15 research outputs found
Temperature and polarization angular power spectra of Galactic dust radiation at 353 GHz as measured by Archeops
We present the first measurement of temperature and polarization angular
power spectra of the diffuse emission of Galactic dust at 353 GHz as seen by
Archeops on 20% of the sky. The temperature angular power spectrum is
compatible with that provided by the extrapolation to 353 GHz of IRAS and DIRBE
maps using \cite{fds} model number 8. For Galactic latitudes deg
we report a 4 sigma detection of large scale ()
temperature-polarization cross-correlation and set upper limits to the and modes at . For Galactic latitudes deg, on the same
angular scales, we report a 2 sigma detection of temperature-polarization
cross-correlation . These
results are then extrapolated to 100 GHz to estimate the contamination in CMB
measurements by polarized diffuse Galactic dust emission. The signal is
then and for and 10 deg.
respectively. The upper limit on and becomes . If polarized dust emission at higher Galactic latitude cuts is
similar to the one we report here, then dust polarized radiation will be a
major foreground for determining the polarization power spectra of the CMB at
high frequencies above 100 GHz.Comment: 11 pages, 8 figures, submitted to A
Determination of the calcium ground state scattering length by photoassociation spectroscopy at large detunings
Photoassociation spectroscopy was used to determine the s-wave scattering length of 40Ca atoms in their electronic ground state. Vibrational levels were observed in an extended range of up to 182 GHz below the dissociation limit 4s21S0–4s4p 1P1. Thus, the frequency interval was nearly tripled, in which photoassociation was observed compared to previous measurements. The spectra were analyzed by means of quantum mechanical simulations. With the new data it was possible to resolve the discrepancy concerning the ground state scattering length presented in earlier publications [Phys. Rev. A 67, 043408 (2003); Eur. Phys. J. D 26, 155 (2003)]. An improved dipole-dipole coupling constant C3Σ = 0.52306(20) ×103 cm-1 nm3 is obtained
Franges de Ramsey à deux photons à 10,6gm amélioration de la résolution et perspectives métrologiques
Nous avons pu enregistrer des signaux de franges de Ramsey à 10.6 m sur un jet supersonique de SF, avec une période de 400 HZ et un rapport signal sur bruit de 20 dans une bande passant de 1 Hz. Les performances métrologiques atteintes par cette nouvelle source sont désormais comparables à celle de l'étalon actuel a 10.6
Feasibility of narrow-line cooling in optical dipole traps
We have investigated the influence of narrow-line laser cooling on the loading of Ca atoms into optical dipole traps.
To describe the narrow-line cooling of alkaline-earth atoms in combination with optical dipole trapping, we have developed a model
that takes into account the light shifts of the cooling transition in three dimensions.
The model is compared with two experimental realizations of optical dipole traps for calcium at the wavelengths 514 nm and
10.6 μm