Evaluation of the Immigrant Citizens Survey (ICS)

This evaluation undertakes a critical appraisal of the "Immigrant Citizens Survey (ICS)". The survey was funded under the European Integration Fund and jointly coordinated by the King Baudouin Foundation (KBF) and the Migration Policy Group (MPG). The survey was implemented in cooperation with research, polling and launch partners in the 7 countries covered by the survey. The survey was implemented in 2011 and 2012 and launched in May 2012

Strong atom-field coupling for Bose-Einstein condensates in an optical cavity on a chip

An optical cavity enhances the interaction between atoms and light, and the rate of coherent atom-photon coupling can be made larger than all decoherence rates of the system. For single atoms, this strong coupling regime of cavity quantum electrodynamics (cQED) has been the subject of spectacular experimental advances, and great efforts have been made to control the coupling rate by trapping and cooling the atom towards the motional ground state, which has been achieved in one dimension so far. For N atoms, the three-dimensional ground state of motion is routinely achieved in atomic Bose-Einstein condensates (BECs), but although first experiments combining BECs and optical cavities have been reported recently, coupling BECs to strong-coupling cavities has remained an elusive goal. Here we report such an experiment, which is made possible by combining a new type of fibre-based cavity with atom chip technology. This allows single-atom cQED experiments with a simplified setup and realizes the new situation of N atoms in a cavity each of which is identically and strongly coupled to the cavity mode. Moreover, the BEC can be positioned deterministically anywhere within the cavity and localized entirely within a single antinode of the standing-wave cavity field. This gives rise to a controlled, tunable coupling rate, as we confirm experimentally. We study the heating rate caused by a cavity transmission measurement as a function of the coupling rate and find no measurable heating for strongly coupled BECs. The spectrum of the coupled atoms-cavity system, which we map out over a wide range of atom numbers and cavity-atom detunings, shows vacuum Rabi splittings exceeding 20 gigahertz, as well as an unpredicted additional splitting which we attribute to the atomic hyperfine structure.Comment: 20 pages. Revised version following referees' comments. Detailed notes adde

Fiber Fabry-Perot cavity with high finesse

We have realized a fiber-based Fabry-Perot cavity with CO2 laser-machined mirrors. It combines very small size, high finesse F>=130000, small waist and mode volume, and good mode matching between the fiber and cavity modes. This combination of features is a major advance for cavity quantum electrodynamics (CQED), as shown in recent CQED experiments with Bose-Einstein condensates enabled by this cavity [Y. Colombe et al., Nature 450, 272 (2007)]. It should also be suitable for a wide range of other applications, including coupling to solid-state emitters, gas detection at the single-particle level, fiber-coupled single-photon sources and high-resolution optical filters with large stopband.Comment: Submitted to New J. Phys

Bose-Einstein condensate coupled to a nanomechanical resonator on an atom chip

We theoretically study the coupling of Bose-Einstein condensed atoms to the mechanical oscillations of a nanoscale cantilever with a magnetic tip. This is an experimentally viable hybrid quantum system which allows one to explore the interface of quantum optics and condensed matter physics. We propose an experiment where easily detectable atomic spin-flips are induced by the cantilever motion. This can be used to probe thermal oscillations of the cantilever with the atoms. At low cantilever temperatures, as realized in recent experiments, the backaction of the atoms onto the cantilever is significant and the system represents a mechanical analog of cavity quantum electrodynamics. With high but realistic cantilever quality factors, the strong coupling regime can be reached, either with single atoms or collectively with Bose-Einstein condensates. We discuss an implementation on an atom chip.Comment: published version (5 pages, 3 figures

Fremdenrecht, soziale Diskriminierung und Integration: die schwierige Situation der ehemaligen "GastarbeiterInnen" und ihres Familiennachzugs

"Der Beitrag untersucht, inwiefern fremdenrechtliche Regelungen und Diskriminierungserfahrungen die subjektiv wahrgenommene Integration der ehemaligen 'GastarbeiterInnen' und ihres Familiennachzugs beeinflussen. Der Beitrag basiert auf Ergebnissen einer Erhebung, die 2006 durchgeführt wurde. Dafür wurden 108 MigrantInnen aus dem ehemaligen Jugoslawien und der Türkei, die seit mindestens zehn Jahren in Österreich leben und bei der Einreise zumindest zehn Jahre alt waren, schriftlich über ihre Erfahrungen mit dem österreichischen Fremdenrecht, über Diskriminierungserfahrungen sowie Integration befragt. Die Befragung zeigt, dass sich Diskriminierungserfahrungen und eine negative Einschätzung des Fremdenrechts signifikant negativ auf die subjektiv wahrgenommene Integration von MigrantInnen in Österreich auswirken. Die Einbürgerung wird von den Befragten eher als praktisches Instrument gesehen, um mehr Rechte zu erhalten." (Autorenreferat)"The article examines the relationship between migration law, discrimination experiences and the subjectively perceived integration of the former 'guest-workers' and their family reunion in Austria. The presented analysis is based on paper-and-pencil interviews with 108 immigrants from former Yugoslavia and Turkey, conducted in 2006. These persons have stayed in Austria for at least ten years and had a minimum age of ten at the time of entry. The survey shows that discrimination experiences and a negative assessment of the Austrian migration law exercised a negative impact on the subjective (personal) perception of integration by the migrants. Naturalization is being mainly considered as a practical tool for obtaining additional rights." (author's abstract

Resonant coupling of a Bose-Einstein condensate to a micromechanical oscillator

We report experiments in which the vibrations of a micromechanical oscillator are coupled to the motion of Bose-condensed atoms in a trap. The interaction relies on surface forces experienced by the atoms at about one micrometer distance from the mechanical structure. We observe resonant coupling to several well-resolved mechanical modes of the condensate. Coupling via surface forces does not require magnets, electrodes, or mirrors on the oscillator and could thus be employed to couple atoms to molecular-scale oscillators such as carbon nanotubes.Comment: 9 pages, 4 figure

A scanning cavity microscope

Imaging the optical properties of individual nanosystems beyond fluorescence can provide a wealth of information. However, the minute signals for absorption and dispersion are challenging to observe, and only specialized techniques requiring sophisticated noise rejection are available. Here we use signal enhancement in a high-finesse scanning optical microcavity to demonstrate ultra-sensitive imaging. Harnessing multiple interactions of probe light with a sample within an optical resonator, we achieve a 1, 700-fold signal enhancement compared with diffraction-limited microscopy. We demonstrate quantitative imaging of the extinction cross-section of gold nanoparticles with a sensitivity less than 1 nm(2);we show a method to improve the spatial resolution potentially below the diffraction limit by using higher order cavity modes, and we present measurements of the birefringence and extinction contrast of gold nanorods. The demonstrated simultaneous enhancement of absorptive and dispersive signals promises intriguing potential for optical studies of nanomaterials, molecules and biological nanosystems