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Contents I. Methods 1 A. Atom preparation 1 B. Correlation measurements 2 II. A two-component effective equation governing polariton dynamics 2 A. Single-particle dynamics 3 B. Two-particle dynamics 4 C. Comparing full theory with two-component effective theory 7

In this paper, we present a theoretical model for studying the interaction between linearly polarized laser light and near-degenerated Zeeman sublevels for a multiple V-type atomic system of 2 S 1/2 F g =2→ 2 P 3/2 F e = 3 transition in 87 Rb. We have calculated the laser absorption in a Hanle configuration, as well as the amplitudes and the widths of electromagnetically induced absorption ͑EIA͒ in the range of laser intensities from 0.01 to 40 mW/ cm 2 . Our results, showing nonvanishing EIA amplitude, a nonmonotonic increase of the EIA width for the increase of laser intensity, and pronounced shape differences of the Hanle EIA curves at different laser intensities, are in good agreement with recent experimental results. We have found that the EIA behaves differently than the electromagnetically induced transparency ͑EIT͒ as a function of the laser intensity. Both the amplitude and width of the EIA have narrow maximums at 1 to 2 mW/ cm 2 . We have shown the strong influence of Doppler broadening of atomic transition on Hanle resonances and have suggested the explanation of it.

The influence of crossed electric and magnetic fields on dielectronic recombination of Ne 7ϩ ions has been measured at the Stockholm heavy-ion storage ring CRYRING. The electron energy range covered all dielectronic recombination resonances attached to 2s→2p 1/2 and 2s→2p 3/2 ⌬nϭ0 core excitations. Two sets of measurements at magnetic fields of 180 mT and 30 mT have been performed. For the measurement at 180 mT we applied 25 different electric fields between 0 and 1400 V/cm. The resonance strength for dielectronic recombination via high Rydberg states initially increases linearly with electric field and later levels out. At a magnetic field of 30 mT we applied 15 different electric fields ranging from 0 to 140 V/cm. Compared to the measurement at 180 mT the initial slope of the rate enhancement was larger by almost a factor of 2. The fraction of resonant strength not measured due to field ionization is estimated by a model calculation of dielectronic recombination cross sections.

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