Measuring entangled qutrits and their use for quantum bit commitment

We produce and holographically measure entangled qudits encoded in transverse spatial modes of single photons. With the novel use of a quantum state tomography method that only requires two-state superpositions, we achieve the most complete characterization of entangled qutrits to date. Ideally, entangled qutrits provide better security than qubits in quantum bit commitment: we model the sensitivity of this to mixture and show experimentally and theoretically that qutrits with even a small amount of decoherence cannot offer increased security over qubits.     

Measurement of interfluorine distances in solids

(19)F homonuclear dipolar recoupling methods were used to measure internuclear distances ranging from 5 to 12 A in fluorinated organic compounds in the solid state. Magic-angle-spinning-based high-resolution techniques were utilized. Trifluoromethyl and aromatic fluorine groups were separated by rigid aromatic spacers; these compounds were diluted into nonfluorinated host molecule matrices to give isolated homonuclear spin pairs with known internuclear distances. Radiofrequency-driven recoupling (RFDR) was used to elicit magnetization exchange between the spin pairs in 1D and 2D experiments. Simulation of the exchange was accomplished using a Monte Carlo-type algorithm to search the parameter space. These methods allow the determination of distances with an accuracy of 1 A at shorter distances and 2 A at longer distances, with the assumption of no prior knowledge of T(2)(ZQ).     

Atomgewichte

Ohne Zusammenfassung     

Methoden zur Trennung und Bestimmung der Platinmetalle

Ohne Zusammenfassung     

Mit der gewichtsanalytischen Bestimmung von Ruthenium

Ohne Zusammenfassung     

Mixing characteristics of turbulent water vapour jets measured using an isokinetic sampling probe

 Horizontal turbulent water vapour (steam) jets were discharged into ambient air from a circular convergent nozzle under unchoked/choked and saturated/superheated nozzle exit conditions, resulting in two-phase (liquid and vapour), two-fluid (air and water) condensing free jets. Flow properties and mixing characteristics have been measured with the aid of an isokinetic sampling probe arrangement. Radial and axial profiles of air and steam mass flow rates and mass fractions were measured from which entrainment, centreline decay and half-width spreading rates were calculated and compared with data from the literature. Overall, the mixing characteristics of the condensing jets are very similar to those of non-condensing jets extensively reported in the literature. Received: 30 September 1996 / Accepted: 19 May 1997     

Formation of pyrroles from β-chloroazoalkenes and 1,3-dicarbonyl compounds

The azoalkenes (1) have been prepared from the corresponding hydrazones of dichloroacetalhyde; they react with 1,3-dicarbonyl compounds to give first the addition-elimination products (4) and then pyrroles (6).     

An infra-red reflectance microscope — A useful analytical accessory

An infra-red reflectance microscope accessory and several of its analytical applications including Chromatographic fractions and in-situ thin films are described.     

Affinity of a hindered phenol antioxidant for reagents in hydrocarbon media: A low-temperature dielectric relaxation study

Low-temperature dielectric loss measurements reveal a tendency of 4-methyl-2, 6-di-tert-butyl phenol (the antioxidant BHT) to associate with various reagents in hydrocarbon media. The affinity with carbonyl groups appears to be particularly appreciable. It is suggested that this may have a bearing on the antioxidant activity of this type of compound.     

Internal rotation of para-substituted phenols. A low temperature dielectric relaxation study

The dielectric relaxation rates of 18 phenols and 3 thiophenols have been determined in paraffin solutions at 4.2 or 77 K and used to obtain relative values of the tunnel splitting of the ground torsional state. Where comparison is possible the results are compatible with vapour phase microwave spectroscopic data. The barriers to hydroxyl rotation are calculated and are fairly consistent with barriers derived from far infrared data. Para-substituents F, CH₃, Cl, C(CH₃)₃, Br and I in order of decreasing effectiveness, lower the barrier. COOH and CHO raise it by 350–400 cm^?1.