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Orbital angular momentum entangled photons emitted by a down-conversion source are in higher dimensional entangled states. Here we report the experimental confirmation by demonstrating a violation of a generalized Clauser-Horne-Shimony-Holt-type Bell inequality in three dimensions by more than 18 standard deviations. Higher dimensional entangled states allow the realization of new types of quantum communication protocols. They also provide a more secure quantum cryptography scheme. Therefore our experimental results are likely to have applications in future quantum communication technology. 相似文献
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Molina-Terriza G Vaziri A Rehácek J Hradil Z Zeilinger A 《Physical review letters》2004,92(16):167903
A general protocol in quantum information and communication relies in the ability of producing, transmitting, and reconstructing, in general, qunits. In this Letter we show for the first time the experimental implementation of these three basic steps on a pure state in a three-dimensional space, by means of the orbital angular momentum of the photons. The reconstruction of the qutrit is performed with tomographic techniques and a maximum-likelihood estimation method. For the tomographic reconstruction we used more than 2400 different projections. In this way we also demonstrate that we can perform any transformation in the three-dimensional space. 相似文献
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Enhancement of entanglement is necessary for most quantum communication protocols many of which are defined in Hilbert spaces larger than 2. In this work we present the experimental realization of entanglement concentration of orbital angular momentum entangled photons. We investigate the specific case of three dimensions and the possibility of generating different entangled states out of an initial state. The results presented here are of importance for pure states as well as for mixed states. 相似文献
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Equilibrium geometry of the heterofullerene C16N12 is calculated at the Density Functional Theory level and further compared with that of fullerene C28. Theoretical vibrational spectra as well as the infrared intensities and Raman activities are reported. In addition, the effect of N substitution on fullerene stability is investigated in comparison to exohedral complexes C28Cl4 and C16N12Cl4. The results show that C16N12 is stabilized by strengthening the hexagon belts, while exohedral complexes stabilize the hexagon structure. 相似文献
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M. Rahimpour M. Soheili N. Eslami A. Fayaz S. Sardari B. Vaziri 《Chromatographia》2007,66(1-2):133-136
Two-dimensional electrophoresis is a current method for separating complex protein mixtures of a given sample in different
states. In this study an improved carrier ampholyte isoelectric focusing method has been evaluated for its capacity for preliminary
screening of expressional proteomics subjects. In comparison with current carrier ampholyte isoelectric focusing, this method
showed enough resolution power to display major expressional changes in proteomic samples and demonstrated it can be used
as a substitution for the immobiline based isoelectric focusing method. 相似文献
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Andersen MF Ryu C Cladé P Natarajan V Vaziri A Helmerson K Phillips WD 《Physical review letters》2006,97(17):170406
We demonstrate the coherent transfer of the orbital angular momentum of a photon to an atom in quantized units of variant Planck's over 2pi, using a 2-photon stimulated Raman process with Laguerre-Gaussian beams to generate an atomic vortex state in a Bose-Einstein condensate of sodium atoms. We show that the process is coherent by creating superpositions of different vortex states, where the relative phase between the states is determined by the relative phases of the optical fields. Furthermore, we create vortices of charge 2 by transferring to each atom the orbital angular momentum of two photons. 相似文献
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S.A. Vaziri H.R. Shahverdi M.J. Torkamany S.G. Shabestari 《Optics and Lasers in Engineering》2009,47(9):971-975
Experimental investigations were carried out to examine the influence of the spot size and peak-power density of a pulsed Nd:YAG laser on the depth of the alloyed layer, the microstructure and the hardness in laser surface alloying of Al with Ni. It was found that the effect of both the peak-power density and the amount of energy absorbed from the laser beam on the depth of the alloyed layer and hardness must be considered simultaneously. In this work, the hardness of the alloyed layer was found to be 10–15 times the value for base Al. 相似文献
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Rizzieri R Mahadevan L Vaziri A Donald A 《Langmuir : the ACS journal of surfaces and colloids》2006,22(8):3622-3626
When a thin film of initially hydrated gelatin is allowed to dry from the surface, superficial changes in the structure of the material affect the local mechanical properties of the drying region. If the film is simultaneously subjected to large strain deformation (above 20%), a periodic pattern of wrinkles appears on the surface of the gelatin along the length of the sample in the direction of the applied force. These wrinkles are uniformly distributed on the surface of the gelatin with a wavelength that is much smaller than the sample thickness, which changes with sample composition, aging time, and deformation rate. We investigate these patterns via in situ environmental scanning electron microscopy (ESEM) and provide a theory for their origin. 相似文献