2004年 第21卷 第2期
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 FadeevNiemi 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.
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 neutronproton 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 isospindependent quantum molecular dynamics model show that the degree of isospin fractionation is sensitive to the neutronproton ratio of colliding system. In particular， the degree of isospin fractionation sensitively depends on the symmetry potential and weakly on the inmedium nucleonnucleon cross section for the neutronrich 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.
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 particlehole 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.
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 Npole 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.
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 multitime form.
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 quarkantiquark 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.
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
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 zerofailure 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.
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 QCDinspired 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.
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.
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 quarkhadron 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.
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 superdeformed 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 superdeformed rotational bands.
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ΛΛ相互作用和过去采用的强ΛΛ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ΛΛ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（YY）相互作用， 必须引进σ*和介子.
A modified quark meson coupling (MQMC) model is extended to include Λhyperons and Ξhyperons. The extended model is then used to study the equation of state (EOS) for strange hadronic matter. A weak ΛΛ 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 ΛΛ 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 ΛΛ 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.
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.
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 quasipin 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.
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 onepion 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.
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np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 quasiparticles for the Signature Inversion (SI) in oddodd 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 np interaction and the coriolis force in low K space) is also appropriate for oddodd nuclei in the A=100 region. A triaxial shape can improve the vibration property of the rotational spectra remarkably.
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.
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.
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HartreeBogoliubov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 evenN Ca isotope near neutron drip line，halos in hypernuclei and the hyperon halos in 153ΛC.
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 twodimensional 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.
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.