473 research outputs found
Entanglement formation and violation of Bell's inequality with a semiconductor single photon source
We report the generation of polarization-entangled photons, using a quantum
dot single photon source, linear optics and photodetectors. Two photons created
independently are observed to violate Bell's inequality. The density matrix
describing the polarization state of the postselected photon pairs is also
reconstructed, and agrees well with a simple model predicting the quality of
entanglement from the known parameters of the single photon source. Our scheme
provides a method to generate no more than one entangled photon pair per cycle,
a feature useful to enhance quantum cryptography protocols using entangled
photons.Comment: 4 pages, 3 figures, submitted to PR
Binding or aggregation? Hazards of interpretation in studies of molecular recognition by porphyrins in water
Reports suggest that polar porphyrins can serve as carbohydrate receptors in water. Addition of glucose to TPPS (shown) does cause changes in UV-visible absorption. However, these are best explained by altered aggregation states and not by formation of a closely-bound complex.</p
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First photosensitized enantiodifferentiating isomerization by optically active sensitizer immobilized in zeolite supercages
Enantiodifferentiating photoisomerization of (Z)-cyclooctene sensitized by (R)- or (S)-1-methylheptyl benzoate immobilized in zeolite supercages afforded the respective enantiomer pair, (—)- and (+)-(E)-isomer (1E) in 5% enantiomeric excess, whilst racemic 1E was obtained upon homogeneous-phase photosensitization with the same antipodal sensitizer pair, thus demonstrating for the first time that chirally modified zeolites not only serve as supramolecular photosensitizing media but also enhance the original enantiodifferentiating ability of chiral photosensitizer
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Stereoselective E/Z photoisomerization of oxazolidinone functionalized enecarbamates: direct and triplet sensitized irradiation
Oxazolidinone-functionalized enecarbamates undergo diastereoselective E/Z photoisomerization upon direct and triplet sensitized irradiations with chiral/achiral sensitizers, showing that the enhanced product diastereoselectivity depends on the solvent and temperature
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