Gaussian Description of Squeezed Light and Magnetometry

Vivi Petersen, Lars Bojer Madsen

Kosuke Shibata, Naota Sekiguchi, Aki Torii +2 more

Zhihao Xiao, R. Nicholas Lanning, M. Zhang +3 more

Klaus Mølmer, Lars Bojer Madsen

We present a theory for the estimation of a classical magnetic field by an atomic sample with a Gaussian distribution of collective spin components. By incorporating the magnetic field and the probing laser field as quantum variables with Gaussian distributions on equal footing with the atoms, we obtain a very versatile description which is readily adapted to include probing with squeezed light, dissipation, and loss and additional measurement capabilities on the atomic system.

Vivi Petersen, Lars Bojer Madsen, Klaus Mølmer

We present a Gaussian-state description of squeezed light generated in an optical parametric oscillator. Using the Gaussian-state description we describe the dynamics of the system conditioned on homodyne detection on the output field. Our theory shows that the output field is squeezed only if observed for long enough times or by a detector with finite bandwidth. As an application of the present approach we consider the use of finite bandwidth squeezed light together with a sample of spin-polarized atoms to estimate a magnetic field.

M. D. Reid, Alistair S. Lane, Daniel F. Walls