Orientationtoalignment conversion and spin squeezing
Abstract
The relationship between orientationtoalignment conversion (a form of atomic polarization evolution induced by an electric field) and the phenomenon of spin squeezing is demonstrated. A “stretched” state of an atom or molecule with maximum angularmomentum projection along the quantization axis possesses orientation and is a quantummechanical minimumuncertainty state, where the product of the equal uncertainties of the angularmomentum projections on two orthogonal directions transverse to the quantization axis is the minimum allowed by the uncertainty relation. Application of an electric field for a short time induces orientationtoalignment conversion and produces a spinsqueezed state, in which the quantum state essentially remains a minimumuncertainty state, but the uncertainties of the angularmomentum projections on the orthogonal directions are unequal. This property can be visualized using the angularmomentum probability surfaces, where the radius of the surface is given by the probability of measuring the maximum angularmomentum projection in that direction. Brief remarks are also given concerning collectivespin squeezing and quantum nondemolition measurements.
 Publication:

Physical Review A
 Pub Date:
 February 2012
 DOI:
 10.1103/PhysRevA.85.022125
 arXiv:
 arXiv:1106.3538
 Bibcode:
 2012PhRvA..85b2125R
 Keywords:

 03.65.Ta;
 42.50.Dv;
 32.60.+i;
 Foundations of quantum mechanics;
 measurement theory;
 Nonclassical states of the electromagnetic field including entangled photon states;
 quantum state engineering and measurements;
 Zeeman and Stark effects;
 Physics  Atomic Physics;
 Quantum Physics
 EPrint:
 7 pages, 6 figures