Atomic Multipoles

W. E. Baylis

В. Е. Дмитриенко, Α. Kirfel, Elena N. Ovchinnikova

В. П. Демкин

Dieter Suter, Thomas Marty

The resonant interaction of optical radiation with atomic vapors can excite the atoms into anisotropic states with long lifetimes. The conventional description of these states uses an expansion in a basis of multipole moments, which are represented by irreducible tensor operators. We demonstrate an experimental method that permits the excitation of these atomic multipole moments in specific, experimentally controllable spatial orientations. Complementary optical methods permit the observation of multipole moments of arbitrary order and a direct measurement of their spatial orientation. We demonstrate these procedures in the ground state of atomic sodium, using optical pumping to polarize the angular-momentum substates. We show how the experimental results can be used to separate signal contributions that originate from different multipole moments.

Dieter Suter, Thomas Marty, Harald Klepel

The spatial orientation of atomic multipole moments can be observed optically with resonant polarized light. We demonstrate the procedure in the ground state of atomic sodium, using optical pumping to polarize the angular momentum substates. We show how the resulting information can be used to distinguish among signal contributions originating from different multipole moments.

A.S. Shumovsky

The author reviews investigations of the photon localization and quantum phase problems based on the use of the representation of multipole photons. Section II presents a general consideration of the field quantization, including a comparison of zero-point oscillations of the plane and multipole waves of photons. Section III discusses the atom-field interaction leading to the multipole radiation. The SU(2) quantum phase representation of atomic variables is considered, as is a connection between the SU(2) quantum phase states and entanglement phenomenon. In Section IV the author describes the quantum phase of multipole radiation caused by the angular momentum conservation in the process of radiation. This approach is compared with the Pegg–Barnett formalism and with Mandel's operational approach. Section V covers the quantum polarization properties of multipole radiation. Photon localization, quantum measurements, and causality are considered in Section VI.