论文标题
钻石晶格中平坦带的周期性和上的动力学
Periodic and aperiodic dynamics of flat bands in diamond-octagon lattice
论文作者
论文摘要
我们定期通过在两个汉密尔顿之间切换两个不同的磁通量穿过钻石斑块，以研究拓扑平面带的产生，从而定期驾驶二维钻石晶格模型。我们表明，以这种方式，可以对模型的所有频带的平坦性和拓扑性质进行调整，并且可以使floquet quasi-sates在拓扑上保持平整，而其静态对应物不支持拓扑和平坦度的存在。通过在非平衡动力学的背景下相应地重新定义平坦度，并使用状态的floquet关节密度正确地证明它是合理的，当与步骤hamiltonian和verms相关的时间窗口组成的输入参数空间变得更大时，就可以更好地控制所需结果，而不是仅由磁性通量组成的静态参数空间。有趣的是，我们发现了通量电流的产生。我们系统地分析了在渐近极限中完成的工作和磁通电流作为输入参数的函数，以表明拓扑和平坦度分别与通量电流和所做的工作有着密切的连接。我们最终将调查扩展到台阶哈密顿阶段的周期性阵列，如果初始状态基本上平坦，则可以大大减少加热问题，因为初始状态的较大状态可阻止该系统轻松从大道驾驶中吸收能量。我们还表明，如果台阶中的磁通量很小，这些通量的持续时间不相等，并且在频带的初始平坦度上，则可以减少加热。我们通过合理的分析论点成功解释了我们的发现。
We drive periodically a two-dimensional diamond-octagon lattice model by switching between two Hamiltonian corresponding two different magnetic flux piercing through diamond plaquette to investigate the generation of topological flat bands. We show that in this way, the flatness and topological nature of all the bands of the model can be tuned and Floquet quasi-sates can be made topologically flat while its static counterpart does not support the existence of topology and flatness together. By redefining the flatness accordingly in the context of non-equilibrium dynamics and correctly justifying it using the Floquet joint density of states, one indeed obtains a better control of the desired result when the input parameter space composed of temporal window associated with the step Hamiltonian and flux becomes larger than the static parameter space consisting of magnetic flux only. Interestingly, we find the generation of flux current. We systematically analyse the work done and flux current in the asymptotic limit as a function of input parameters to show that topology and flatness both share a close connection to the flux current and work done, respectively. We finally extend our investigation to the aperiodic array of step Hamiltonian, where we find that the heating up problem can be significantly reduced if the initial state is substantially flat as initial the large degeneracy of states prevents the system from absorbing energy easily from the aperiodic driving. We additionally show that the heating can be reduced if the values of the magnetic flux in the step Hamiltonian are small, the duration of these flux are unequal and on the initial flatness of the band. We successfully explain our finding by plausible analytical arguments.
