Adaptive Non-Orthogonal Quantum Measurement Technology Based on Real-Time Optimization of Fisher Information

SF6, widely used as an insulating medium in substation equipment, has discharge decomposition products (such as SOF2, H2S, CO, etc.), and the concentration changes of these products are important indicators for assessing the insulation degradation of the equipment. Traditional nonorthogonal quantum measurement techniques are limited by fixed post-selected states and weak coupling conditions, making it difficult to meet the gas concentration detection requirements in complex power grid environments with large dynamic ranges and strong background noise. This work proposes an adaptive measurement framework that dynamically optimizes Fisher information in real time through closed-loop adjustments of postselection states. Theoretical analysis reveals that maximizing Fisher information at the quantum limit is achievable when the quantum amplification factor becomes purely imaginary, enabling significant relaxation of weak-coupling conditions. Numerical simulations confirm that the adaptive protocol maintains optimal sensitivity across extended parameter ranges, whereas conventional methods exhibit Lorentz-type decay in Fisher information as parameters deviate from their narrow optimal zone. By integrating dynamic state adaptation and feedback control, this approach establishes a generalized paradigm for designing quantum sensing systems with enhanced robustness and scalability.