Combining gravity with the forces of the standard model on a cosmological scale

We prove the existence of a spectral resolution of the Wheeler-DeWitt equation when the underlying spacetime is a Friedman universe with flat spatial slices and where the matter fields are comprised of the strong interaction, with \SU(3) replaced by a general \SU(n), $n\ge 2$, and the electro-weak interaction. The wave functions are maps from $\R[4n+10]$ to a subspace of the antisymmetric Fock space, and one noteworthy result is that, whenever the electro-weak interaction is involved, the image of an eigenfunction is in general not one dimensional, i.e., in general it makes no sense specifying a fermion and looking for an eigenfunction the range of which is contained in the one dimensional vector space spanned by the fermion.Comment: 53 pages, v6: some typos correcte

Quantum cosmological Friedman models with a massive Yang-Mills field

We prove the existence of a spectral resolution of the Wheeler-DeWitt equation when the matter field is provided by a massive Yang-Mills field. The resolution is achieved by first solving the free eigenvalue problem for the gravitational field and then the constrained eigenvalue problem for the Yang-Mills field. In the latter case the mass of the Yang-Mills field assumes the role of the eigenvalue.Comment: 16 pages, v3: typos corrected, final version, to appear in CQ

The Starburst Nature of Lyman-Break Galaxies: Testing UV Extinction with X-rays

We derive the bolometric to X-ray correlation for a local sample of normal and starburst galaxies and use it, in combination with several UV reddening schemes, to predict the 2--8 keV X-ray luminosity for a sample of 24 Lyman-break galaxies in the HDF/CDF-N. We find that the mean X-ray luminosity, as predicted from the Meurer UV reddening relation for starburst galaxies, agrees extremely well with the Brandt stacking analysis. This provides additional evidence that Lyman-break galaxies can be considered as scaled-up local starbursts and that the locally derived starburst UV reddening relation may be a reasonable tool for estimating the UV extinction at high redshift. Our analysis shows that the Lyman-break sample can not have far-IR to far-UV flux ratios similar to nearby ULIGs, as this would predict a mean X-ray luminosity 100 times larger than observed, as well as far-IR luminosities large enough to be detected in the sub-mm. We calculate the UV reddening expected from the Calzetti effective starburst attenuation curve and the radiative transfer models of Witt & Gordon for low metallicity dust in a shell geometry with homogeneous or clumpy dust distributions and find that all are consistent with the observed X-ray emission. Finally, we show that the mean X-ray luminosity of the sample would be under predicted by a factor of 6 if the the far-UV is unattenuated by dust.Comment: 7 pages, 3 figures. Accepted for publication in A

Daylight operation of a free space, entanglement-based quantum key distribution system

Many quantum key distribution (QKD) implementations using a free space transmission path are restricted to operation at night time in order to distinguish the signal photons used for a secure key establishment from background light. Here, we present a lean entanglement-based QKD system overcoming that imitation. By implementing spectral, spatial and temporal filtering techniques, we were able to establish a secure key continuously over several days under varying light and weather conditions.Comment: 13 pages, 6 figure

Intensity-dependent loss properties of window materials at 248 nm.

Transmission of fused silica, CaF2, LiF, and MgF2 is measured using 450-fsec, 248-nm pulses in the range 10–120 GW/cm2. Different loss mechanisms such as scattering of transmitted radiation, color-center formation, and multiphoton absorption were studied separately. For fused silica a two-photon absorption mechanism is found, while for CaF2, LiF, and MgF2 three-photon absorption and absorption due to color-center formation are found as dominant absorption mechanisms

Simple method for temporal study of subpicosecond distributed feedback dye lasers.

The spectral and temporal behaviour of subpicosecond DFDLs are studied. A simple and sensitive spectral diagnostic method is proposed to exhibit the presence and determine the temporal separation and relative amplitude of any following pulse. The measurements were performed in a hybrid excimer-dye laser system generating less than 100 fs pulses at 248 nm