IBM-Ⅱ中的有效玻色子数

通过简单的半经验方法,本文给出在Z=40、64子壳附近的有效质子玻色子数,提出在SU(3)极限下存在质子玻色子和中子玻色子的饱和.用此可解释稀土区偶偶核中B(E2)、B(M1)的强饱和性和关联性.并把本文的结果与微观计算的有效玻色子数作了比较,两者是一致的.     

IBM–2有效玻色子数和它在系统学中的应用

总结并讨论了中重核区域偶偶核IBM-2有效玻色子数随质子数和中子数变化的情况,并利用这一结果给出稀土区和锕系区偶偶核随变化的系统学结果,注意到这两个区域随变化的特点,并给以定性解释.此外,本文还采用有效玻色子数的概念,对锕系区的B(M1)系统学性质作了预言.     

IBM－2有效玻色子数和它在系统学中的应用

总结并讨论了中重核区域偶偶核ＩＢＭ－２有效玻色子数随质子数和中子数变化的情况，并利用这一结果给出稀土区和锕系区偶偶核随变化的系统学结果，注意到这两个区域随变化的特点，并给以定性解释．此外，本文还采用有效玻色子数的概念，对锕系区的Ｂ（Ｍ１）系统学性质作了预言．     

SD对壳模型与质子中子相互作用玻色子模型

在SD对壳模型理论框架下, 讨论了相互作用玻色子模型下U(5), SO(6)以及SU(3)的经典极限谱. 结果发现SD对壳模型可以很好地再现相互作用玻色子模型中的三种极限谱.     

sdgIBM微观理论方案中g玻色子的引入及其性质

介绍sdgIBM微观理论方案中g玻色子的引入过程,讨论了g玻色子的集体性,g玻色子受微观参数的影响以及和sdIBM的关系.     

相互作用玻色子模型中相变特征量的玻色子数N依赖行为

研究了相互作用玻色子模型中各种对相变比较敏感的特征量相对于总玻色子数N的依赖行为. 通过比较这些特征量在U(5)-SU(3)过渡区以及U(5)-O(6)过渡区在不同N情况下的临界行为, 发现BE(2)比值B(E2;4₁→2₁)/B(E2};2₁→0₁)和B(E2;0₂→2₁)/B(E2;2₁→0₁)等可以作为完全区分一级相变和二级相变的有效序参量.     

动力学对称性研究的拓扑途径——互作用玻色子模型中的应用示例

运用拓扑观点对IBM系统动力学对称性破坏的过程进行了研究,着重揭示了与能级免交叉联系的奇异行为及其根源.它实际上是动力学映射的不稳定不动点所导致的结果.越过不稳定不动点后,为了给出连续映射,就必须涉及能级的置换操作,因而呈现出能级免交叉的现象,并合映射不再能表示为动力学群生成元的函数,于是动力学对称性局域地实质性地受到了破坏.     

代与额外Z0玻色子数的关系

三代标准模型的费米子不可能与一个额外的Z⁰玻色子在一个大统一模型中.包括三代费米的最小的大统一模型将包括两个额外Z⁰玻色子Georgi的关于重Dirac费米子的议论得到一个实现方式,这些就是新增加的费米子(不是bizarre的).Frampton的SU(9)与SU(7)模型在现有标度下的费米子是相同的.在这个破缺方式下质子衰变的困难可解决.     

三玻色子核的核谱研究

在相互作用玻色子模型的基础上,用玻色子表面δ力作为玻色子之间的有效相互作用,计算了一些三玻色子核的核谱,同时也计算了E2约化跃迁几率,结果令人满意.表明这种模型是成功的.     

有限玻色子系统中的激发态量子相变

为了探讨原子核系统中存在激发态量子相变的可能性,在相互作用玻色子模型框架下对有限玻色子系统中的激发态量子相变现象进行唯象分析,特别是针对角动量和有限N效应如何影响U（5）-SU（3）和SU（3）-O（6）过渡区中的激发态量子相变行为进行了系统研究。结果表明,低角动量振动谱中的激发态量子相变特征在现实玻色子数情况下可以很好地保持,但随着角动量增加相变特征逐渐消失。In this work, a phenomenological analysis of the excited-state quantum phase transitions (ESQPTs) in the finite-N boson system has been carried out within the interacting boson model in order to reveal the possibility of finding ESQPTs in nuclear systems. Particularly, the angular momentum and finite-N effects on the ESQPTs in the U(5)-SU(3) and SU(3)-O(6) transitional regions have been systematically investigated. The results indicate that the main features of ESQPTs can be well preserved even at a realistic boson number for small angular momentum but will gradually disappear as the angular momentum increases.     

Evolution of order and chaos across a first-order quantum phase transition

We study the evolution of the dynamics across a generic first-order quantum phase transition in an interacting boson model of nuclei. The dynamics inside the phase coexistence region exhibits a very simple pattern. A classical analysis reveals a robustly regular dynamics confined to the deformed region and well separated from a chaotic dynamics ascribed to the spherical region. A quantum analysis discloses regular bands of states in the deformed region, which persist to energies well above the phase-separating barrier, in the face of a complicated environment. The impact of kinetic collective rotational terms on this intricate interplay of order and chaos is investigated.     

推导赝标Goldstone玻色子有效拉氏量

从QCD出发,未作近似推导出了赝标量Goldstone玻色子的有效手征拉氏量(ECL)理论.并以QCD中格林函数的形式给出了直到p⁴阶的ECL的系数的定义.     

First-order quantum phase transitions: Test ground for emergent chaoticity,regularity and persisting symmetries

We present a comprehensive analysis of the emerging order and chaos and enduring symmetries, accompanying a generic (high-barrier) first-order quantum phase transition (QPT). The interacting boson model Hamiltonian employed, describes a QPT between spherical and deformed shapes, associated with its U(5) and SU(3) dynamical symmetry limits. A classical analysis of the intrinsic dynamics reveals a rich but simply-divided phase space structure with a Hénon–Heiles type of chaotic dynamics ascribed to the spherical minimum and a robustly regular dynamics ascribed to the deformed minimum. The simple pattern of mixed but well-separated dynamics persists in the coexistence region and traces the crossing of the two minima in the Landau potential. A quantum analysis discloses a number of regular low-energy U(5)-like multiplets in the spherical region, and regular SU(3)-like rotational bands extending to high energies and angular momenta, in the deformed region. These two kinds of regular subsets of states retain their identity amidst a complicated environment of other states and both occur in the coexistence region. A symmetry analysis of their wave functions shows that they are associated with partial U(5) dynamical symmetry (PDS) and SU(3) quasi-dynamical symmetry (QDS), respectively. The pattern of mixed but well-separated dynamics and the PDS or QDS characterization of the remaining regularity, appear to be robust throughout the QPT. Effects of kinetic collective rotational terms, which may disrupt this simple pattern, are considered.     

q类似玻色算符的逆算符及其应用

在q类似Fock空间中引入了q类似玻色算符的逆算利用的性质,构造了增光子相干态的q形变形式并讨论其完备性关系.     

柱面球差透镜聚焦部分相干光束的焦移

通过定义聚焦光束的等效菲涅耳数,研究了部分相干光经柱面球差透镜聚焦后的轴上光强分布,得到了相对焦移的简单公式,即相对焦移反比于等效菲涅耳数的平方.结果表明,这种基于等效菲涅耳数的计算聚焦光学系统的焦移方法是计算部分相干光束经球差透镜聚焦相对焦移简单且有效方法.还讨论了一种特殊等效菲涅耳数为纯虚数情况.结果证明,在这种情况下,该相对焦移简单公式仍然有效.     

142-164Dy核的低能谱和电磁跃迁的相互作用玻色子模型

采用IBM模型研究了^142-164Dy核的低能正宇称态的能谱和电磁跃迁。应用U(5)→SU(3)的简化哈密顿量较好地描述了它们的能谱和电磁跃迁。研究结果表明，该核基本属于U(5)→SU(3)的过渡核Spectra and E2 transition rates for the even even 142-164Dy isotopes are studied in the framework of the interacting boson model. A schematic Hamiltonian capable of describing their spectra and transition is used. It is found that the even even 142-164Dy isotopes are in the transition from U(5)to SU(3) dynamical symmetry.     

Enhancement of B(E2) Collectivity in the sdg-Interacting Boson Model

It is pointed out that the difficulty in boson models in explaining the large B(E2) experimental data is not due to the lack of collectivity in boson model wavefunction. This long standing problem of reduction in collectivity of wavefunction in boson models can be solved by choosing an appropriate E2 transition operator in the SU(3) limit of the sdg-interacting boson model. The ratio B(E2, L + 2 → L)/B(E2,2 → 0) can be almost any large number.     

Littlest Higgs Model and Higgs Boson Associated Production with Top Quark Pair at High Energy Linear e+e- Collider

In the parameter space allowed by the electroweak precision measurement data, we consider the contributions of the new particles predicted by the littlest Higgs model to the Higgs boson associated production with top quark pair in the future high energy linear e⁺e^- collider (ILC). We find that the contributions mainly come from the new gauge bosons Z_H and B_H. For reasonable values of the free parameters, the absolute value of the relative correction parameter δσ/σ^SM can be significanly large, which might be observed in the future ILC experiment with √{S}=800 GeV.