Demonstration of a simple entangling optical gate and its use in bell-state analysis

We demonstrate a new architecture for an optical entangling gate that is significantly simpler than previous realizations, using partially polarizing beam splitters so that only a single optical mode-matching condition is required. We demonstrate operation of a controlled-z gate in both continuous-wave and pulsed regimes of operation, fully characterizing it in each case using quantum process tomography. We also demonstrate a fully resolving, nondeterministic optical Bell-state analyzer based on this controlled-z gate. This new architecture is ideally suited to guided optics implementations of optical gates.

Greenberger-Horne-Zeilinger-type and W-type entangled coherent states: Generation and Bell-type inequality tests without photon counting

We study Greenberger-Horne-Zeilinger-type (GHZ-type) and W-type three-mode entangled coherent states. Both types of entangled coherent states violate Mermin's version of the Bell inequality with threshold photon detection (i.e., without photon counting). Such an experiment can be performed using linear optics elements and threshold detectors with significant Bell violations for GHZ-type entangled coherent states. However, to demonstrate Bell-type inequality violations for W-type entangled coherent states, additional nonlinear interactions are needed. We also propose an optical scheme to generate W-type entangled coherent states in free-traveling optical fields. The required resources for the generation are a single-photon source, a coherent state source, beam splitters, phase shifters, photodetectors, and Kerr nonlinearities. Our scheme does not necessarily require strong Kerr nonlinear interactions; i.e., weak nonlinearities can be used for the generation of the W-type entangled coherent states. Furthermore, it is also robust against inefficiencies of the single-photon source and the photon detectors.

Better Bell-inequality violation by collective measurements

The standard Bell-inequality experiments test for violation of local realism by repeatedly making local measurements on individual copies of an entangled quantum state. Here we investigate the possibility of increasing the violation of a Bell inequality by making collective measurements. We show that the nonlocality of bipartite pure entangled states, quantified by their maximal violation of the Bell-Clauser-Horne inequality, can always be enhanced by collective measurements, even without communication between the parties. For mixed states we also show that collective measurements can increase the violation of Bell inequalities, although numerical evidence suggests that the phenomenon is not common as it is for pure states.

Mechanical vibration characteristics of bell-type pump maintings

This thesis describes an analytical and experimental study to determine the mechanical characteristics of the pump mounting, bell housing type. For numerical purposes, the mount was modelled as a thin circular cylindrical shell with cutouts, stiffened with rings and stringers; the boundary conditions were considered to be either clamped-free or clamped-supporting rigid heavy mass. The theoretical study was concerned with both the static response and the free vibration characteristics of the mount. The approach was based on the Rayleigh-Ritz approximation technique using beam characteristic (axial) and trigonometric (Circumferential) functions in the displacement series, in association with the Love - Timoshenko thin shell theory. Studies were carried out to determine the effect of the supported heavy mass on the static response, frequencies and mode shapes; in addition, the effects of stringers, rings and cutouts on vibration characteristics were investigated. The static and dynamic formulations were both implemented on the Hewlett Packard 9845 computer. The experimental study was conducted to evaluate the results of the natural frequencies and mode shapes, predicted numerically. In the experimental part, a digital computer was used as an experiment controller, which allowed accurate and quick results. The following observations were made: 1. Good agreements were obtained with the results of other investigators. 2. Satisfactory agreement was achieved between the theoretical and experimental results. 3. Rings coupled the axial modal functions of the plain cylinder and tended to increase frequencies, except for the torsion modes where frequencies were reduced. Stringers coupled the circumferential modal functions and tended to decrease frequencies. The effect of rings was stronger than that of stringers. 4. Cutouts tended to reduce frequencies; in general, but this depends on the location of the cutouts; if they are near the free edge then an increase in frequencies is obtained. Cutouts coupled both axial and circumferential modal functions. 5. The supported heavy mass had similar effects to those of the rings, but in an exaggerated manner, particularly in the reduction of torsion frequencies. 6. The method of analysis was found to be a convenient analytical tool for estimating the overall behaviour of the shell with cutouts.

Research of the Acoustic Characteristics of the Bell "Mazepa" of the Sofia Cathedral (Kiev) and their Comparison with Characteristics of Bulgarian Bells

Experimental researches of one of the eldest bells («Mazepa»-see Appendix1) in Ukraine, are considered in the article. The spectra and spectra- time analysis of bell ringing is embodied, main frequencies of oscillation and musical intervals of sounding are determined. Comparative description of bell sounding with the known bells of Russia and Bulgaria is given.

Aszimmetriák az Európai Unión belül (Assimetries within the European Union)

A centrum-periféria kapcsolatok elemzése az Európai Unióra is kiterjeszthető. Az integrációs folyamatban jól elemezhetőek a bourdeiu-i tőkeformák, ezek egymásra történő átváltása, a gazdasági és politikai aszimmetriák kölcsönhatása. E kölcsönös kapcsolatokban továbbra is a gazdasági viszonyok meghatározottsága érvényesül. A világgazdasági válság felszínre hozta a történelmi aszimmetriákat, amelyeket a korábbi neoliberális politikák tovább mélyítettek. Az Unión belüli periferális térségekre a válság különbözőképpen hatott. E hatások semlegesítésére többnyire a megszorító gazdaságpolitikákat alkalmazzák. Továbbra is hiányzik azonban egy, a minőségi s nem mennyiségi szempontokat hangsúlyozó fejlesztési politika. Egy ilyen megközelítés a strukturális, intézményi vonatkozásokat erősítené, s ezzel járulna hozzá a periféria termelési, forgalmi, elosztási képességeinek fokozásához. _____ Analysis of centre-periphery relations can be extended to the European Union as well. The capital forms by Bourdieu, their inter-changeability, mutual effects of economic and political asymmetries could be analysed well in the integration process. In these mutual relations economic relations still play the dominant role. The global economic crisis has brought to the surface historical asymmetries, further aggravated by earlier neo-liberal economic policies. Peripheral regions within the Union have been affected in different ways. In order to neutralise these effects austerity measure have been implemented. However, a development policy, emphasising quality and not only quantitative aspects, is still missing. Such an approach would strengthen structural and institutional elements, further enhancing production, trade, and distribution capabilities of the periphery.

Mike Heithaus' field crew sets out a longline that has about 40 small hooks baited with mullett. They let the line soak for an hour before they check for sharks, Shark River

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. This image is made available for non-commercial or educational use only.