Ultimate precision of joint quadrature parameter estimation with a Gaussian probe

Abstract

The Holevo Cramér Rao bound is a lower bound on the sum of the mean square error of estimates for parameters of a state. We provide a method for calculating the Holevo Cramér-Rao bound for estimation of quadrature mean parameters of a Gaussian state by formulating the problem as a semidefinite program. In this case, the bound is tight; it is attained by purely Guassian measurements. We consider the example of a symmetric two-mode squeezed thermal state undergoing an unknown displacement on one mode. We calculate the Holevo Cramér-Rao bound for joint estimation of the conjugate parameters for this displacement. The optimal measurement is different depending on whether the state is entangled or separable.

12 pages, 2 figures

References in corpus (4)

• Operational Significance of Discord Consumption: Theory and Experiment
• Optimal estimation of joint parameters in phase space
• Bounds on Quantum Multiple-Parameter Estimation with Gaussian State
• Estimation of unitary quantum operations

Cited by in corpus (2)

• Single-shot non-Gaussian Measurements for Optical Phase Estimation
• Attainability of the Holevo-Cramér-Rao bound for two-qubit 3D magnetometry