论文标题
激发态量子相变的Anharmonic Lipkin-Meshkov-Glick-Glick模型I：静态方面
Excited-State Quantum Phase Transitions in the Anharmonic Lipkin-Meshkov-Glick Model I: Static Aspects
论文作者
论文摘要
基本的Lipkin-Meshkov-Glick模型显示二阶基态量子相变和激发态量子相变（ESQPT）。在哈密顿量中包含一个非谐的术语意味着第二个具有不同性质的esqpt。我们使用模型的平均场限制来表征此ESQPT。可以使用基态量子相变的顺序参数，相邻状态之间的能量差距，参与率和量子保真度敏感性，与系统的有限希尔伯特空间边界的变化相关的新ESQPT。
The basic Lipkin-Meshkov-Glick model displays a second order ground state quantum phase transition and an excited state quantum phase transition (ESQPT). The inclusion of an anharmonic term in the Hamiltonian implies a second ESQPT of a different nature. We characterize this ESQPT using the mean field limit of the model. The new ESQPT, associated with the changes in the boundary of the finite Hilbert space of the system, can be properly described using the order parameter of the ground state quantum phase transition, the energy gap between adjacent states, the participation ratio, and the quantum fidelity susceptibility.
