标题： 动态轴子场与一维无自旋费米子的耦合 显示英文标题

标题： Dynamical axion fields coupled with one-dimensional spinless fermions

摘要： 我们研究了一维晶格上无自旋费米子与链接上自旋的耦合动力学。 当费米子的跃迁积分和局域势依赖于链接自旋的方向时，低能有效理论预测链接自旋在1+1维中表现为动态轴子场。 轴子场$\theta$通过$\theta E$与电场$E$耦合，通过这种方式，链接自旋会响应施加的电场或电中性费米子的化学势梯度而旋转。 这是 Rice-Mele 模型中 Thouless 泵浦的逆现象。 通过将链接自旋近似为经典自旋并利用轴子拉格朗日量分析动力学后，我们使用张量网络方法展示了全量子动力学。 尽管在求解费米子-自旋耦合多体动力学时没有显式引入轴子拉格朗日量，但全量子结果与经典自旋近似的结果相符，包括轴子场的动力学和费米子输运。 此外，我们发现自旋之间的量子关联加速了轴子场的动力学，因为链接自旋期望值的抑制使它们更容易旋转。 我们还提出了一种可能的实验设置，用于冷原子系统实现本研究中的哈密顿量。 显示英文摘要

摘要： We investigate coupled dynamics of spinless fermions on a one-dimensional lattice and spins on the links. When the hopping integral and the on-site potential of the fermions depend on the direction of the link spins, the low-energy effective theory predicts that the link spins behave as a dynamical axion field in 1+1 dimensions. The axion field $\theta$ is coupled to the electric field $E$ as $\theta E$, through which the link spins rotate in response to the applied electric field or the chemical potential gradient for charge-neutral fermions. This is the inverse phenomenon of Thouless pumping in the Rice-Mele model. After analyzing the dynamics by approximating the link spins with the classical ones and utilizing the axion Lagrangian, we show the full-quantum dynamics using the tensor network method. Even though we do not explicitly introduce the axion Lagrangian in solving the fermion-spin coupled many-body dynamics, the full-quantum results agree well with those with the classical spin approximation, including the dynamics of the axion field and fermion transport. In addition, we find that the quantum correlation between spins accelerates the dynamics of axion fields as the suppression of the expectation values of the link spins allows them to rotate easily. We also propose a possible experimental setup for cold-atomic systems to implement the Hamiltonian in this study.