1212.2533 (B. M. Escher)

Quantum Noise-to-Sensibility Ratio    [PDF]

B. M. Escher

The quantum variables that can be accessed directly by experiments are described by observables. Therefore, physical parameters can only be evaluated indirectly, via estimations based on experimental measurement results. I show that the quantum sensitivity, or the quantum statistical uncertainty in single-parameter estimation, can be defined as the (minimal) ratio between noise and sensibility with a parameter of a well-calibrated observable. Among one of its applications, I show that, measuring a convenient quadrature in squeezed probe oscillators, it is possible to surpass the standard precision limit in phase-shift estimations, even in presence of moderate phase diffusion.

View original: http://arxiv.org/abs/1212.2533