Enhanced quantum parameter estimation via dynamical modulation
Phys. Rev. Applied 23, 064024 – Published 10 June, 2025
DOI: https://doi.org/10.1103/njh2-4jwf
Abstract
In quantum theory, the inescapable interaction between a system and its surroundings will lead to a loss of coherence and leakage of information into the environment. One approach to retain the quantum characteristics of the system is to dynamically mitigate or eliminate the impact of the environment on the system. However, things get complicated in quantum parameter estimation tasks, especially when the unknown parameter originates from the environment. Here we propose a general dynamical modulation scheme that enables increase of estimation precision irrespective of the origin of the parameters to be estimated. Notably, beyond the capability of dynamically decoupling the system from the environment, our proposal can select the effective frequency of the system and, in turn, manipulate the dynamics of the system, such as the steady-state probability and the decay rate, which are sensitive to the bath parameter. Therefore, the quantum Fisher information is dramatically increased, leading to superior estimation precision. Specifically, we elucidate the effectiveness of our proposal with prototypical examples of Ramsey spectroscopy and the quantum thermometer. Our findings offer an alternative route to increase the precision of quantum estimation processes and may have potential applications in diverse branches of quantum metrology.
