论文标题

Stark量子旋转链中的动力学量子相变

Dynamical quantum phase transitions in Stark quantum spin chains

论文作者

Faridfar, Mona, Fouladi, Ahmad A., Vahedi, Javad

论文摘要

我们研究了在存在均匀力的情况下,一维自旋模型的非平衡动力学。线性电势在自由粒子模型中诱导定位 - 定位转变,该模型被称为Wannier-Stark效应。我们研究了由于系统经历定位 - 移位转变时,由于跨量子临界点的突然全局淬火而研究动力学量子相变(DQPT)。在这方面,我们考虑XX和XXZ旋转链,并探索两种类型的淬火,而没有通过到达定位位定位点逐渐升起。将XX模型映射到游离费米亚颗粒,因此提供了分析结果和数值结果。结果揭示了定位 - 偏置转变的动态特征的特征是动态自由能中的非分析性(对应于Loschmit Echo中的零点)。我们还使用数值DMRG技术的时间依赖性扩展考虑了考虑XXZ旋转链的相互作用效应。我们的结果表明,根据各向异性参数$δ\ LessGtr1.0 $,如果初始和季度后的哈密顿量是否处于同一阶段,则可能发生DQPT。此外,具有不同相关度量的DQPT之间的相互关系,例如平衡阶参数或系统的纠缠熵产生。通过将它们连接到平均局部磁化,纠缠熵产生和Schmidt GAP,我们将对DQPT的特征进行更多分析。

We investigate the nonequilibrium dynamics of one-dimension spin models in the presence of a uniform force. The linear potential induces delocalization-localization transition in the free particles model which is known as the Wannier-Stark effect. We study dynamical quantum phase transition (DQPT) due to sudden global quenches across a quantum critical point when the system undergoes a localization-delocalization transition. In this regard, we consider the XX and XXZ spin chains and explore two types of quenches with and without ramping through the delocalization-localization point. The XX model was mapped to the free fermion particles, so both analytical and numerical results were provided. Results unveil that the dynamical signature of localization-delocalization transition can be characterized by the nonanalyticities in dynamical free energy (corresponds to the zero points in the Loschmit echo). We also explore the interaction effects considering XXZ spin chains, using the time-dependent extension of the numerical DMRG technique. Our results show that depending on the anisotropic parameter $Δ\lessgtr1.0$, if both the initial and post-quench Hamiltonian are in the same phase or not, DQPTs may happen. Moreover, the interrelation between DQPTs with different correlation measures such as the equilibrium order parameters or entanglement entropy production of the system remains unclear. We provide more analyses on the feature of DQPTs, in both types of quenches, by connecting them to the average local magnetization, entanglement entropy production, and the Schmidt gap.

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