Quantum estimation of coupled parameters and the role of entanglement

Pieter Kok, Jacob Dunningham and Jason F. Ralph

Physical Review A 95, 012326 (2017)

pdf

The quantum Cramer-Rao bound places a limit on the mean square error of a parameter estimation procedure, and its numerical value is determined by the quantum Fisher information. For single parameters, this leads to the well- known Heisenberg limit that surpasses the classical shot-noise limit. When estimating multiple parameters, the situation is more complicated and the quantum Cramer-Rao bound is generally not attainable. In such cases, the use of entanglement typically still offers an enhancement in precision. Here, we demonstrate that entanglement is detrimental when estimating some nuisance parameters. In general, we find that the estimation of coupled parameters does not benefit from either classical or quantum correlations. We illustrate this effect in a practical application for optical gyroscopes.

main image

Publications
Research
Teaching

© 2017 Pieter Kok

Member of The Internet Defense League