173 research outputs found

    Photon polarization entanglement induced by biexciton: experimental evidence for violation of Bell's inequality

    Get PDF
    We have investigated the polarization entanglement between photon pairs generated from a biexciton in a CuCl single crystal via resonant hyper parametric scattering. The pulses of a high repetition pump are seen to provide improved statistical accuracy and the ability to test Bell's inequality. Our results clearly violate the inequality and thus manifest the quantum entanglement and nonlocality of the photon pairs. We also analyzed the quantum state of our photon pairs using quantum state tomography.Comment: 4 pages, 5 figure

    Quantum diffraction and interference of spatially correlated photon pairs and its Fourier-optical analysis

    Full text link
    We present one- and two-photon diffraction and interference experiments involving parametric down-converted photon pairs. By controlling the divergence of the pump beam in parametric down-conversion, the diffraction-interference pattern produced by an object changes from a quantum (perfectly correlated) case to a classical (uncorrelated) one. The observed diffraction and interference patterns are accurately reproduced by Fourier-optical analysis taking into account the quantum spatial correlation. We show that the relation between the spatial correlation and the object size plays a crucial role in the formation of both one- and two-photon diffraction-interference patterns.Comment: 10 pages, 13 figures, rev.

    Centrifuge Model Tests of Tieback Anchors and Drainage Pipes for Stabilization of Slopes under Earthquake Loads

    Get PDF
    Tieback anchors are widely used for the stabilization of natural and manmade slopes in Japan. The interactions between tieback anchors and slopes under seismic loading need to be understood to develop rational design concepts and installation methods in earthquake prone areas. We conducted centrifuge model tests to examine the characteristics of dynamic and residual loads on tieback anchors installed in slopes subjected to seismic loads. If the model slope contained a saturated zone, circular failure occurred even with pre-tensioned tieback anchors, and the amplitude of the oscillating loads on the tieback anchors was very high. This suggested that excess pore water pressure may cause the design capacity of the anchors to be exceeded, depending on the stability of the slope and intensity of the earthquake. Additional tests were therefore conducted with model slopes with drainage pipes installed (perforated plastic tubes). The drainage pipes significantly reduced pore water pressure, which in turn enhanced the stability of the slope and reduced the loads on the tieback anchors. We conclude that installation of drainage pipes in earthfill slopes would enable the selection of smaller ground anchors and potentially reduce overall construction costs

    Induction of embryonal carcinoma cell differentiation by deferoxamine, a potent therapeutic iron chelator

    Get PDF
    AbstractWe investigated the effects of deferoxamine on the differentiation of embryonal carcinoma F9 cells. Deferoxamine, a widely used therapeutic agent for thalassemia and iron overload, was found to induce F9 cell differentiation and to have some unique characteristics compared with other chelators, hinokitiol and dithizone, which were previously reported to induce differentiation of these cells. This hydrophilic agent induced reversible differentiation as did sodium butyrate, whereas other chelators did not. However, morphological features of the cells after deferoxamine-induced differentiation were similar to those of cells incubated with the other chelators. The differentiation-inducing activity of deferoxamine was abolished by preincubation with Fe3+ ions, similarly to the other chelators examined. Moreover, cell proliferation was inhibited by treatment with this agent, and the numbers of cells in the colonies were reduced by apoptosis. Based on these results, we conclude that deferoxamine induces differentiation and apoptosis of F9 cells via chelation of extracellular and/or intracellular Fe3+ ions

    Quantum diffraction and interference of spatially correlated photon pairs generated by spontaneous parametric down-conversion

    Full text link
    We demonstrate one- and two-photon diffraction and interference experiments utilizing parametric down-converted photon pairs (biphotons) and a transmission grating. With two-photon detection, the biphoton exhibits a diffraction-interference pattern equivalent to that of an effective single particle that is associated with half the wavelength of the constituent photons. With one-photon detection, however no diffraction-interference pattern is observed. We show that these phenomena originate from the spatial quantum correlation between the down-converted photons.Comment: 4 pages, 5 figure
    corecore