We consider the Su-Schrieffer-Heeger (SSH) chain, which has 0, 1, or 2 topological edge states depending on the ratio of the hopping parameters and the parity of the chain length. We couple a qubit to one edge of the SSH chain and a semi-infinite undimerized chain to the other, and evaluate the dynamics of the qubit. By evaluating the decoherence rate of the qubit we can probe the edge states of the SSH chain. The rate shows strong even-odd oscillations with the number of sites reflecting the presence or absence of edge states. Hence, the qubit acts as an efficient detector of the topological edge states of the SSH model. This can be generalized to other topological systems.

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用量子比特的动力学检测拓扑边缘状态

我们考虑 Su-Schrieffer-Heeger (SSH) 链，它具有 0、1 或 2 个拓扑边缘状态，具体取决于跳跃参数的比率和链长的奇偶校验。我们将一个量子位耦合到 SSH 链的一个边缘，将一个半无限未二聚化链耦合到另一个边缘，并评估量子位的动力学。通过评估量子比特的退相干率，我们可以探测 SSH 链的边缘状态。该速率显示出强烈的奇偶振荡，站点数量反映了边缘状态的存在与否。因此，量子位充当 SSH 模型拓扑边缘状态的有效检测器。这可以推广到其他拓扑系统。