奇奇核形状相变代数模型分析

Algebraic model analysis of shape phase transitions in odd-odd nuclei

与偶偶核系统相比,同时包含单粒子激发和集体激发的奇奇核系统的低激发态动力学结构及其演化相对来说更难被描述.相互作用玻色子费米子费米子模型(简称IBFFM)提供了一个描述奇奇核结构性质的代数模型框架.针对模型求解,本文提出在SU(3)基底下构建哈密顿量矩阵的数值算法,并据此应用IBFFM模型分析两种不同单粒子组态下的奇奇核系统形状相变.结果表明,奇粒子效应将进一步强化不同特征量在U(5)-SU(3)与U(5)-O(6)相变过程中演化的临界行为,进而肯定形状相变也将是中重质量区奇奇核结构演化的重要方式.

Compared with even-even nuclei,the description of low-lying dynamical structures and their evolution in odd-odd nuclei,which involve single-particle and collective excitations,is relatively difficult.Notably,the interacting bosonfermion-fermion model(IBFFM)provides an algebraic model framework to describe the structural properties of odd-odd nuclei.To solve the model,a numerical algorithm for constructing the Hamiltonian matrix in terms of the SU(3)basis is introduced in this work,through which the IBFFM is applied to analyze shape phase transitions in odd-odd nucleus systems with two different single-particle configurations.The results indicate that the critical behaviors of different quantities in the U(5)-SU(3)and U(5)-O(6)phase transitions will be further strengthened by the odd-particle effects,which confirms that shape phase transitions are important ways of structural evolution in odd-odd nuclei in heavy or intermediately heavy mass regions.