2005年 第22卷 第4期
证明频率为v的辐射引起的量子跃迁中，跃迁系统始末两态能量差不必是hv的整数倍。跃迁的玻尔条件和光电效应的爱因斯坦定律都是微扰近似的结果，在强激光引起的跃迁中不成立。We prove that in the quantum transition of a system induced by the radiation of frequency v, the energy difference between the initial and the final states of the system is not necessarily being an integer multiple of hv. The Bohr condition for quantum transitions and the Einstein law for photo-electric effects are approximate results of perturbation. They are violated in the transitions induced by intense lasers.
简要回顾了生物学与物理学之间的紧密关系，其中包括人工神经网络的经典物理模型和脑的某些量子理论；概要综述了细胞骨架微管的结构和生物功能及有关近期理论研究。注意到微声是细胞和神经元中重要的组成和功能单元，进而以较大篇幅介绍了近期关于微管的理论研究工作，特别是基于量子场论中两能级系统的赝自旋模型，对微管管壁上电子的动力学行为作了较深入的探讨；此外，基于量子场论，对微管中的水分子系统可能存在微波受激辐射也作了阐述。The present paper briefly reviews the relationship between biology and physics, especially including the classical physics models for the artificial neuron networks, some quantum theories for brains, and simply describes the structures and functions of cytoskeletal microtubules （MTs） in cells and some recent theoretical studies on MTs.Noting MTs are the important components and function units in cells and neurons, furthermore, the paper lays emphasis on our recent theoretical work on MTs. Particularly, based on the pseudo-spin quantum theory, the dynamic behavior of electrons on the MT wall has been discussed in some detail. Based on the quantum field theory, it has been described that the maser radiation might exist in the water molecular system within the MT.
简单介绍了兰州-北京-吉森合作组对合成超重核的重离子反应进行的初步研究。研究的重点是熔合阶段的反应机制。在原有双核模型的基础上做了一些改进，把耗散相对运动过程与核子转移过程耦合起来，从更微观的角度来描写双核系统向全熔合复合核的演化。在双核过程中的每一步求解主方程，不对驱动势做谐振子近似。同时，还探讨了原子核形变与相对取向对驱动势的影响，存活几率与复合核蒸发中子的奇偶效应，以及入射道中原子核非弹性激发对俘获截面的影响等。In recent years, the Lanzou-Beijing-Giessen collaboration has studied the heavy ion reactions which are lead to the formation of super-heavy nuclei. The study emphases the mechanism of the fusion stage of the reactions. Based on the so called Di-nuclear System Model, some improvements have been made. The main points are the coupling of the dissipation of relative motion energy, angular momentum with nucleon transfer, and solving the Master equation in every step of the nucleon transfer with exact driving potentials, in order to describe the evolution of the system more microscopically. At the same time, we also discussed the effects of nuclear deformation and their relative orientation on the driving potentials, and studied the survive probability of the compound nuclei and its old-even effects, as well as the influence of inelastic excitations of nuclei in entrance channels to the capture cross sections.
反射不对称壳模型推广到包括轴对称破缺。在这一发展中，壳模型空间由三轴形变的多准粒子基所构建，实现了对旋称反转、手征带和摇摆带的统一的壳模型描述。在壳模型框架下，三轴性的引入，严格的三维投影和直到六准粒子的组态混合，使该理论可以在一个新的水平上研究高速转动三轴形变核中的物理现象。The Reflection Asymmetric Shell Model has been generated to include the axial symmetry break. In this new development, the shell model space is spanned by the triaxially-deformed multi-quasi-particle basis. A unified shell model description of the signature inversion, chiral and wobbling bands can be achieved. In the frame work of shell model, the inclusion of the triaxiality, the exact three dimensional projection and up to six quasiparticle configuration mixing make the theory powerful to study the phenomena in highly rotating triaxial nuclei at a new level.
讨论了通过重核碰撞形成的复合体系破裂产生超重核的问题。评述了两种主要的理论模型：即早期发展的在碎化理论框架下的量子涨落理论和本课题组尝试发展的微观输运理论模型。概括阐述了微观输运理论研究^197Au＋^197Au，^238U＋^238U和^244Pu＋^244Pu等反应的主要结果，即反应中产生的超重碎块的几率与入射能的关系，复合体系和超重碎块的衰变机制以及所形成的超重碎块的结合能和形状的分布。In this paper, the possibility of producing superheavy fragments through composite system breaking up in massive nuclear reactions is investigated. Two main theoretical models, which are the quantum fluctuations with in the fragmentation theory developed at 1980＇s and improved quantum molecular dynamics model developed recently by our group, are briefly reviewed. The dependence of the production probability of superheavy fragments on the incident energy, the decay mechanism of composite system and superheavy fragments, and the distribution of binding energy of Superheavy fragments are discussed for reactions of ^244Pu＋^244Pu, ^238U＋^238U, 197Au＋^197Au based on the improved quantum molecular dynamics model.
评述和分析了磁约束核聚变理论研究、数值模拟和实验研究等方面最近几年共同关心的一个重要问题——寻找托卡马克等离子体湍流中的带状剪切流（zonal flows）。简要介绍了作者最近对电阻性-重力模湍流中的带状剪切流的研究结果。 Progress of the research on the zonal flows in tokamak plasma turbulence is surveyed, especially it is reviewed that the zonal flows observed in the experiments and numerical simulations on atmosphere turbulence and ocean turbulence and the discovery of H-mode in tokamak experiments how lead the researchers in magnetic confinement fusion community to find out the existence of the zonal flow in tokamak plasma turbulence and subsequently give the experimental verification of its existence. Finally, the results of our research on zonal flow generation and evolution in resistive-g mode turbulence are presented in brief.
简要介绍了JLab的一般情况、JLab高性能加速器CEBAF（Continue Electron Beam Accelerator Facility）和3个实验大厅的主要实验设备。着重介绍了CEBAF的连续束流与实验大厅的高密靶及高精度谱仪结合所得到的高精度实验结果，介绍了JLab实验室要解决的根本问题、相应的物理课题以及中国组正在参与数据分析和正在做的实验。最后简要介绍了CEBAF升级至12 GeV及其带来新的研究机会和新的物理课题，以及中国组与JLab的合作情况。The general situation of JLab is briefly introduced. The accelerator CEBAF with high quality and the equipments in the three Halls are described. The experimental results with high accuracies, which were obtained by using continue beam with high energy resolution, and high density target and high resolution spectrometers in the halls, are presented with two examples. The basic physics problems which JLab intends to solve, and the programs which JLab completed and is going to do, are stated. The programs which China group is cooperating with other groups are emphasized. The energy escalation for CEBAF will bring new opportunities for scientific researches.
总结了利用核子内的奇异夸克反奇异夸克不对称性来解释NuTeV反常的工作，表明奇异夸克反奇异夸克不对称性可作为解释NuTeV反常的一种合理机制，也说明了NuTeV反常现象也可能是对奇异夸克反奇异夸克不对称性的一种支持。This talk summarized the results of using strange quark-antistrage quark asymmetry of the nucleon to explain the NuTeV anomaly. It is shown that asymmetric strange quark-antistrage quark distributions may be a reasonable explanation for the NuTeV defect. On the other side, the NuTeV anomaly could be the evidence for the existence of asymmetric strange-antistrange quark distributions.
讨论了原子核α衰变和结团放射性的一个新的结团模型：密度依赖的结团模型（DDCM）。DDCM基于微观真实的核势和库仑势，可以在统一的框架下计算原子核的各种衰变模式的半衰期。通过对原子核α衰变和结团放射性的系统计算，发现DDCM能够精确给出原子核α衰变和结团放射性的半衰期，理论值和实验值的偏差一般在3倍以内。这表明密度依赖的结团模型具有很好的适用性并可以为将来的实验提供较准确的预言。We have discussed a new cluster model of α-decay and cluster radioactivity： the density-dependent cluster model （DDCM）, which is based on the microscopic nuclear potential and Coulomb potential. DDCM can give accurate theoretical half-lives for various decays of nuclei in a unified framework. Through a systematical calculation of half-lives of α-decay and cluster radioactivity, we find that the deviation between DDCM and experiment is usually less than a factor of 3. This good agreement shows that the density-dependent cluster model can further provide reliable predictions for future experiments.
对国内外核物理发展现状、前沿进行了简要分析和概括，对我国核物理发展优先资助领域提出了自己的一些看法和建议。A brief review is given on the frontiers of nuclear physics research. Some personal opinions and suggestions to the NSFC on the fields to have priority for support are presented.
讨论了密度矩阵的不同定义。建议使用完全密度矩阵、压缩密度矩阵和约化密度矩阵分别描写一个封闭量子体系的、一个系综中平均分子的和一个复合体系中的一个子系统的密度矩阵。强调这与现在人们认为的具有相同压缩密度矩阵的系综是完全等价的结论完全不同，具有相同压缩密度矩阵但是成分不同的系综可以通过系综整体测量来区别。作为一个应用，现在认为现有的核磁共振量子计算中没有纠缠的结论是没有根据的。Density matrix is one important tool in quantum mechanics, and it has very broad applications. However there are different definitions about the density matrix, and they describe quite different systems. There has been some misunderstanding about the density matrix in the community, and these misunderstandings hinder the right application of the density matrix. In this article, we discuss the different definitions of density matrix. We suggest to use the full density matrix, compressed density matrix and the reduced density matrix to describe the state of a complete quantum system, the state of an averaged particle in an ensemble and the state of part of a composite system. We stress that contrary to the wide accepted understanding that ensembles with the same compressed density matrix are physically indistinguishable, they are distinguishable through the so-called ensemble measurement. As an application, we suggest that the present conclusion that the present-day nuclear magnetic resonance quantum computation does not have quantum entanglement is groundless.
简要回顾原子核形状相变研究的现状，并将相干态理论与角动量投影方法相结合，在不区分质子玻色子和中子玻色子的相互作用玻色子模型（IBM-1）框架下，对角动量驱动的轴对称情况下的具有U（5）、SU（3）对称性以及两种对称性之间过渡区的原子核的形状相变进行了具体研究。We review the status of the research of nuclear shape phase transitions in this paper. Meanwhile, by taking the coherent state theory and angular momentum projection method, we study the shape phase transitions of axially symmetric even-even nuclei with U（5） symmetry, SU（3） symmetry and those in the transitional region of the two symmetries in the framework of Interacting Boson Model-1 （IBM-1）, which does not distinguish the proton bosons from neutron bosons.
根据有关分子马达的重要实验结果，明确指出分子马达的运动过程是一个化学、电学、力学3种过程互相耦合的生物学过程。主要介绍有关kinesin的力产生机制的研究现状以及在这方面的研究。On the basis of the important experimental results of molecular motors, it was polnted out that the moving process of molecular motors is a coupling biological process of chemical-electrical-mechanical processes. This clever mechanism of energy conversion on the molecular level with several processes coupled together had never been observed before. The understanding of this new mechanism is an important step towards the understanding of life and an important content of what we can learn from life. We introduced here the status of the investigations on the mechanism for the force generation of kinesin and the studies of the authors in this field
考虑一个处于非Ohmic环境下的系统定向通过一个倒谐振子势鞍点的输运过程，给出了通过几率的解析式。结果表明在欠扩散情况下，时间有关的通过几率出现一个很强的超前峰和回流，这可能有助于理解重核熔合系统的激发函数随质心能量的慢增长机制。Directional transport of a particle in a non-Ohmic environment passing over the saddle point of a potential is considered and the analytical expression of the passing probability is obtained. Our results has shown that both overshooting and backflow are observed in the case of subdiffusion. This is a possible for understanding slow increasing of the fusion probability with the center-of-mass energy.
讨论了重离子辐照生物中核碎裂效应，给出与此相关的核碎裂研究现状和进展。The effect of nuclear fragmentation discussed. The status and perspectives of this data. in the topic interactions of heavy ions with biological are presented based On calculations and molecules is experimental.
采用手征σ模型描述核多体系统，考虑真空极化的影响，首先由核物质的饱和性质确定模型参数，进一步研究了强子性质在核介质中的变化。手征σ模型的研究结果给出，核子和ω介子的有效质量随核物质密度的增大而减小，但σ介子的有效质量随密度的增大而增大。这些结果与不满足手征对称性的Walecka模型结果进行了比较。计算中采用的重整化方法会对结果有一定的影响。The modification of hadron masses in nuclear medium is studied by using the chiral sigma model, which is extended to generate the omega meson mass by the sigma condensation in the vacuum in the same way as the nucleon mass. The chiral sigma model provides proper equilibrium properties of nuclear matter. It is shown that the effective masses of both nucleons and omega mesons decrease in nuclear medium, while the effective mass of sigma mesons increases at finite density in the chiral sigma model. The resuits obtained in the chiral sigma model are compared with those obtained in the Walecka model, which includes sigma and omega mesons in a non-chiral fashion.
讨论了Casten的NpNn系统学、壳模型的配对近似方法应用及多体系统的某些固有性质，主要侧重于这3个问题研究的物理基础和意义。I would like to discuss low-lying systematics of NnNp suggested by Rick Casten, Nucleon-pair approximation of the nuclear shell model and its applications, and intrinsic properties of many-body systems in the presence of random interactions. I shall emphasize on backgrounds and perspectives of these problems, and summarize our basic understanding on these problems, after many efforts made by my collaborators and me.
简要地介绍了量子安全直接通信的必要条件，初步介绍了两个量子安全直接通信模型，即Two-Step和Quantum-One-Time-Pad模型。 The requirements of quantum secure direct communication （QSDC） are briefly introduced. Two QSDC schemes i. e. , the Two-Step QSDC scheme and the Quantum-One-Time-Pad QSDC scheme, are discussed in brief.
根据实际天文观测论述了膨胀着的宇宙系统的时间可以与空间分开来讨论；宇宙的空间是平直的。在宇宙质心坐标系中，由背景辐射温度、宇宙密度和宇宙半径（最远星系的距离）3个观测数据计算了宇宙这个引力系统的总能量，结果表明系统是一个引力束缚态，将来会收缩。在均匀分布的初始条件下计算了收缩过程，这是同步自由落体过程。在宇宙的膨胀过程与其收缩过程对称的假设之下，建立膨胀时间与背景辐射温度的一对一的对应关系。According to astronomical observation we point out that the time of our expanding cosmic system can be discussed separating from the space. And the space in our universe is flat. In the cosmic center-of-mass frame（CCF）, based on the temperature of CMBR, the cosmic density and the cosmic radii, the distance of the farmost galaxy, the total energy of our universe asa gravitation system has been calculated. It shows that our universe is in a gravitational bound state, and it will contract. In CCF the contracting progress is a synchronized freely falling body under initial condition of uniform distribution. Uder assumption of the symmetry of cosmic expanding and contracting progresses, th one-to-one correspondence of the expanding time to the temperature of CMBR can be obtained.
随机数的产生和概率分布的随机抽样方法，是蒙特卡罗方法的两个最基本的问题。对这两个问题的处理目前仍然因循60年前蒙特卡罗方法诞生初期的技术途径，因此长期受一些无法彻底解决的问题所困扰，同时也面临一些新问题的挑战。分析了上述问题，分别对随机数的产生和任意分布的抽样方法给出了新的技术解决途径。The producation of random number and the sampling of random distribution are two foundational problems in Monte Carlo Mothed. In this paper, we carry out some new ways to treat the problems.
介绍了在DNA辐射损伤以及相关生物、物理、化学问题的一些研究工作。重点是径迹结构、DNA双链断裂和细胞学终点的关系。P53-Mdm2负反馈回路在DNA损伤的细胞响应方面起重要作用，用一个简单的模型研究了P53-Mdm2负反馈回路相互作用的动力学行为。Some of recent works are presented on radiation induced DNA damage being carried out at China Institute of Atomic Energy （CIAE） and related bio-chemi-physical problems. Emphasis is placed on track structure and its relation to the cell end-point, and a simple model proposed to study the dynamical behavior of P53-Mdm2 interaction which plays pivotal role in cellular response to DNA damage.
简要介绍和评述了近几年来中高能核物理中一些受关注的问题，重点介绍了核子电磁形状因子和K^-介子与原子核相互作用势强度问题。 Several problems in intermediate and high energy nuclear physics have attracted considerable attention in these years： （1） Nucleon electromagnetic form factors. There is a systematic difference between the recently measured data from high energy polarized electron-nucleon scattering experiments and the previous Rosenbluth results. （2） The strength of K^- nucleus optical potentials. It varies qualitatively from different analyyses on K^- nucleus interactions. In this paper, the above problems are discussed and reviewed briefly.
微管管壁上的原丝纤维可以描述成各项异性的二维赝自旋模型，其最小重复单元是三角形状的。在这个模型中存在三种不同的“自旋-自旋”相互作用。而每一维上的自由电子可以看作是赝自旋模型。那么，微管壁上的量子信息传递就可以用Lylod提出的激光控制量子计算的模型来解释。Microtubule （MT） is described as an anisotropic two-dimensional pseudo-spin model on a triangular lattice, in which there are three different ＂spin-spin＂ interactions. The mobile electron in each lattice site is described based on the pseudo-spin model. Then, the processing of quantum information in the MT wall is presented by virtue of the scheme of driving quantum computer in sequence of laser pulse developed by Lloyd.
Quantum coherence effects in degenerate cascade three-level atom subject to magnetic field are investigated. One-photon EIT, two-photon EIT and two-photon EIA are obtained, due to the coherence between the drive Rabi frequency and Zeeman splitting.
结合钾离子通道的三维精细结构，从第一性原理出发，在充分考虑电子相互作用的基础上，采用密度泛函方法计算得到了钾通道的位能曲线；以此作为钾通道布朗动力学模型的力场参数，应用布朗动力学方法研究了钾离子通道的动力学特征，得到了一些有益的结果。In the paper, based on the first principle and the X-ray structure of the potassium ion channel, the potential curve is calculated by the density functional theory. And forced by the potential, the dynamical properties of K channels are also studied.
采用经典分子动力学方法和TLHT势模型，研究了He注入不同管壁缺陷的单壁纳米碳管（SWNCT）的动力学过程，发现对应不同入射能量，He有4种典型的运动模式。管壁缺陷的尺寸对He在SWNCT中的吸附存储行为有很大影响。 Based on the classical molecular processes of He atom into SWCNT with wall dynamics method and TLHT potential model, the injection defects of different radius are studied. The calculated results indicate that there are four typical moving patterns of He atom with different injective energy and the size of wall defects make a great difference to the absorption and storage behavior of He into SWNT.
简要介绍和评述了色味连锁物质的稳定态及其相变，指出高密强相互作用物质由于夸克配对出现了一些奇异相。重点介绍色味连锁（CFL）物质及其中的Goldstone-mode凝聚现象。在考虑奇异数对应化学势μs≠0的情况下，CFL物质中K^0和K^-0都可能发生凝聚。随着重子数密度的增高，强作用物质呈现出丰富相结构，在核物质相与CFL相之间可能存在其它相，但最简单的可能相变过程是直接从核物质相变为CFL物质。这种相变可有两种过程，即两相间仅存在一个极小界面或出现两相混合区域。另外还重点讨论了K^-介子凝聚对相变的影响。Quark matter at high density has a rich phase structure. Goidstone-mode may condense in the color-flavor-locked （CFL） phase matter. We review the stability of CFL phase and its phase transition, as well as the effect of nonzero strangeness chemical potential on the CFL phase of dense quark matter. It is pointed out that, depending on the value of μs, both K^0 and K^-0 may condense in the CFL matter. As a function of quark chemical potential, other phases may intervene between the nuclear-matter and CFL phase. The simplest possibility, however, is a transition between nuclear and CFL matter. Such a transition could occur either at a single sharp interface or through a mixed phase region. The effect of discontinuous K^- meson condensation on the phase transition is also discussed. [
用相对论平均场下的手征强子模型研究了前中子星内K^-凝聚和超子的生成。结果显示，前中子星内的中微子束缚使得出现K^-凝聚的临界密度推迟到更高的重子密度，而K^-0凝聚无法出现。同时中微子束缚使得前中子星的状态方程变硬，从而前中子星的最大质量变大。如果考虑超子，前中子星内无法出现K^-凝聚，同时系统的状态方程变软（与不含超子的情况相比），从而对应前中子星的最大质量变小。A chiral hadronic model is extended to investigate antikaon condensation and hyperons production of protoneutron stars. Our results show that neutrino trapping makes the critical density of K^- condensation delay to higher density and K^-0 condensation not occur. Meanwhile, the equation of state （EOS） of （proto）neutron star matter considering neutrino trapping is stiffer than the case without neutrino trapping. Therefore the maximum masses of rotoneutron stars with neutrino trapping are larger than those without neutrino trapping. If hyperons are considered, antikaon condensation does not appear in （proto） neutron stars. Meanwhile, the corresponding EOS becomes much softer, and the maximum masses of （proto）neutron stars are smaller than those without hyprons.
利用SD对壳模型讨论了偶偶Mo核低激发谱的集体性质。发现当SD对按照如下方法来确定，即对于两核子体系，通过对角化表面δ相互作用哈氏量，将SD对取为01^＋态和21^＋态，该模型可以合理的描述偶偶Mo核低激发态的集体性质。The SD-pair shell model was applied to study the even-even^94 Mo-^100 Mo. It is found that with the SD pair determined as 01^＋ and 21^＋ states of a two-valence-nucleon system with a Hamiltonian, which contains the single particle energy term and the Surface-Delta interaction （SDI） between like nucleons, the collectivity of low-lying states can be described reasonably.
基于从头计算方法和半经验势分子动力学，通过计算尿嘧啶分子及其水合尿嘧啶分子运动轨迹的速度自关联函数的傅立叶变换，给出了这些分子的振动频率。通过求解Hessian矩阵，鉴别出这些分子每一个振动频率的振动模式。对孤立的尿嘧啶分子，计算结果能够和实验数据符合。对水合尿嘧啶分子中，尿嘧啶分子的结构和振动频率的改变做了讨论。Based on an ab initio calculation and a semiempirical method, the structural and vibrational frequencies of Uracil and hydrated Uracil are studied by using the Fourier transform of velocity autocorrelation function of trajectories of molecular dynamics simulations. The finite difference harmonic method is also used to assign the vibrational frequency of each mode. It is found the calculation frequencies are in good agreement with the experiment data. The structural and vibrational frequencies of Uracil in hydrated form is discussed.
从基本理论出发，导出并求解了含有相对论修正的K^-介子与质子的两体薛定谔方程。其解可看作有统计解释的波函数。计算了K^p的散射长度，结果表明相对论效应是很明显的。A two-body equation of the kaon-proton system with relativistic correction is derived and solved. The solution can be considered as a wave function with the probability interpretation. The scattering lengths are calculated, and the numerical result shows that the relativistic effect is apparent.