Echelle Spectroscopy of gamma-ray binary 1FGL J1018.6-5856

We observed the Fermi-discovered gamma-ray binary 1FGL J1018.6-5856 at 20 epochs over 50 days using the CHIRON spectrograph, obtaining spectra at R~25,000 covering 4090-8908A. The average spectrum confirms an O6 V((f)) spectral type and extinction E(B-V) = 1.35+/-0.04. Variable absorption line equivalent widths suggest substantial contamination by wind line features. The limited S/N ratio hindered accurate continuum definition and prevented measurement of a high quality radial velocity curve. Nevertheless, the best data indicate a radial velocity amplitude <40 km/s for the He II lines and substantially lower for H I. We argue that this indicates a most likely compact object mass <2.2Msun. While black hole solutions are not excluded, a neutron star source of the gamma-ray emission seems preferred.Comment: 5 figures. To appear in the Astrophysical Journa

Abraham Abulafia's Esotericism: Secrets and Doubt

This book focuses on Abraham Abulafia's esoteric thought in relation to Maimonides, Maimonideans, and Islamic thought in the line of Leo Strauss' theory of the history of philosophy. A survey of Abulafia's sources leads into an analysis of the esoteric meaning on the famous parable of the three rings, considering also the possible connection between this parable, which Abdulafia inserted into a book dedicated to his student, the 13th century rabbi Nathan the wise, and the Lessing's Play Nathan the Wise. The book also examines Abulafia's universalistic understanding of the nature of the Bible, the Hebrew language, and the people of Israel (or the Sinaic revelation). The universal aspects of Abulafia’s thought have been put in relief against the more widespread Kabbalistic views which are predominantly particularistic. A number of texts have also been identified here for the first time as authored by Abulafia

Entanglement For Atom Interferometers

Quantum Sensors, like atom interferometers (AI), can be employed for high-precision measurements of inertial forces, including their application as gravimeters, gradiometers, accelerometers, and gyroscopes. Their measurement principle relies on ultracold atoms that are prepared in quantum-mechanical superposition states in external degrees of freedom. These states can be prepared by a momentum transfer of a Raman laser. Then the superposition state senses the effect of an inertial force, which induce a corresponding relative phase. The phase is read out by a final coupling which converts the interferometric phase into a atom number difference between the two states. The difference provides an estimate of the interferometric phase and the corresponding quantity of interest. The quantum mechanical noise of the atomic ensemble cause a fundamental uncertainty of this estimation, which I analyze for generic AIs. For small atomic densities, the quantum phase noise of the ensemble limits the interferometric sensitivity. For large densities, quantum number fluctuations generate density fluctuations, which generates phase noise. I show that these two competing effects result in an optimal atom number with a maximal interferometer resolution. Squeezed atomic samples allow for a reduction of the quantum noise of one quantity at the expense of an increased noise along of a conjugate quantity. Phase and number are such quantities which obey to a variant of Heisenberg’s uncertainty principle. Neither phase nor number squeezing can improve the maximal interferometer resolution. As one main result of this thesis, I show how an optimal squeezing in between number and phase squeezing, allows for a fundamental improvement. I evaluate possible experimental paths to implement the proposed protocol. Concepts for a squeezing-enhanced operation of external-degree AIs have not yet been demonstrated. I propose and implement an atomic gravimeter, which is designed to accept spin-squeezed atomic states as input states. The interferometer is designed such that the interferometer couplings are performed in spin space, while the phase accumulation is performed in momentum states. For this interferometer, the squeezed input can be directly obtained from spin dynamics in spinor Bose-Einstein condensates. The main noise contributions in the experiment are analyzed, which results in a factor of 84 above the relevant quantum limit, preventing a squeezing enhancement so far. I outline a suppression of the main noise source, uncontrolled AC Stark shift on the squeezed mode and propose future important applications, including test of spontaneous collapse theories and an improvement of large-scale, high-precision gradiometers

Dignitates and Kavod:

Abstract not availabl

Heinz-Günter Holtappels, Eckhard Klieme, Thomas Rauschenbach, Ludwig Stecher (Hrsg.) : Ganztagsschule in Deutschland. Ergebnisse der Ausgangserhebung der "Studie zur Entwicklung von Ganztagsschulen" (StEG), Juventa-Verlag, Weinheim und München 2007, 398 S., ISBN 978-3-7799-2150-9. [Rezension]

Rezension von: Heinz-Günter Holtappels, Eckhard Klieme, Thomas Rauschenbach, Ludwig Stecher (Hrsg.): Ganztagsschule in Deutschland. Ergebnisse der Ausgangserhebung der "Studie zur Entwicklung von Ganztagsschulen" (StEG). (DIPF/Orig.

Fritz Bohnsack: Schule – Verlust oder Stärkung der Person? Bad Heilbrunn: Klinkhardt 2008. 182 S., EUR 18,90 [Rezension]

Rezension zu: Fritz Bohnsack: Schule –Verlust oder Stärkung der Person? Bad Heilbrunn: Klinkhardt 2008. 182 S., EUR 18,9