In quantum mechanics, the observer necessarily plays an active role in the dynamics of the system, making it difficult to probe a system without disturbing it. Here, we leverage this apparent difficulty as a tool for driving an initially trivial system into a chiral phase. In particular, we show that by utilizing a pattern of repeated occupation measurements we can produce chiral edge transport of fermions hopping on a Lieb lattice. The procedure is similar in spirit to the use of periodic driving to induce chiral edge transport in Floquet topological insulators, while also exhibiting novel phenomena due to the nonunitary nature of the quantum measurements. We study in detail the dependence of the procedure on measurement frequency, showing that in the Zeno limit the system can be described by a classical stochastic dynamics, yielding protected transport. As the frequency of measurements is reduced, the charge flow is reduced and vanishes when no measurements are done.

中文翻译：

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凝视搅拌：测量诱导的手性

在量子力学中，观察者必然在系统动力学中发挥积极作用，因此很难在不干扰系统的情况下对其进行探测。在这里，我们利用这一明显的困难作为将最初微不足道的系统驱动到手性相的工具。特别是，我们表明，通过利用重复占据测量的模式，我们可以产生在 Lieb 晶格上跳跃的费米子的手性边缘传输。该过程在本质上类似于使用周期性驱动来诱导 Floquet 拓扑绝缘体中的手性边缘传输，同时由于量子测量的非统一性而表现出新的现象。我们详细研究了程序对测量频率的依赖性，表明在芝诺极限中，系统可以用经典的随机动力学来描述，产生受保护的运输。随着测量频率的降低，电荷流减少并且在没有进行测量时消失。