标题： 通过扩展的苏-施里弗-黑格模型从纯态到混态探索动力学量子相变 显示英文标题

标题： Exploring dynamical quantum phase transition from pure states to mixed states through extended Su-Schrieffer-Heeger models

摘要： 我们研究了扩展SSH模型框架中纯态和混合态中的动态量子相变（DQPTs），重点关注SSH-3和SSH-4变体，它们在对称性特性上有所不同。 SSH-3模型具有类似手征对称性的点对称性，而不是真正的手征对称性，它支持与拓扑性质相关的稳健局域边缘态。 我们的结果表明，对于纯态，在跨越拓扑转变的淬火后会发生DQPT，即使能带间隙保持开放。 对于混合态，DQPT行为在低温下与纯态一致，但在较高温度下会发生显著变化，包括多个临界时间的出现。 相比之下，SSH-4模型具有手征对称性，具有四种不同的能谱配置。 我们发现，纯态的DQPT仅在淬火从无能隙初始状态开始并跨越临界拓扑点时才会出现。 在有限温度下，混合态的DQPT只有在相应的纯态淬火引发DQPT时才在低温下持续存在，但在高温下会消失。 这些发现阐明了对称性、拓扑性和温度在控制广义SSH模型中DQPT方面的相互作用。 显示英文摘要

摘要： We investigate dynamical quantum phase transitions (DQPTs) in both pure and mixed states within the extended SSH model framework, focusing on the SSH-3 and SSH-4 variants, which differ in symmetry properties. The SSH-3 model, characterized by a chiral-like point symmetry rather than true chiral symmetry, supports robust localized edge states tied to its topological nature. Our results show that for pure states, DQPTs occur after quenches crossing the topological transition, even when the energy band gap remains open. For mixed states, DQPT behavior aligns with pure states at low temperatures but undergoes significant changes at higher temperatures, including the emergence of multiple critical times. In contrast, the SSH-4 model, which possesses chiral symmetry, features four distinct energy spectrum configurations. We find that pure-state DQPTs arise only when the quench starts from a gapless initial state and crosses the critical topological point. At finite temperature, mixed-state DQPTs persist at low temperatures only if the corresponding pure-state quench induces DQPTs, but they disappear at elevated temperatures. These findings elucidate the interplay between symmetry, topology, and temperature in governing DQPTs within generalized SSH models.