Related Experiment Video
Updated: May 16, 2026

Measurement of Quantum Interference in a Silicon Ring Resonator Photon Source
Published on: April 4, 2017
Quantum metrological limits via a variational approach
B M Escher1, L Davidovich, N Zagury
1Instituto de Física, Universidade Federal do Rio de Janeiro, 21.941-972 Rio de Janeiro, Brazil. bmescher@if.ufrj.br
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.
Related Concept Videos
Calculation of First-Law Quantities II
The Uncertainty Principle
Calculation of First Law Quantities I
Uncertainty in Measurement: Reading Instruments
Estimation of the Physical Quantities
Limits of the First Law of Thermodynamics
