Peng Jia-Xin, Zhu Baiqiang, Zhang Weiping, Zhang Keye
Quantum Institute for Light and Atoms, State Key Laboratory of Precision Spectroscopy, Department of Physics, School of Physics and Electronic Science, <a href="https://ror.org/02n96ep67">East China Normal University</a>, Shanghai 200062, China.
School of Physics and Astronomy, and Tsung-Dao Lee Institute, <a href="https://ror.org/0220qvk04">Shanghai Jiao Tong University</a>, Shanghai 200240, China.
Phys Rev Lett. 2024 Aug 30;133(9):090801. doi: 10.1103/PhysRevLett.133.090801.
The detrimental impact of noise on sensing performance in quantum metrology has been widely recognized by researchers in the field. However, there are no explicit fundamental laws of physics stating that noise invariably weakens quantum metrology. We reveal that phase-covariant noise either degrades or remains neutral to sensing precision, whereas non-phase-covariant noise can potentially enhance parameter estimation, surpassing even the ultimate precision limit achievable in the absence of noise. This implies that a non-Hermitian quantum sensor may outperform its Hermitian counterpart in terms of sensing performance. To illustrate and validate our theory, we present several paradigmatic examples of magnetic field metrology.
噪声对量子计量学中传感性能的不利影响已得到该领域研究人员的广泛认可。然而，目前尚无明确的基础物理定律表明噪声总是会削弱量子计量学。我们发现，相位协变噪声要么会降低传感精度，要么对其保持中性，而非相位协变噪声则有可能提高参数估计，甚至超过无噪声情况下可达到的最终精度极限。这意味着非厄米量子传感器在传感性能方面可能优于其厄米对应物。为了说明和验证我们的理论，我们给出了几个磁场计量学的典型例子。
