@article{40549, author = {{Grotjahn, Rebecca}}, journal = {{Viva voce}}, pages = {{9--13}}, title = {{{Angelica Catalani – Das Bild der Diva}}}, volume = {{57/58}}, year = {{2001}}, } @inproceedings{40907, abstract = {{In reduced-rank signal processing for radar, sonar, and digital communications, we seek the right tradeoff between model bias and model variance for reconstructing signals from noisy data. Here, we extend the classical theory by considering the low-rank approximation of complex random vectors, which may or may not be proper. We show that, in general, widely linear approximation is superior to strictly linear approximation, unless the vector to be approximated is proper, in which case the optimum procedure is strictly linear. We analyze the case where the approximated random vector becomes proper in its internal coordinate system. This class of random vector, which we call generalized proper, possesses qualities similar to proper random vectors.}}, author = {{Schreier, Peter J. and Scharf, Louis L.}}, booktitle = {{Proc. 35th\ Asilomar Conf.\ Signals Syst.\ Computers}}, pages = {{597–601}}, title = {{{Low-rank approximation of improper complex random vectors}}}, doi = {{10.1109/ACSSC.2001.986993}}, volume = {{1}}, year = {{2001}}, } @article{34897, abstract = {{This paper announces the creation of a database for number fields. It describes the contents and the methods of access, indicates the origin of the polynomials, and formulates the aims of this collection of fields.}}, author = {{Klüners, Jürgen and Malle, Gunter}}, issn = {{1461-1570}}, journal = {{LMS Journal of Computation and Mathematics}}, keywords = {{Computational Theory and Mathematics, General Mathematics}}, pages = {{182--196}}, publisher = {{Wiley}}, title = {{{A Database for Field Extensions of the Rationals}}}, doi = {{10.1112/s1461157000000851}}, volume = {{4}}, year = {{2001}}, } @book{40153, author = {{Fuchs, Christian}}, publisher = {{Libri BOD}}, title = {{{Soziale Selbstorganisation im informationsgesellschaftlichen Kapitalismus (Social Self-Organization and Informational Capitalism)}}}, year = {{2001}}, } @article{26003, abstract = {{Long-chain n-alkylamine surfactants have been used as structure-directing agents in the synthesis of mesoporous aluminophosphates by a highly cooperative formation mechanism in an alcoholic system. Small amounts of water in the synthesis mixture play a significant role in the hydrolysis of the aluminum precursor (Al[OiPr]3) and are important for the quality of the mesostructured products. The materials exhibit disordered mesostructures, the stability and structural order of which can be improved by a postsynthetic thermal treatment. The products are then stable enough for the removal of the surfactant molecules by acidic solvent extraction, yielding surface areas up to 690 m2/g.}}, author = {{Tiemann, Michael and Schulz, Marcus and Jäger, Christian and Fröba, Michael}}, issn = {{0897-4756}}, journal = {{Chemistry of Materials}}, pages = {{2885--2891}}, title = {{{Mesoporous Aluminophosphate Molecular Sieves Synthesized under Nonaqueous Conditions}}}, doi = {{10.1021/cm011044p}}, year = {{2001}}, } @article{26002, abstract = {{Over the past few years a growing number of scientists have dedicated their attention to the synthesis of mesostructured aluminophosphates following the concept of supramolecular structure direction. Their research has produced a large variety of synthetic approaches and yielded materials with various structural properties. Today a substantial number of publications have accumulated; this short review provides a general summary of the literature with the aim to display the opportunities for future work.}}, author = {{Tiemann, Michael and Fröba, Michael}}, issn = {{0897-4756}}, journal = {{Chemistry of Materials}}, pages = {{3211--3217}}, title = {{{Mesostructured Aluminophosphates Synthesized with Supramolecular Structure Directors}}}, doi = {{10.1021/cm0110371}}, year = {{2001}}, } @inbook{43303, abstract = {{This chapter focuses on the carrier interaction effects—that is, the many-body Coulomb correlations and their influence on band-gap semiconductor optical nonlinearities. The near band-gap semiconductor response is determined by the optical interaction with the resonant or near resonant material polarization that may result in the excitation of carriers (electron–hole pairs) and/or transient coherent nonlinearities. The microscopic analysis of these effects requires the investigation of the relevant quasi-particles and their interactions. Whereas the basic occurrence of a blue shift can be motivated already based on a simple two-level model, a more detailed understanding of the optical Stark effect in semiconductors requires a microscopic modeling of the relevant bands as well as the inclusion of the many-body Coulomb interaction. Compensations among the first- and higher-order Coulomb terms at the spectral positions of the exciton are obtained in the differential absorption induced by incoherent occupations.}}, author = {{Meier, Torsten and Koch, S.W.}}, booktitle = {{Ultrafast Physical Processes in Semiconductors}}, editor = {{Tsen, K.T.}}, isbn = {{978-0-12-752176-3}}, pages = {{231--313}}, publisher = {{Elsevier}}, title = {{{Coulomb correlation signatures in the excitonic optical nonlinearities of semiconductors}}}, doi = {{10.1016/S0080-8784(01)80172-1}}, volume = {{67}}, year = {{2001}}, } @article{43307, abstract = {{The influence of fifth-order coherences on the spectrally resolved four-wave mixing response of predominantly homogeneously broadened quasi-two-dimensional excitons is studied. Fifth-order signatures are discussed as a function of spectral position and excitation polarization. An exciton–biexciton beating for positive delay times is the dominant effect, which is pronounced at the exciton–biexciton transition for collinearly polarized excitation and at the exciton transition for cross-linearly polarized excitation. For negative delay times and collinearly polarized excitation a pronounced exciton–biexciton beating at the exciton resonance is observed that is vanishing for long negative delays owing to the faster dephasing in the two-exciton continuum compared with the bound biexciton state. These results are in qualitative agreement with microscopic model calculations that include the coherent dynamics of one- and two-exciton resonances up to the fifth order in the optical field.}}, author = {{Meier, Torsten and Langbein, W. and Koch, S.W. and Hvam, J.M.}}, journal = {{Journal of the Optical Society of America B}}, number = {{9}}, pages = {{1318--1325}}, publisher = {{Optical Society of America}}, title = {{{Spectral signatures of χ(5) processes in four-wave mixing of homogeneously broadened excitons}}}, doi = {{10.1364/JOSAB.18.001318}}, volume = {{18}}, year = {{2001}}, } @article{43306, abstract = {{Linear and nonlinear optical absorption spectra are studied theoretically for semiconductor nanorings penetrated by a magnetic field. Due to the Aharanov-Bohm effect the spectral position as well as the oscillator strength of the exciton change periodically as function of the magnetic flux enclosed by the ring. In the nonlinear differential absorption spectra it is found that the magnetic field strongly modifies Coulomb many-body correlations. In particular, the magnetic-field-induced increase of the exciton binding energy is accompanied by a decrease of the biexciton binding energy. The persistence of these effects in the presence of energetic disorder is analyzed.}}, author = {{Meier, Torsten and Thomas, P. and Koch, S.W.}}, journal = {{The European Physical Journal B - Condensed Matter and Complex Systems}}, pages = {{249--256}}, publisher = {{EDP sciences}}, title = {{{Linear and nonlinear optical properties of semiconductor nanorings with magnetic field and disorder-Influence on excitons and biexcitons}}}, doi = {{10.1007/s100510170133}}, volume = {{22}}, year = {{2001}}, } @inbook{43302, abstract = {{In this chapter a microscopic many-body theory is reviewed that allows one to compute the linear and nonlinear optical properties of semiconductor superlattices in the presence of homogeneous electric fields applied in the growth direction. The theory includes the process of optical excitation, the Coulomb interaction among the carriers, carrier-phonon coupling, and the acceleration induced by the electric field. Coherent phenomena induced by dc and ac fields, like Bloch oscillations and dynamical localization, are introduced and discussed. The theoretical analysis concentrates on the signatures and observability of such phenomena in linear and nonlinear optical experiments.}}, author = {{Meier, Torsten and Thomas, P. and Koch, S.W.}}, booktitle = {{Ultrafast Phenomena in Semiconductors}}, editor = {{Tsen, K.T.}}, isbn = {{978-1-4612-6562-7}}, pages = {{1--92}}, publisher = {{Springer}}, title = {{{Coherent Dynamics of Photoexcited Semiconductor Superlattices with Applied Homogeneous Electric Fields}}}, doi = {{10.1007/978-1-4613-0203-2_1}}, year = {{2001}}, } @article{43305, abstract = {{Pump-probe experiments on high-quality InxGa1−x As quantum wells are used to investigate the influence of light-hole excitons on the optical Stark effect. For anticircular polarization of pump and probe pulses and a moderate negative detuning of the pump energy, a redshift of the heavy-hole resonance is observed. However, with increasingly negative detuning a transition from this redshift to a blueshift is found. Microscopic calculations that include both heavy holes and light holes reproduce the experimental results. The theoretical analysis shows that the observation of the redshift depends very sensitively on the detuning of the pump pulses and the heavy-hole to light-hole splitting.}}, author = {{Meier, Torsten and Brick, P. and Ell, C. and Khitrova, G. and Gibbs, H.M. and Sieh, C. and Koch, S.W.}}, journal = {{Physical Review B}}, number = {{7}}, publisher = {{American Physical Society}}, title = {{{Influence of Light Holes on the Heavy-Hole Excitonic Optical Stark Effect}}}, doi = {{10.1103/PhysRevB.64.075323}}, volume = {{64}}, year = {{2001}}, } @article{43304, abstract = {{The coherent dynamics of magnetoexcitons in semiconductor nanorings following pulsed optical excitation is studied. The calculated temporal evolution of the excitonic dipole moment may be understood as a superposition of the relative motion of electrons and holes and a global circular motion associated with the magnetic-field splitting of these states. This dynamics of the electron-hole pairs can be generated either by local optical excitation of an ordered ring or, alternatively, by homogeneous excitation of rings with broken rotational symmetry due to disorder or band tilting.}}, author = {{Meier, Torsten and Maschke, K. and Thomas, P. and Koch, S.W.}}, journal = {{The European Physical Journal B - Condensed Matter and Complex Systems}}, pages = {{599--606}}, publisher = {{EDP Sciences, Springer-Verlag}}, title = {{{Coherent Dynamics of Magnetoexcitons in Semiconductor Nanorings}}}, doi = {{10.1007/s100510170305}}, volume = {{19}}, year = {{2001}}, } @book{43563, editor = {{Fermor, Gotthard and Ruddat, Günter and Schroeter-Wittke, Harald}}, isbn = {{ ‎ 9783870620462}}, pages = {{380}}, publisher = {{CMZ-Verlag}}, title = {{{Gemeindekulturpädagogik. Henning Schröer zum 70. Geburtstag}}}, year = {{2001}}, } @inbook{43574, author = {{Schroeter-Wittke, Harald}}, booktitle = {{Evangelischer Taschenkatechismus}}, editor = {{Clasen, Winrich C.-W. and Meyer-Blanck, Michael and Ruddat, Günter}}, pages = {{48--50}}, title = {{{Kirchentag}}}, year = {{2001}}, } @misc{43577, author = {{Schroeter-Wittke, Harald}}, booktitle = {{Theologische Realenzyklopädie}}, pages = {{168--172}}, title = {{{Thadden-Trieglaff, Reinold von (1891-1976)}}}, volume = {{33}}, year = {{2001}}, } @article{43572, author = {{Schroeter-Wittke, Harald}}, journal = {{Forum Kirchenmusik}}, number = {{5}}, pages = {{13--16}}, title = {{{Die Orgel und die Kasualien}}}, volume = {{52}}, year = {{2001}}, } @misc{43576, author = {{Schroeter-Wittke, Harald}}, booktitle = {{Religion in Geschichte und Gegenwart }}, pages = {{1303--1306}}, title = {{{Kirchentag}}}, volume = {{IV}}, year = {{2001}}, } @misc{43588, author = {{Schroeter-Wittke, Harald and Wicke, Berthold}}, title = {{{Liturgisches Konzert. Vierhändige Klaviermusik zwischen öffentlicher Religion und privater Andacht (CD mit Werken von Johannes Brahms: Variationen über ein Thema von Schumann op. 23 (1861); Claude Debussy: Six épigraphes antiques (1914) und Paul Hindemith: Symphonie "Mathis der Maler" (1934)}}}, year = {{2001}}, } @inbook{43587, author = {{Schroeter-Wittke, Harald}}, booktitle = {{Kirchentags-Programmheft Frankfurt 2001}}, pages = {{137--138}}, title = {{{PaxAN! Das "andere" Börsenspiel zum Kirchentag 2001}}}, year = {{2001}}, } @inproceedings{43614, abstract = {{The dynamics of optically generated electron-hole pairs is investigated in a disordered semiconductor nanowire. The particle pairs are generated by short laser pulses and their dynamics is followed using the Heisenberg equation of motion. Is is shown that Coulomb-correlation acts against localization in the case of the two-interacting particles (TIP) problem. Furthermore, currents are generated using a coherent combination of full-gap and half-gap pulses. The subsequent application of a full-gap pulse after time τ produces an intraband echo phenomenon 2τ time later. The echo current is shown to depend on the mass ratio between the electrons and the holes.}}, author = {{Meier, Torsten and Varga, I. and Schlichenmaier, C. and Maschke, K. and Thomas, P. and Koch, S.W.}}, booktitle = {{Proceedings of the XXXVIth Rencontres de Moriond on Electronic Correlations: From Meso-Physics to Nano-Physics}}, editor = {{Martin, Thierry and Tran Thanh Van, J. and Montambaux, Gilles}}, location = {{Les Arcs, France}}, pages = {{343--347}}, publisher = {{EDP Sciences}}, title = {{{Dynamics of Coulomb-correlated electron-hole pairs in disordered semiconductor nanowires}}}, doi = {{10.48550/arXiv.cond-mat/0111452}}, year = {{2001}}, }