Journal of the Optical Society of America B

Effects of phase fluctuations on weak-value-based quantum metrology

Qing-Lin Wu, Ke-Xuan Chen, Zi-Rui Zhong

Published Aug 1, 2025• 0 citations

Abstract

Weak measurement has ignited extensive research and discussions in the field of quantum metrology due to its sufficient potential in quantum measurement applications. Recent studies demonstrate that weak measurement protocols, when integrated with quantum resources, can achieve Heisenberg scaling while maintaining technical noise advantages. However, scenarios involving dephasing noise have not been addressed, as such noise induces rapid degradation of Heisenberg scaling to the standard quantum limit. Here, we incorporate phase fluctuations, a typical dephasing noise, into three Heisenberg-scaling systems. We find that postselection invariably reduces the robustness of quantum systems. Compared to coherent pointer states, squeezed coherent pointer states can exhibit superior resilience against phase fluctuations through appropriate squeezing-parameter optimization. In addition, in entanglement-assisted systems, we can optimize the postselected angle to compensate for Fisher information loss induced by the postselection process. Our findings reveal that weak measurement exhibits inherent limitations in dephasing noise metrology compared to conventional measurement.

DOI: 10.1364/josab.569415

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