TY - JOUR A1 - Egbe, D. A. M. A1 - Carbonnier, B. A1 - Paul, E. L. A1 - Muhlbacher, D. A1 - Kietzke, Thomas A1 - Birckner, Eckhard A1 - Neher, Dieter A1 - Grummt, U. W. A1 - Pakula, T. T1 - Diyne-containing PPVs : Solid-state properties and comparison of their photophysical and electrochemical properties with those of their Yne-containing counterparts N2 - Diyne-containing poly(p-phenylene-vinylene)s, 4a-d, of general chemical structure-(Ph-C&3bond; C-C&3bond; C-Ph- CH&3bond; CH-Ph-CH&3bond; CH-)(n), obtained through polycondensation reactions of 1,4-bis(4-formyl-2,5-dioctyloxyphenyl)- buta-1,3-diyne (2) with various 2,5-dialkoxy-p-xylylenebis(diethylphosphonates), 3a-d, are the subject of this report. The polymers exhibit great disparity in their degree of polymerization, n, which might be ascribed to side-chain-related differences in reactivity of the reactive species during the polycondensation process and which led to n-dependent absorption (solution and solid state) and emission (solution) behaviors of the polymers. Polarizing optical microscopy and differential scanning calorimetry are employed to probe their thermal behavior. The structure is investigated by means of wide-angle X-ray diffraction for both isotropic and macroscopically oriented samples. Comparison of photophysical (experimental and theoretical) and electrochemical properties of the polymers with those of their yne- containing counterparts 6a-d [-(Ph-C&3bond; C-Ph-CH&3bond; CH-Ph-CH&3bond; CH-)(n)] has been carried out. Similar photophysical behavior was observed for both types of polymers despite the difference in backbone conjugation pattern. The introduction of a second yne unit in 4 lowers the HOMO and LUMO levels, thereby enhancing the electron affinity of polymers 4 compared to polymers 6. The "wider opening" introduced by the second yne unit facilitates moreover the movement of charges during the electrochemical processes leading to minimal discrepancy, Delta E-g between the optical and electrochemical band gap energies. Polymers 6, in contrast, show significant side-chain-dependent Delta E-g values. Low turn-on voltages between 2 and 3 V and maximal luminous efficiencies between 0.32 and 1.25 cd/A were obtained from LED devices of configuration ITO/PEDOT:PSS/polymer 4/Ca/Al Y1 - 2005 SN - 0024-9297 ER - TY - JOUR A1 - Eisert, Jens A1 - Cramer, Marcus T1 - Single-copy entanglement in critical quantum spin chains N2 - We consider the single-copy entanglement as a quantity to assess quantum correlations in the ground state in quantum many-body systems. We show for a large class of models that already on the level of single specimens of spin chains, criticality is accompanied with the possibility of distilling a maximally entangled state of arbitrary dimension from a sufficiently large block deterministically, with local operations and classical communication. These analytical results-which refine previous results on the divergence of block entropy as the rate at which maximally entangled pairs can be distilled from many identically prepared chains-are made quantitative for general isotropic translationally invariant spin chains that can be mapped onto a quasifree fermionic system, and for the anisotropic XY model. For the XX model, we provide the asymptotic scaling of similar to(1/6)log(2)(L), and contrast it with the block entropy Y1 - 2005 ER - TY - JOUR A1 - Serafini, A. A1 - Eisert, Jens A1 - Wolf, M. M. T1 - Multiplicativity of maximal output purities of Gaussian channels under Gaussian inputs N2 - We address the question of the multiplicativity of the maximal p-norm output purities of bosonic Gaussian channels under Gaussian inputs. We focus on general Gaussian channels resulting from the reduction of unitary dynamics in larger Hilbert spaces. It is shown that the maximal output purity of tensor products of single-mode channels under Gaussian inputs is multiplicative for any p is an element of (1, infinity) for products of arbitrary identical channels as well as for a large class of products of different channels. In the case of p=2, multiplicativity is shown to be true for arbitrary products of generic channels acting on any number of modes Y1 - 2005 ER - TY - JOUR A1 - Dines, Nicoleta A1 - Schulze, Bert-Wolfgang T1 - Mellin-edge representations of elliptic operators N2 - We construct a class of elliptic operators in the edge algebra on a manifold M with an embedded submanifold Y interpreted as an edge. The ellipticity refers to a principal symbolic structure consisting of the standard interior symbol and an operator-valued edge symbol. Given a differential operator A on M for every (sufficiently large) s we construct an associated operator A(s) in the edge calculus. We show that ellipticity of A in the usual sense entails ellipticity of A(s) as an edge operator (up to a discrete set of reals s). Parametrices P of A then correspond to parametrices P-s of A(s) interpreted as Mellin-edge representations of P. Copyright (c) 2005 John Wiley & Sons, Ltd Y1 - 2005 SN - 0170-4214 ER - TY - JOUR A1 - Dimitriev, O. P. A1 - Smertenko, P. S. A1 - Stiller, Burkhard A1 - Brehmer, Ludwig T1 - Polyaniline-transition metal salt complexes: insight into formation mechanisms N2 - Two basic morphologies of emeraldine base of polyaniline-transition metal salt complex films cast from N- methylpyrrolidinone solutions are described. The first morphology consists of grains and the other consists of loose aggregates, respectively. The correlation of the film morphology with formation of precipitate in the complex solution, kinetics of solvent evaporation from the cast film, amount of solvent entrapped in the film, film conductivity, and IR absorption spectra is shown. Two different mechanisms of the complex formation as a result of competition in the polymer- inorganic salt-solvent trio interactions are discussed; the first mechanism results in folding of macromolecules into compact coils being then a core of grains in the complex films, and the second mechanism leads to blending of the polymer chains with solvent giving rise to formation of loose aggregates. (c) 2005 Elsevier B.V. All rights reserved Y1 - 2005 SN - 0379-6779 ER - TY - JOUR A1 - Dikovsky, V. A1 - Japha, Y. A1 - Henkel, Carsten A1 - Folman, R. T1 - Reduction of magnetic noise in atom chips by material optimization N2 - We discuss the influence of the material type in metal wires to the electromagnetic fluctuations in magnetic microtraps close to the surface of an atom chip. We show that significant reduction of the magnetic noise can be achieved by replacing the pure noble metal wires with their dilute alloys. The alloy composition provides an additional degree of freedom which enables a, controlled reduction of both magnetic noise and resistivity if the atom chip is cooled. In addition, we provide a careful re-analysis of the magnetically induced trap loss observed by Yu-Ju Lin et al. [Phys. Rev. Lett. 92 050404 (2004)] and find good agreement with an improved theory Y1 - 2005 ER - TY - JOUR A1 - Franco, Olga A1 - Orgzall, Ingo A1 - Reck, Günter A1 - Stockhause, Sabine A1 - Schulz, Burkhard T1 - Structure and high-pressure behavior of 2,5-di-(4-aminophenyl)-1,3,4-oxadiazole N2 - The crystalline structures of two modifications of a compound containing the oxadiazole ring, 2,5-di-(4- aminophenyl)-1,3,4-oxadiazole (DAPO) were determined. One of these modifications contains water molecules in the crystal structure, which is observed for the first time for an oxadiazole crystal. Both crystals show an orthorhombic structure. The water free modification, DAPO L belongs to the space group Pbca (61) and has the lattice parameters: a = 13.461(5), b = 7.937(3) and c = 22.816(8) angstrom (CCDC 246608). The water containing pseudo-polymorph, DAPO 11, has the space group Cmcm (63) and the lattice parameters: a = 16.330(5), b = 12.307(2) and c = 6.9978(14) angstrom (CCDC 246609). To gain information on the inter molecular interactions within the crystals, X-ray experiments under compression at ambient temperature and under heating at vacuum conditions were performed. Neither DAPO I nor DAPO II undergo phase transitions in the ressure range up to 5 GPa, as could be concluded from X-ray and Raman experiments. X-ray and calorimetric studies indicate that DAPO II dehydrates into DAPO I under increasing temperature. Structural considerations suggest a two-stage process. The compression behavior of both substances is well described by the Murnaghan equation of state (MEOS) and the values of the bulk modulus and its pressure derivative are determined for these crystals. Additionally, in the case of DAPO I, also the thermal expansion coefficient an was measured. (c) 2005 Elsevier Ltd. All rights reserved Y1 - 2005 SN - 0022-3697 ER - TY - JOUR A1 - Cirone, M. A. A1 - Negretti, Antonio A1 - Calarco, T. A1 - Krüger, P. A1 - Schmiedmayer, Jörg T1 - A simple quantum gate with atom chips N2 - We present a simple scheme for implementing an atomic phase gate using two degrees of freedom for each atom and discuss its realization with cold rubidium atoms on atom chips. We investigate the performance of this collisional phase gate and show that gate operations with high fidelity can be realized in magnetic traps that are currently available on atom chips Y1 - 2005 ER - TY - JOUR A1 - Christensen, Lise Bech A1 - Schulte-Ladbeck, R. E. A1 - Sanchez, Sebastian F. A1 - Becker, Thomas A1 - Jahnke, Knud A1 - Kelz, A. A1 - Roth, Martin M. A1 - Wisotzki, Lutz T1 - Abundances and kinematics of a candidate sub-damped Lymana galaxy toward PHL 1226 N2 - The spectrum of the quasar PHL 1226 is known to have a strong Mg II and sub-damped Lymanalpha (sub-DLA) absorption line system with N(H I) = (5 +/- 2) x 10(19) cm(-2) at z = 0.1602. Using integral field spectra from the Potsdam Multi Aperture Spectrophotometer (PMAS) we investigate a galaxy at an impact parameter of 6".4 which is most probably responsible for the absorption lines. A fainter galaxy at a similar redshift and a slightly larger distance from the QSO is known to exist, but we assume that the absorption is caused by the more nearby galaxy. From optical Balmer lines we estimate an intrinsic reddening consistent with 0, and a moderate star formation rate of 0.5 M-circle dot yr(-1) is inferred from the Ha luminosity. Using nebular emission line ratios we find a solar oxygen abundance 12 + log (O/H) = 8.7 +/- 0.1 and a solar nitrogen to oxygen abundance ratio log (N/O) = -1.0 +/- 0.2. This abundance is larger than those of all known sub-DLA systems derived from analyses of metal absorption lines in quasar spectra. On the other hand, the properties are compatible with the most metal rich galaxies responsible for strong Mg II absorption systems. These two categories can be reconciled if we assume an abundance gradient similar to local galaxies. Under that assumption we predict abundances 12 + log (O/H) = 7.1 and log (N/O) = -1.9 for the sub-DLA cloud, which is similar to high redshift DLA and sub-DLA systems. We find evidence for a rotational velocity of similar to200 km s(-1) over a length of similar to7 kpc. From the geometry and kinematics of the galaxy we estimate that the absorbing cloud does not belong to a rotating disk, but could originate in a rotating halo Y1 - 2005 ER - TY - JOUR A1 - Chambodut, Aude A1 - Mandea, Mioara T1 - Evidence for geomagnetic jerks in comprehensive models N2 - The rate of secular variation occasionally undergoes a sudden, sharp change, called a geomagnetic jerk. Such jerks have been detected in geomagnetic time series, centered-over the last four decades-around 1971, 1980, 1991, and 1999; others have been inferred from historical records. The geomagnetic jerks represent a reorganization of the secular variation, implying an internal origin, as established through spherical harmonic and wavelet analysis. However, some characteristics of jerks are not well understood. Here we estimate the occurrence dates for geomagnetic jerks, as they can be detected from a global geomagnetic model. This choice makes the present study novel, for two reasons. First, utilizing the comprehensive modelling approach allows for the use of a secular variation signal free of time-varying external fields and their corresponding induced counterpart, and observatory biases. Second, the model utilizes satellite data when available, in addition to observatory data. Indeed, POGO (1967 to 1971), MAGSAT (1979 to 1980), Orsted (1999 to present time) and CHAMP (2000 to present time) satellite measurements help to separate the different magnetic sources. In this study the CM4 comprehensive model is used for a global search of geomagnetic jerks and their occurrence dates. Our first result indicates that found geomagnetic jerks might not have been worldwide in occurrence. Moreover, the obtained dates suggest that jerks detected in the CM4 model over the last four decades occurred not simultaneously but at slightly different times around 1971, 1980 and 1991 Y1 - 2005 SN - 1343-8832 ER -