Quantum Metrological Limits via a Variational Approach
Quantum Physics
2012-11-21 v2
Abstract
The minimum achievable statistical uncertainty in the estimation of physical parameters is determined by the quantum Fisher information. Its computation for noisy systems is still a challenging problem. Using a variational approach, we present an equation for obtaining the quantum Fisher information, which has an explicit dependence on the mathematical description of the noise. This method is applied to obtain a useful analytical bound to the quantum precision in the estimation of phase-shifts under phase diffusion, which shows that the estimation uncertainty cannot be smaller than a noise-dependent constant.
Cite
@article{arxiv.1207.3307,
title = {Quantum Metrological Limits via a Variational Approach},
author = {B. M. Escher and L. Davidovich and N. Zagury and R. L. de Matos Filho},
journal= {arXiv preprint arXiv:1207.3307},
year = {2012}
}
Comments
Published Version: 5 pages (including references), 1 figure, typos corrected, and text little bit improved