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arXiv 0807.3467nucl-thnucl-exquant-ph
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相互作用玻色子模型中的量子相变

Quantum phase transitions in the interacting boson model

Pavel Cejnar, Jan Jolie

摘要:

本文综述了原子核结构的相互作用玻色子模型(IBM)中量子相变的各种性质。该模型在其无限大小的限制表现出形状相变之间的球形,变形扁长,变形扁的形式的基态。这种行为的中子大小的前体被核性质(核质量、激发能、低位能级的跃迁几率)在整个核素图上的稳健变化所验证。同时,该模型作为一个理论实验室,用于研究QPT在相互作用的多体系统中的各种一般特征,这些特征在许多方面不同于固态物理的晶格模型。我们概述了目前感兴趣的最重要的领域:(a)第一和第二阶相变的共存支持QPT现象的微观起源相关的研究。(b)竞争的量子相位的特征在于特定的动力学对称性和新的对称性相关的方法来描述也过渡动力学域。(c)在某些参数区域,类似QPT的行为也可以归因于单个的激发态,这与系统的热力学和经典描述有关。(d)该模型及其相结构可以在许多方向上扩展:通过分离质子和中子激发,考虑奇费米子自由度或不同的粒子-空穴配置,通过包括其他类型的玻色子,高阶相互作用,并通过施加外部旋转。IBM相变的所有这些方面都与实验数据的解释有关,并且对于QPT现象的基本理解很重要。

英文摘要:

This review is focused on various properties of quantum phase transitions (QPTs) in the Interacting Boson Model (IBM) of nuclear structure. The model in its infinite-size limit exhibits shape-phase transitions between spherical, deformed prolate, and deformed oblate forms of the ground state. Finite-size precursors of such behavior are verified by robust variations of nuclear properties (nuclear masses, excitation energies, transition probabilities for low lying levels) across the chart of nuclides. Simultaneously, the model serves as a theoretical laboratory for studying diverse general features of QPTs in interacting many-body systems, which differ in many respects from lattice models of solid-state physics. We outline the most important fields of the present interest: (a) The coexistence of first- and second-order phase transitions supports studies related to the microscopic origin of the QPT phenomena. (b) The competing quantum phases are characterized by specific dynamical symmetries and novel symmetry related approaches are developed to describe also the transitional dynamical domains. (c) In some parameter regions, the QPT-like behavior can be ascribed also to individual excited states, which is linked to the thermodynamic and classical descriptions of the system. (d) The model and its phase structure can be extended in many directions: by separating proton and neutron excitations, considering odd-fermion degrees of freedom or different particle-hole configurations, by including other types of bosons, higher order interactions, and by imposing external rotation. All these aspects of IBM phase transitions are relevant in the interpretation of experimental data and important for a fundamental understanding of the QPT phenomenon.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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