Quantum metrology is the use of genuinely quantum properties such as entanglement as a resource to outperform classical sensing strategies. Typically, entanglement is created by implementing gate operations or inducing many-body interactions. However, existing sensing schemes with these approaches require accurate control of the probe system such as switching on and off the interaction among qubits, which can be challenging for practical applications. Here, we propose an entanglement-enhanced sensing scheme with an always-on nearest-neighbor interaction between qubits. We adopt the transverse field Ising chain as the probe system, making use of the so-called quantum domino dynamics for the generation of the entangled states. In addition to the advantage that our scheme can be implemented without controlling the interactions, it only requires initialization of the system, projective measurements on a single qubit, and control of the uniform magnetic fields. We can achieve an improved sensitivity beyond the standard quantum limit even under the effect of realistic decoherence.

中文翻译：

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使用具有永远在线的最近邻相互作用的量子位链进行纠缠增强传感

量子计量是使用真正的量子特性（例如纠缠）作为一种优于经典传感策略的资源。通常，纠缠是通过实现门操作或诱导多体交互来创建的。然而，使用这些方法的现有传感方案需要对探针系统进行精确控制，例如打开和关闭量子位之间的交互，这对于实际应用来说可能具有挑战性。在这里，我们提出了一种纠缠增强传感方案，在量子位之间始终保持最近邻相互作用。我们采用横向场伊辛链作为探测系统，利用所谓的量子多米诺动力学来产生纠缠态。除了我们的方案可以在不控制交互的情况下实施的优势之外，它只需要系统的初始化、对单个量子位的投影测量以及均匀磁场的控制。即使在现实退相干的影响下，我们也可以实现超出标准量子极限的灵敏度。