论文标题
拓扑时空晶体
Topological space-time crystal
论文作者
论文摘要
我们引入了一类新的平衡非相互作用拓扑阶段，即拓扑时空晶体。这些是时间依赖性的量子系统，没有离散的空间翻译对称性，而是在离散的时空翻译下是不变的。与Floquet-Bloch系统类似，可以通过频率域增强的哈密顿量来描述时空晶体，该晶体用来对拓扑上不同的时空晶体进行分类。我们表明，这些时空晶体可以从传统的晶体进行设计，并具有额外的时间依赖性驱动器，其行为就像在晶体上移动的行动波一样。有趣的是，我们能够基于仅涉及一个轨道的紧密结合模型来构建拓扑空间晶体的1D和2D示例，与任何先前发现的静态静态或浮雕拓扑阶段具有晶体结构的两轨最小模型相比。
We introduce a new class of out-of-equilibrium noninteracting topological phases, the topological space-time crystals. These are time-dependent quantum systems which do not have discrete spatial translation symmetries, but instead are invariant under discrete space-time translations. Similar to the Floquet-Bloch systems, the space-time crystals can be described by a frequency-domain-enlarged Hamiltonian, which is used to classify topologically distinct space-time crystals. We show that these space-time crystals can be engineered from conventional crystals with an additional time-dependent drive that behaves like a traveling wave moving across the crystal. Interestingly, we are able to construct 1D and 2D examples of topological space-time crystals based on tight-binding models which involve only one orbital, in contrast to the two-orbital minimal models for any previous discovered static or Floquet topological phases with crystalline structures.
