No exceptional precision of exceptional-point sensors
No exceptional precision of exceptional-point sensors
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DOI：
10.1103/physreva.98.023805
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发表时间：
2018-08-03
影响因子：
2.9
通讯作者：
Langbein, W.
中科院分区：
文献类型：
--
作者：
Langbein, W.
最近，在例外点（EP）的谐振传感器已被建议有一个大大提高的灵敏度，由于非凡的缩放的复杂的频率分裂的n个初始简并模式与第n根的扰动。我们在这里表明，所得到的量子限制的信号噪声在EP是成比例的扰动，并与其他传感器，从而提供相同的精度。因此，接近EP的复频率分裂不适合于估计EP传感器的精度。这个违反直觉的结果的根本原因是，模式场，所描述的本征向量，是平等的所有模式在EP，并强烈改变与微扰。
Recently, sensors with resonances at exceptional points (EPs) have been suggested to have a vastly improved sensitivity due to the extraordinary scaling of the complex frequency splitting of the n initially degenerate modes with the nth root of the perturbation. We show here that the resulting quantum-limited signal to noise at EPs is proportional to the perturbation, and comparable to other sensors, thus providing the same precision. The complex frequency splitting close to EPs is therefore not suited to estimate the precision of EP sensors. The underlying reason for this counterintuitive result is that the mode fields, described by the eigenvectors, are equal for all modes at the EP, and are strongly changing with the perturbation.