Spin squeezing and precision probing with light and samples of atoms in the Gaussian description

Journal Article · Mon Nov 01 04:00:00 EST 2004 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.70.052324· OSTI ID:20646200

Madsen, Lars Bojer ^[1]; Moelmer, Klaus ^[2]

---

1. Department of Physics and Astronomy, University of Aarhus, 8000 Aarhus C (Denmark)
2. Danish National Research Foundation Center for Quantum Optics and Department of Physics and Astronomy, University of Aarhus, 8000 Aarhus C (Denmark)

We consider an ensemble of trapped atoms interacting with a continuous-wave laser field. For sufficiently polarized atoms and for a polarized light field, we may approximate the nonclassical components of the collective spin angular momentum operator for the atoms and the Stokes vectors of the field by effective position and momentum variables for which we assume a Gaussian state. Within this approximation, we present a theory for the squeezing of the atomic spin by polarization rotation measurements on the probe light. We derive analytical expressions for the squeezing with and without inclusion of the noise effects introduced by atomic decay and by photon absorption. The theory is readily adapted to the case of inhomogeneous light-atom coupling [A. Kuzmich and T.A.B. Kennedy, Phys. Rev. Lett. 92, 030407 (2004)]. As a special case, we show how to formulate the theory for an optically thick sample by slicing the gas into pieces, each having only small photon absorption probability. Our analysis of a realistic probing and measurement scheme shows that it is the maximally squeezed component of the atomic gas that determines the accuracy of the measurement.

• OSTI ID: 20646200
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 5 Vol. 70; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION
ACCURACY
ANGULAR MOMENTUM OPERATORS
ATOMS
COUPLING
DECAY
INFORMATION THEORY
LASER RADIATION
NOISE
PHOTON-ATOM COLLISIONS
PHOTONS
POLARIZATION
PROBABILITY
RADIATION PRESSURE
ROTATION
SPIN
TRAPPING
VECTORS
VISIBLE RADIATION