标题： 形状共生与量子相变之间的微妙联系。 锆的案例 显示英文标题

标题： The subtle connection between shape coexistence and quantum phase transition. The Zr case

摘要： 背景：锆区域的特点是核基态结构发生非常快速的变化。 特别是从$^{98}$锆过渡到$^{100}$锆时变形的开始，在核图中是迄今为止观察到最快的之一。 实验和理论研究都证明了某些低激发态的锆同位素拥有与基态不同的形状。 目的：我们旨在解开基态形状突然变化之间的相互作用，即量子相变的存在，以及具有非常不同变形的共存状态在光谱中的存在，即形状共存的存在。 方法：我们依赖于先前使用带有构型混合的相互作用玻色子模型（IBM-CM）的计算，该计算详细再现了$^{96-110}$锆的光谱性质。 这种 IBM-CM 计算允许计算平均场能量曲面、波函数以及与形状共存或量子相变相关的任何其他可观测量。 结果：我们获得了能量曲面和变形参数$\beta$的平衡值，波函数的 U(5) 分解以及态密度。 结论：我们确认锆是源自两种具有非常不同变形程度的构型交叉的一个明显的量子相变的例子。 此外，我们观察到入侵构型自身表现出的演化也类似于一个量子相变。 显示英文摘要

摘要： Background: Zr region is characterized by very rapid changes in the ground state structure of the nuclei. In particular, the onset of deformation when passing from $^{98}$Zr to $^{100}$Zr is one of the fastest ever observed in the nuclear chart. It has been probed both experimental and theoretically that certain low-lying excited states of Zr isotopes own different shapes than the ground state. Purpose: We intend to disentangle the interplay between the sudden changes in the ground state shape, i.e., the existence of a quantum phase transition, and the presence in the spectra of coexisting states with very different deformation, i.e., the presence of shape coexistence. Method: We rely on a previous calculation using the Interacting Boson Model with Configuration Mixing (IBM-CM) which reproduces in detail the spectroscopic properties of $^{96-110}$Zr. This IBM-CM calculation allows to compute mean-field energy surfaces, wave functions and any other observable related with the presence of shape coexistence or with a quantum phase transition. Results: We obtain energy surfaces and the equilibrium value of the deformation parameter $\beta$, the U(5) decomposition of the wave functions and the density of states. Conclusions: We confirm that Zr is a clear example of quantum phase transition that originates from the crossing of two configurations with a very different degree of deformation. Moreover, we observe how the intruder configuration exhibits its own evolution which resembles a quantum phase transition too.