标题： 弗洛凯绝缘体和超越简单时间离散化的格点费米子 显示英文标题

标题： Floquet insulators and lattice fermions beyond naive time discretization

摘要： 周期驱动的量子系统，称为Floquet绝缘体，可以容纳拓扑保护的束缚态，称为“$\pi$模式”，这些模式在驱动频率的一半处表现出响应。 这种状态也可以出现在未被驱动的格点场论中，当时间由于费米子加倍而被离散化时，这引发了这两个现象之间是否存在联系的问题。 最近，我们通过连续时间Floquet模型和离散时间未被驱动的格点费米子模型之间的显式映射，证明了这种联系。 然而，这种映射依赖于单粒子谱的一个对称性，该对称性在一般的驱动参数下并不存在。 受格点场论中时间威尔逊项的例子启发，本文通过允许离散时间模型的参数为频率相关的，将这种映射扩展到完整的驱动参数空间。 所得格点费米子模型的谱与Floquet模型在热力学极限下的准能量谱完全匹配。 我们的结果表明，Floquet系统中超越平衡物理的光谱特征可以通过适当的离散化时间的静态系统来复制。 显示英文摘要

摘要： Periodically driven quantum systems known as Floquet insulators can host topologically protected bound states known as "$\pi$ modes" that exhibit response at half the frequency of the drive. Such states can also appear in undriven lattice field theories when time is discretized as a result of fermion doubling, raising the question of whether these two phenomena could be connected. Recently, we demonstrated such a connection at the level of an explicit mapping between the spectra of a continuous-time Floquet model and a discrete-time undriven lattice fermion model. However, this mapping relied on a symmetry of the single-particle spectrum that is not present for generic drive parameters. Inspired by the example of the temporal Wilson term in lattice field theory, in this paper we extend this mapping to the full drive parameter space by allowing the parameters of the discrete-time model to be frequency-dependent. The spectra of the resulting lattice fermion models exactly match the quasienergy spectrum of the Floquet model in the thermodynamic limit. Our results demonstrate that spectral features characteristic of beyond-equilibrium physics in Floquet systems can be replicated in static systems with appropriate time discretization.