PHOBOS observations. However, for the  meson the three empirical scaling
rules are either kept only or kept better in the LUCIAE calculations without
reduction mechanism of the s quark suppression extra introduced for the
strangeness in LUCIAE model. These results seem indicating a universal
production mechanism for charged particle and  meson in string
fragmentation regime. It is discussed that the PHOBOS’s empirical scaling
rules are model dependent indeed.
从流夸克质量到组分夸克质量的动力学过渡的研究
朱基珍, 卢娟, 周丽娟, 马维兴
2004, 21(2): 148-151. doi: 10.11804/NuclPhysRev.21.02.148
摘要:
在彩虹近似下用DysonSchwinger 方程研究了禁闭夸克的传播子, 得到了夸克动力学质量随动量变化的关系, 即得到了从流夸克质量到组分夸克质量的动力学过渡.
基于原子系综集体激发的量子存贮
孙昌璞, 李勇, 刘旭峰
2004, 21(2): 152-156. doi: 10.11804/NuclPhysRev.21.02.152
摘要:
近几年来,人们从理论和实验两个方面探讨了利用自由原子系综作为量子记忆体的可能性. 基于固定于格点上Λ型“原子”系综的准自旋波激发的研究, 提出了实现光子信息量子存贮的新方案. 这个方案的目标是为了克服自由原子系综量子存贮方案中存在的量子态漏损诱导退相干的致命问题. 研究过程中发现了系综型量子记忆体中隐藏动力学的对称性和其绝热暗态演化的选择定则. 为了确切地表述这个工作的意义,还扼要地介绍这个方案建立的前期关于原子系综对称集体激发的系列工作. In this article we reviews a new protocol of quantum memory based on the quasipin wave excitation of the Λ systems fixed the sites of lattice. This protocol tries to avoid the disadvantage of the quantum memory scheme based on free atom ensemble, the quantum decoherence induced by the quantum leakage of collective state. Especially,we discover a universal dynamic symmetry hidden in various ensemble based quantum storage scheme. To understand the significance of this work exactly, we also give a brief introduction to our systematical studies on collective symmetric excitons in quantum ensemble,which is the necessary to propose the present scheme for quantum memory.
单胶子交换和单π交换夸克模型中核子负宇称共振态的电磁跃迁振幅(英文)
董宇兵, 何军
2004, 21(2): 157-158. doi: 10.11804/NuclPhysRev.21.02.157
摘要:
分别利用单胶子交换和单π交换夸克模型计算了核子负宇称激发态的电磁跃迁振幅,讨论了两个模型所给出的不同的组态混合角. 结果表明, 单胶子交换模型所给出的重子波函数比单π交换夸克模型的波函数更为合理.Electromagnetic transition amplitudes of negative parity resonances are calculated based on onepion exchange (OPE) model and one gluon exchange (OGE) model, respectively. The configuration mixing caused by the hyperfine interactions of the two models is discussed. Calculated results for the
amplitudes indicate that baryon wave functions of OGE are more reasonable
than those of OPE.
三轴形变对102Rh旋称反转的影响
郑仁蓉, 杨盈春, 陆祺, 朱顺泉
2004, 21(2): 159-161. doi: 10.11804/NuclPhysRev.21.02.159
摘要:
将两准粒子加轴对称转子模型扩展到三轴形变, 对奇奇核102Rh的旋称反转进行了研究和分析, 结果表明, 可能的旋称反转机制 (即低K 空间np相互作用和科氏力的相互竞争), 对于A=100质量区奇奇核也是适用的, 三轴形变可以明显地改进能谱的振荡特性.
The model of an axially symmetric rotor plus two quasiparticles for the Signature Inversion (SI) in oddodd nuclei is generalized to the triaxial deformation. The calculation of the odd  odd nucleus 102Rh shows that the possible SI mechanism (i. e., the competition between the np interaction and the coriolis force in low K space) is also appropriate for oddodd nuclei in the A=100 region. A triaxial shape can improve the vibration property of the rotational spectra remarkably.
孤立纯光子系统与背景辐射
张邦固
2004, 21(2): 162-164. doi: 10.11804/NuclPhysRev.21.02.162
摘要:
从能量角度论述了孤立纯光子系统是不稳定的. 它与观测到的宇宙微波背景辐射的光子平衡态是截然不同的. 所以, 正在膨胀着的宇宙不会来自一团“纯能量”.
The unstability of any isolated pure photon system is indicated from the angle of energy. The nature of this system is completely different from the one of an equilibrium state of photons, which is just the cosmic microwave background radiation observed. Therefore, our expanding universe can not come from a group of pure energy.
J/Ψ衰变的Roper共振态结构的研究
平荣刚
2004, 21(2): 165-169. doi: 10.11804/NuclPhysRev.21.02.165
摘要:
通过J/Ψ→p, p*, N**衰变,研究了Roper共振态的混杂态结构对衰变角分布和分支比的影响. 计算结果表明,如果Roper共振态为纯混杂态,那么J/Ψ→p*, N**的角分布几乎相等, 而J/Ψ衰变到混杂态的衰变宽度还不到J/Ψ→p 的1%, 给出了Γ(J/Ψ→ N* )/Γ(J/Ψ→p)和Γ(J/Ψ→ N**)/Γ(J/Ψ→ p)随混合参数的变化关系, 并讨论了在J/Ψ衰变中研究Roper混杂态结构的可能性.
The structure of Roper resonance is studied as hybrid states through decays J/Ψ→p*, N** by calculating the angular distributions and decay widths. The results show that the angular distribution parameters for decays J/Ψ→p*, N** are almost equal if the Roper is identified as a pure hybrid state, while their decay width are less the 1% of that for the decay J/Ψ→p, and the variance of the ratio Γ(J/Ψ→N*p)/Γ(J/Ψ→p) and Γ(J/Ψ→N**)/ Γ(J/Ψ→p) with the mixing parameter are presented,and also the scheme to identify the Roper structure in J/Ψ decays is discussed.
奇特核和超核中的晕现象
孟杰, 吕洪凤, 张双全, 周善贵
2004, 21(2): 170-173. doi: 10.11804/NuclPhysRev.21.02.170
摘要:
讨论奇特核和超核中的各种晕现象. 根据密度相关零程对力的相对论连续谱HartreeBogoliubov理论给出的计算结果, 预言了中子滴线附近的Ca原子核中可能存在着巨晕, 并简要介绍了O, Ni, Zr, Sn和Pb等一些质子幻数核从质子滴线到中子滴线之间的原子核基态性质. 随后给出超核内的晕现象研究, 如Ca超核内的中子晕和153ΛC内的单Λ超子晕.
Halos in the relativistic continuum Hartree Bogoliubov (RCHB) theory are investigated,including giant halo in the evenN Ca isotope near neutron drip line,halos in hypernuclei and the hyperon halos in 153ΛC.
重整化群与临界现象
纪青
2004, 21(2): 174-176. doi: 10.11804/NuclPhysRev.21.02.174
摘要:
介绍了用重整化群方法描述临界现象的基本思路和做法. 指出重整化群方法确实抓住了临界现象的最重要的物理特征——自相似性, 并在此基础之上建立了一套切实可行的求解方案. The basic clue and the main steps of renormalization group method used for the description of critical phenomena is introduced. It is pointed out that this method really reflects the most important physical features of critical phenomena, i.e. self similarity,and set up a practical solving method from it. This way of setting up a theory according to the features of the physical system is really a good lesson for today’s physicists.

分子马达动力学
赵同军, 李微, 韩英荣, 卓益忠
2004, 21(2): 177-179. doi: 10.11804/NuclPhysRev.21.02.177
摘要:
分子马达是一类将化学能转化为机械能的微小机器. 对二维模型的研究表明, 非保守力在体系与外界能量交换中发挥重要作用. 四态模型较好地反映了马达力学化学过程的各个状态及相应的构象变化. Motor protein is a kind of small machines that convert chemical energy to mechanical works. It is revealed from the study of the twodimensional model that the non conservative impulsive force plays a significant role in the exchanging process of energy. A four state model characterizing the coupling of mechanical and chemical processes of molecular motor is also discussed.
强激光场中氘团簇双重膨胀引发核聚变
安伟科, 邱锡钧, 蒋懿, 朱志远
2004, 21(2): 180-182. doi: 10.11804/NuclPhysRev.21.02.180
摘要:
在超强fs激光与氘团簇的相互作用中, 分析了可以引发核聚变的高能氘核产生的原因,提出了团簇双重膨胀的机制,计算了氘核动能及团簇解体的时间, 为选取合适的激光脉冲宽度参数提供参考. Considering the Coulomb explosion induced by the interaction of a deuterium cluster target with ultra intensity femtosecond laser,the causation which generate energetic deuterium nuclei for the fusion has been analyzed. The mechanism for the dual explosion of deuterium cluster is proposed, and hence the velocity of deuterium nuclei and the expansion time of deuterium ion clusters have been estimated.