General framework for estimating the ultimate precision limit in Bayesian quantum metrology
Phys. Rev. A 113, 022212 – Published 17 February, 2026
DOI: https://doi.org/10.1103/j245-wrkp
Abstract
Quantum Fisher information (QFI) quantifies the precision that nonrandom parameters can be estimated using quantum probes and unbiased estimators. We demonstrate that QFI, associated with a quantum displacement estimation, precisely sets the minimal estimation uncertainty in quantum random parameter estimation. We establish a general framework for bounding the minimal estimation uncertainty in Bayesian quantum metrology, providing tight lower limits, which systematically enable quantum generalizations of classical precision bounds. Our framework enables the tightening of existing quantum bounds, the development of bounds that exploit the physical properties of noisy systems in realistic and specific scenarios, and the derivation of exact results within a unified quantum nonrandom estimation approach.
