TY - BOOK A1 - Rabe, Thorid T1 - Physikdidaktische Lehrerprofessionalisierung zwischen Anspruch und Wirklichkeit : Antrittsvorlesung 2011-06-08 N2 - Physiklehrer bestimmen durch die Gestaltung des Unterrichts und damit durch ihr professionelles Handeln maßgeblich mit, wie die individuellen Lernprozesse der Schüler zu Inhalten der Physik ablaufen. Für die Entwicklung ihrer professionellen Handlungskompetenz müssen zukünftige Physiklehrer einerseits physikalisches, physikdidaktisches und pädagogisches Wissen erwerben und andererseits motiviert sein, dieses Wissen auch anzuwenden. In ihrer Vorlesung geht Thorid Rabe der Frage nach, welche physikdidaktischen Kompetenzen Studierende im Rahmen der universitären Ausbildung erwerben sollten. Am Beispiel der Lehrveranstaltung "Physikalische Schulexperimente" zeigt sie, wie physikdidaktische Theorie und praktisches Lehrerhandeln aufeinander bezogen werden können. Zudem wird sie ein Forschungsprojekt vorstellen, das einem bisher vernachlässigten Aspekt professioneller Handlungskompetenz nachgeht, nämlich den domänenspezifischen Selbstwirksamkeitserwartungen - dem Zutrauen in sich selbst, als Physiklehrer angemessen und erfolgreich handeln zu können. Y1 - 2011 UR - http://info.ub.uni-potsdam.de/multimedia/show_multimediafile.php?mediafile_id=548 PB - Univ.-Bibl. CY - Potsdam ER - TY - JOUR A1 - Qiu, Xunlin A1 - Wirges, Werner A1 - Gerhard, Reimund T1 - Beneficial and detrimental fatigue effects of dielectric barrier discharges on the piezoelectricity of polypropylene ferroelectrets JF - Journal of applied physics N2 - Cellular polypropylene (PP) ferroelectrets combine a large piezoelectricity with mechanical flexibility and elastic compliance. Their charging process represents a series of dielectric barrier discharges (DBDs) that generate a cold plasma with numerous active species and thus modify the inner polymer surfaces of the foam cells. Both the threshold for the onset of DBDs and the piezoelectricity of ferroelectrets are sensitive to repeated DBDs in the voids. It is found that the threshold voltage is approximately halved and the charging efficiency is clearly improved after only 10(3) DBD cycles. However, plasma modification of the inner surfaces from repeated DBDs deteriorates the chargeability of the voids, leading to a significant reduction of the piezoelectricity in ferroelectrets. After a significant waiting period, the chargeability of previously fatigued voids shows a partial recovery. The plasma modification is, however, detrimental to the stability of the deposited charges and thus also of the macroscopic dipoles and of the piezoelectricity. Fatigue from only 10(3) DBD cycles already results in significantly less stable piezoelectricity in cellular PP ferroelectrets. The fatigue rate as a function of the number of voltage cycles follows a stretched exponential. Fatigue from repeated DBDs can be avoided if most of the gas molecules inside the voids are removed via a suitable evacuation process. Y1 - 2011 U6 - https://doi.org/10.1063/1.3610507 SN - 0021-8979 SN - 1089-7550 VL - 110 IS - 2 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Qiu, Xunlin A1 - Gerhard, Reimund A1 - Mellinger, Axel T1 - Turning polymer foams or polymer-film systems into ferroelectrets dielectric barrier discharges in voids JF - IEEE transactions on dielectrics and electrical insulation N2 - Polymer foams and void-containing polymer-film systems with internally charged voids combine large piezoelectricity with mechanical flexibility and elastic compliance. This new class of soft materials (often called ferro-or piezoelectrets) has attracted considerable attention from science and industry. It has been found that the voids can be internally charged by means of dielectric barrier discharges (DBDs) under high electric fields. The charged voids can be considered as man-made macroscopic dipoles. Depending on the ferroelectret structure and the pressure of the internal gas, the voids may be highly compressible. Consequently, very large dipole-moment changes can be induced by mechanical or electrical stresses, leading to large piezoelectricity. DBD charging of the voids is a critical process for rendering polymer foams piezoelectric. Thus a comprehensive exploration of DBD charging is essential for the understanding and the optimization of piezoelectricity in ferroelectrets. Recent studies show that DBDs in the voids are triggered when the internal electric field reaches a threshold value according to Townsend's model of Paschen breakdown. During the DBDs, charges of opposite polarity are generated and trapped at the top and bottom internal surfaces of the gas-filled voids, respectively. The deposited charges induce an electric field opposite to the externally applied one and thus extinguish the DBDs. Back discharges may eventually be triggered when the external voltage is reduced or turned off. In order to optimize the efficiency of DBD charging, the geometry (in particular the height) of the voids, the type of gas and its pressure inside the voids are essential factors to be considered and to be optimized. In addition, the influence of the plasma treatment on the internal void surfaces during the DBDs should be taken into consideration. KW - Ferroelectret KW - piezoelectret KW - dielectric barrier discharge (DBD) KW - effective polarization KW - man-made dipole Y1 - 2011 U6 - https://doi.org/10.1109/TDEI.2011.5704490 SN - 1070-9878 VL - 18 IS - 1 SP - 34 EP - 42 PB - Inst. of Electr. and Electronics Engineers CY - Piscataway ER - TY - GEN A1 - Qiu, Xunlin T1 - Patterned piezo-, pyro-, and ferroelectricity of poled polymer electrets T2 - Journal of applied physics Y1 - 2011 U6 - https://doi.org/10.1063/1.3638069 SN - 0021-8979 VL - 110 IS - 5 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Prosen, Tomaz A1 - Ilievski, Enej T1 - Nonequilibrium phase transition in a periodically driven XY spin chain JF - Physical review letters N2 - We present a general formulation of Floquet states of periodically time-dependent open Markovian quasifree fermionic many-body systems in terms of a discrete Lyapunov equation. Illustrating the technique, we analyze periodically kicked XY spin-1/2 chain which is coupled to a pair of Lindblad reservoirs at its ends. A complex phase diagram is reported with reentrant phases of long range and exponentially decaying spin-spin correlations as some of the system's parameters are varied. The structure of phase diagram is reproduced in terms of counting nontrivial stationary points of Floquet quasiparticle dispersion relation. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevLett.107.060403 SN - 0031-9007 VL - 107 IS - 6 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Prosen, Tomaz T1 - Complexity and nonseparability of classical Liouvillian dynamics JF - Physical review : E, Statistical, nonlinear and soft matter physics N2 - We propose a simple complexity indicator of classical Liouvillian dynamics, namely the separability entropy, which determines the logarithm of an effective number of terms in a Schmidt decomposition of phase space density with respect to an arbitrary fixed product basis. We show that linear growth of separability entropy provides a stricter criterion of complexity than Kolmogorov-Sinai entropy, namely it requires that the dynamics be exponentially unstable, nonlinear, and non-Markovian. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevE.83.031124 SN - 1539-3755 VL - 83 IS - 3 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Postberg, Frank A1 - Schmidt, J. A1 - Hillier, J. A1 - Kempf, Sascha A1 - Srama, Ralf T1 - A salt-water reservoir as the source of a compositionally stratified plume on Enceladus JF - Nature : the international weekly journal of science N2 - The discovery of a plume of water vapour and ice particles emerging from warm fractures ('tiger stripes') in Saturn's small, icy moon Enceladus(1-6) raised the question of whether the plume emerges from a subsurface liquid source(6-8) or from the decomposition of ice(9-12). Previous compositional analyses of particles injected by the plume into Saturn's diffuse E ring have already indicated the presence of liquid water(8), but the mechanisms driving the plume emission are still debated(13). Here we report an analysis of the composition of freshly ejected particles close to the sources. Salt-rich ice particles are found to dominate the total mass flux of ejected solids (more than 99 per cent) but they are depleted in the population escaping into Saturn's E ring. Ice grains containing organic compounds are found to be more abundant in dense parts of the plume. Whereas previous Cassini observations were compatible with a variety of plume formation mechanisms, these data eliminate or severely constrain non-liquid models and strongly imply that a salt-water reservoir with a large evaporating surface(7,8) provides nearly all of the matter in the plume. Y1 - 2011 U6 - https://doi.org/10.1038/nature10175 SN - 0028-0836 VL - 474 IS - 7353 SP - 620 EP - 622 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Pontius, N. A1 - Kachel, T. A1 - Schüssler-Langeheine, C. A1 - Schlotter, W. F. A1 - Beye, Martin A1 - Sorgenfrei, Nomi A1 - Chang, C. F. A1 - Föhlisch, Alexander A1 - Wurth, W. A1 - Metcalf, P. A1 - Leonov, I. A1 - Yaresko, A. A1 - Stojanovic, N. A1 - Berglund, Martin A1 - Guerassimova, N. A1 - Duesterer, S. A1 - Redlin, H. A1 - Duerr, H. A. T1 - Time-resolved resonant soft x-ray diffraction with free-electron lasers femtosecond dynamics across the Verwey transition in magnetite JF - Applied physics letters N2 - Resonant soft x-ray diffraction (RSXD) with femtosecond (fs) time resolution is a powerful tool for disentangling the interplay between different degrees of freedom in strongly correlated electron materials. It allows addressing the coupling of particular degrees of freedom upon an external selective perturbation, e. g., by an optical or infrared laser pulse. Here, we report a time-resolved RSXD experiment from the prototypical correlated electron material magnetite using soft x-ray pulses from the free-electron laser FLASH in Hamburg. We observe ultrafast melting of the charge-orbital order leading to the formation of a transient phase, which has not been observed in equilibrium. Y1 - 2011 U6 - https://doi.org/10.1063/1.3584855 SN - 0003-6951 VL - 98 IS - 18 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Pohl, Martin A1 - Eichler, David T1 - Origin of ultra-high-energy galactic cosmic rays the isotropy problem JF - The astrophysical journal : an international review of spectroscopy and astronomical physics N2 - We study the propagation of ultra-high-energy cosmic rays (UHECRs) in the Galaxy, concentrating on the energy range below the ankle in the spectrum at 4 EeV. A Monte Carlo method, based on analytical solutions to the time-dependent diffusion problem, is used to account for intermittency by placing sources at random locations. Assuming a source population that scales with baryon mass density or star formation (e.g., long GRB), we derive constraints arising from intermittency and the observational limits on the composition and anisotropy. It is shown that the composition and anisotropy at 10(18) eV are difficult to reproduce and require that either (1) the particle mean free path is much smaller than a gyroradius, implying the escape time is very long, (2) the composition is heavier than suggested by recent Auger data, (3) the ultra-high-energy sub-ankle component is mostly extragalactic, or (4) we are living in a rare lull in the UHECR production, and the current UHECR intensity is far below the Galactic time average. We therefore recommend a strong observational focus on determining the UHECR composition around 10(18) eV. KW - cosmic rays KW - gamma-ray burst: general Y1 - 2011 U6 - https://doi.org/10.1088/0004-637X/742/2/114 SN - 0004-637X VL - 742 IS - 2 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Pikovskij, Arkadij A1 - Rosenblum, Michael T1 - Dynamics of heterogeneous oscillator ensembles in terms of collective variables JF - Physica :D, Nonlinear phenomena N2 - We consider general heterogeneous ensembles of phase oscillators, sine coupled to arbitrary external fields. Starting with the infinitely large ensembles, we extend the Watanabe-Strogatz theory, valid for identical oscillators, to cover the case of an arbitrary parameter distribution. The obtained equations yield the description of the ensemble dynamics in terms of collective variables and constants of motion. As a particular case of the general setup we consider hierarchically organized ensembles, consisting of a finite number of subpopulations, whereas the number of elements in a subpopulation can be both finite or infinite. Next, we link the Watanabe-Strogatz and Ott-Antonsen theories and demonstrate that the latter one corresponds to a particular choice of constants of motion. The approach is applied to the standard Kuramoto-Sakaguchi model, to its extension for the case of nonlinear coupling, and to the description of two interacting subpopulations, exhibiting a chimera state. With these examples we illustrate that, although the asymptotic dynamics can be found within the framework of the Ott-Antonsen theory, the transients depend on the constants of motion. The most dramatic effect is the dependence of the basins of attraction of different synchronous regimes on the initial configuration of phases. KW - Coupled oscillators KW - Oscillator ensembles KW - Kuramoto model KW - Nonlinear coupling KW - Watanabe-Strogatz theory KW - Ott-Antonsen theory Y1 - 2011 U6 - https://doi.org/10.1016/j.physd.2011.01.002 SN - 0167-2789 VL - 240 IS - 9-10 SP - 872 EP - 881 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Pikovskij, Arkadij A1 - Fishman, Shmuel T1 - Scaling properties of weak chaos in nonlinear disordered lattices JF - Physical review : E, Statistical, nonlinear and soft matter physics N2 - We study the discrete nonlinear Schrodinger equation with a random potential in one dimension. It is characterized by the length, the strength of the random potential, and the field density that determines the effect of nonlinearity. Following the time evolution of the field and calculating the largest Lyapunov exponent, the probability of the system to be regular is established numerically and found to be a scaling function of the parameters. This property is used to calculate the asymptotic properties of the system in regimes beyond our computational power. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevE.83.025201 SN - 1539-3755 SN - 1550-2376 VL - 83 IS - 2 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Pietzsch, Annette A1 - Sun, Y. -P. A1 - Hennies, Franz A1 - Rinkevicius, Z. A1 - Karlsson, Hans O. A1 - Schmitt, Thorsten A1 - Strocov, Vladimir N. A1 - Andersson, Joakim A1 - Kennedy, B. A1 - Schlappa, J. A1 - Föhlisch, Alexander A1 - Rubensson, Jan-Erik A1 - Gel'mukhanov, F. T1 - Spatial quantum beats in vibrational resonant inelastic soft X-ray scattering at dissociating states in oxygen JF - Physical review letters N2 - Resonant inelastic soft x-ray scattering (RIXS) spectra excited at the 1 sigma(g) -> 3 sigma(u) resonance in gas-phase O-2 show excitations due to the nuclear degrees of freedom with up to 35 well-resolved discrete vibronic states and a continuum due to the kinetic energy distribution of the separated atoms. The RIXS profile demonstrates spatial quantum beats caused by two interfering wave packets with different momenta as the atoms separate. Thomson scattering strongly affects both the spectral profile and the scattering anisotropy. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevLett.106.153004 SN - 0031-9007 VL - 106 IS - 15 PB - American Physical Society CY - College Park ER - TY - THES A1 - Partl, Adrian M. T1 - Cosmological radiative transfer and the lonisation of the integalactic medium Y1 - 2011 CY - Potsdam ER - TY - THES A1 - Osterloh, Lukas T1 - Retrieving aerosol microphysical properties from multiwavelength Lidar Data Y1 - 2011 CY - Potsdam ER - TY - JOUR A1 - Oskinova, Lida A1 - Todt, Helge Tobias A1 - Ignace, Richard A1 - Brown, John C. A1 - Cassinelli, Joseph P. A1 - Hamann, Wolf-Rainer T1 - Early magnetic B-type stars X-ray emission and wind properties JF - Monthly notices of the Royal Astronomical Society N2 - We present a comprehensive study of X-ray emission by, and wind properties of, massive magnetic early B-type stars. Dedicated XMM-Newton observations were obtained for three early-type B-type stars, xi(1) CMa, V2052 Oph and zeta Cas, with recently discovered magnetic fields. We report the first detection of X-ray emission from V2052 Oph and zeta Cas. The latter is one the softest X-ray sources among the early-type stars, while the former is one of the X-ray faintest. The observations show that the X-ray spectra of our programme stars are quite soft with the bulk of X-ray emitting material having a temperature of about 1 MK. We compile the complete sample of early B-type stars with detected magnetic fields to date and existing X-ray measurements, in order to study whether the X-ray emission can be used as a general proxy for stellar magnetism. We find that the X-ray properties of early massive B-type magnetic stars are diverse, and that hard and strong X-ray emission does not necessarily correlate with the presence of a magnetic field, corroborating similar conclusions reached earlier for the classical chemically peculiar magnetic Bp-Ap stars. We analyse the ultraviolet (UV) spectra of five non-supergiant B stars with magnetic fields (tau Sco, beta Cep, xi(1) CMa, V2052 Oph and zeta Cas) by means of non-local thermodynamic equilibrium (non-LTE) iron-blanketed model atmospheres. The latter are calculated with the Potsdam Wolf-Rayet (PoWR) code, which treats the photosphere as well as the wind, and also accounts for X-rays. With the exception of t Sco, this is the first analysis of these stars by means of stellar wind models. Our models accurately fit the stellar photospheric spectra in the optical and the UV. The parameters of X-ray emission, temperature and flux are included in the model in accordance with observations. We confirm the earlier findings that the filling factors of X-ray emitting material are very high. Our analysis reveals that the magnetic early-type B stars studied here have weak winds with velocities not significantly exceeding upsilon(esc). The mass-loss rates inferred from the analysis of UV lines are significantly lower than predicted by hydrodynamically consistent models. We find that, although the X-rays strongly affect the ionization structure of the wind, this effect is not sufficient in reducing the total radiative acceleration. When the X-rays are accounted for at the intensity and temperatures observed, there is still sufficient radiative acceleration to drive a stronger mass-loss than we empirically infer from the UV spectral lines. KW - techniques: spectroscopic KW - stars: magnetic field KW - stars: massive KW - stars: mass loss KW - X-rays: stars Y1 - 2011 U6 - https://doi.org/10.1111/j.1365-2966.2011.19143.x SN - 0035-8711 VL - 416 IS - 2 SP - 1456 EP - 1474 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Oskinova, Lida A1 - Hamann, Wolf-Rainer A1 - Cassinelli, Joseph P. A1 - Brown, John C. A1 - Todt, Helge Tobias T1 - X-ray emission from massive stars with magnetic fields JF - Astronomische Nachrichten = Astronomical notes N2 - We investigate the connections between the magnetic fields and the X-ray emission from massive stars. Our study shows that the X-ray properties of known strongly magnetic stars are diverse: while some comply to the predictions of the magnetically confined wind model, others do not. We conclude that strong, hard, and variable X-ray emission may be a sufficient attribute of magnetic massive stars, but it is not a necessary one. We address the general properties of X-ray emission from "normal" massive stars, especially the long standing mystery about the correlations between the parameters of X-ray emission and fundamental stellar properties. The recent development in stellar structure modeling shows that small-scale surface magnetic fields may be common. We suggest a "hybrid" scenario which could explain the X-ray emission from massive stars by a combination of magnetic mechanisms on the surface and shocks in the stellar wind. The magnetic mechanisms and the wind shocks are triggered by convective motions in sub-photospheric layers. This scenario opens the door for a natural explanation of the well established correlation between bolometric and X-ray luminosities. KW - stars: magnetic fields KW - stars: mass-loss KW - stars: winds, outflows KW - stars: Wolf-Rayet KW - techniques: spectroscopic KW - X-rays: stars Y1 - 2011 U6 - https://doi.org/10.1002/asna.201111602 SN - 0004-6337 VL - 332 IS - 9-10 SP - 988 EP - 993 PB - Wiley-Blackwell CY - Malden ER - TY - JOUR A1 - Navirian, Hengameh A. A1 - Herzog, Marc A1 - Goldshteyn, J. A1 - Leitenberger, Wolfram A1 - Vrejoiu, Ionella A1 - Khakhulin, D. A1 - Wulff, M. A1 - Shayduk, Roman A1 - Gaal, P. A1 - Bargheer, Matias T1 - Shortening x-ray pulses for pump-probe experiments at synchrotrons JF - Journal of applied physics N2 - We implemented an experimental scheme for ultrafast x-ray diffraction at storage rings based on a laser-driven Bragg-switch that shortens the x-ray pulses emitted from an undulator. The increased time-resolution is demonstrated by observing changes of intensity, position and width of the diffraction peaks of a La(0.7)Sr(0.3)MnO(3)/SrTiO(3) superlattice sample after optical excitation, i.e., by quantitatively measuring the propagation of an expansion wave through the sample. These experimental transients with timescales of 35 to 60 ps evidence a reduction of the x-ray pulse duration by a factor of two. Y1 - 2011 U6 - https://doi.org/10.1063/1.3601057 SN - 0021-8979 VL - 109 IS - 12 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Müller, Matthias M. A1 - Haakh, Harald R. A1 - Calarco, Tommaso A1 - Koch, Christiane P. A1 - Henkel, Carsten T1 - Prospects for fast Rydberg gates on an atom chip JF - Quantum information processing N2 - Atom chips are a promising candidate for a scalable architecture for quantum information processing provided a universal set of gates can be implemented with high fidelity. The difficult part in achieving universality is the entangling two-qubit gate. We consider a Rydberg phase gate for two atoms trapped on a chip and employ optimal control theory to find the shortest gate that still yields a reasonable gate error. Our parameters correspond to a situation where the Rydberg blockade regime is not yet reached. We discuss the role of spontaneous emission and the effect of noise from the chip surface on the atoms in the Rydberg state. KW - Optimal control KW - Phase gate KW - Rydberg atoms KW - Cavity quantum electrodynamics Y1 - 2011 U6 - https://doi.org/10.1007/s11128-011-0296-0 SN - 1570-0755 VL - 10 IS - 6 SP - 771 EP - 792 PB - Springer CY - New York ER - TY - JOUR A1 - Müller, Markus P. A1 - Gross, David A1 - Eisert, Jens T1 - Concentration of Measure for Quantum States with a Fixed Expectation Value JF - Communications in mathematical physics N2 - Given some observable H on a finite-dimensional quantum system, we investigate the typical properties of random state vectors vertical bar psi >> that have a fixed expectation value < psi vertical bar H vertical bar psi > = E with respect to H. Under some conditions on the spectrum, we prove that this manifold of quantum states shows a concentration of measure phenomenon: any continuous function on this set is almost everywhere close to its mean. We also give a method to estimate the corresponding expectation values analytically, and we prove a formula for the typical reduced density matrix in the case that H is a sum of local observables. We discuss the implications of our results as new proof tools in quantum information theory and to study phenomena in quantum statistical mechanics. As a by-product, we derive a method to sample the resulting distribution numerically, which generalizes the well-known Gaussian method to draw random states from the sphere. Y1 - 2011 U6 - https://doi.org/10.1007/s00220-011-1205-1 SN - 0010-3616 VL - 303 IS - 3 SP - 785 EP - 824 PB - Springer CY - New York ER - TY - THES A1 - Mösta, Philipp T1 - Novel aspects of the dynamics of binary black-hole mergers T1 - Neue Aspekte der Dynamik von Kollisionen binärer schwarzer Löcher N2 - The inspiral and merger of two black holes is among the most exciting and extreme events in our universe. Being one of the loudest sources of gravitational waves, they provide a unique dynamical probe of strong-field general relativity and a fertile ground for the observation of fundamental physics. While the detection of gravitational waves alone will allow us to observe our universe through an entirely new window, combining the information obtained from both gravitational wave and electro-magnetic observations will allow us to gain even greater insight in some of the most exciting astrophysical phenomena. In addition, binary black-hole mergers serve as an intriguing tool to study the geometry of space-time itself. In this dissertation we study the merger process of binary black-holes in a variety of conditions. Our results show that asymmetries in the curvature distribution on the common apparent horizon are correlated to the linear momentum acquired by the merger remnant. We propose useful tools for the analysis of black holes in the dynamical and isolated horizon frameworks and shed light on how the final merger of apparent horizons proceeds after a common horizon has already formed. We connect mathematical theorems with data obtained from numerical simulations and provide a first glimpse on the behavior of these surfaces in situations not accessible to analytical tools. We study electro-magnetic counterparts of super-massive binary black-hole mergers with fully 3D general relativistic simulations of binary black-holes immersed both in a uniform magnetic field in vacuum and in a tenuous plasma. We find that while a direct detection of merger signatures with current electro-magnetic telescopes is unlikely, secondary emission, either by altering the accretion rate of the circumbinary disk or by synchrotron radiation from accelerated charges, may be detectable. We propose a novel approach to measure the electro-magnetic radiation in these simulations and find a non-collimated emission that dominates over the collimated one appearing in the form of dual jets associated with each of the black holes. Finally, we provide an optimized gravitational wave detection pipeline using phenomenological waveforms for signals from compact binary coalescence and show that by including spin effects in the waveform templates, the detection efficiency is drastically improved as well as the bias on recovered source parameters reduced. On the whole, this disseration provides evidence that a multi-messenger approach to binary black-hole merger observations provides an exciting prospect to understand these sources and, ultimately, our universe. N2 - Schwarze Löcher gehören zu den extremsten und faszinierensten Objekten in unserem Universum. Elektromagnetische Strahlung kann nicht aus ihrem Inneren entkommen, und sie bilden die kompaktesten Objekte, die wir kennen. Wir wissen heute, dass in den Zentren der meisten Galaxien sehr massereiche schwarze Löcher vorhanden sind. Im Fall unserer eigenen Galaxie, der Milchstrasse, ist dieses schwarze Loch ungefähr vier Millionen mal so schwer wie unsere Sonne. Wenn zwei Galaxien miteinander kollidieren, führt dies auch dazu, dass ihre beiden schwarzen Löcher kollidieren und zu einem einzelnen schwarzen Loch verschmelzen. Das Simulieren einer solchen Kollision von zwei schwarzen Löchern, die Vorhersage sowie Analyse der von ihnen abgestrahlten Energie in Form von Gravitations- und elektromagnetischen Wellen, bildet das Thema der vorliegenden Dissertation. Im ersten Teil dieser Arbeit untersuchen wir die Verschmelzung von zwei schwarzen Löchern unter verschiedenen Gesichtspunkten. Wir zeigen, dass Ungleichmässigkeiten in der Geometrie des aus einer Kollision entstehenden schwarzen Loches dazu führen, dass es zuerst beschleunigt und dann abgebremst wird, bis diese Ungleichmässigkeiten in Form von Gravitationswellen abgetrahlt sind. Weiterhin untersuchen wir, wie der genaue Verschmelzungsprozess aus einer geometrischen Sicht abläuft und schlagen neue Methoden zur Analyse der Raumzeitgeometrie in Systemen vor, die schwarze Löcher enthalten. Im zweiten Teil dieser Arbeit beschäftigen wir uns mit den Gravitationswellen und elektromagnetischer Strahlung, die bei einer Kollision von zwei schwarzen Löchern freigesetzt wird. Gravitationswellen sind Wellen, die Raum und Zeit dehnen und komprimieren. Durchläuft uns eine Gravitationswelle, werden wir in einer Richtung minimal gestreckt, während wir in einer anderen Richtung minimal zusammengedrückt werden. Diese Effekte sind allerdings so klein, dass wir sie weder spüren, noch auf einfache Weise messen können. Bei einer Kollision von zwei schwarzen Löchern wird eine grosse Menge Energie in Form von Gravitationswellen und elektromagnetischen Wellen abgestrahlt. Wir zeigen, dass beide Signale in ihrer Struktur sehr ähnlich sind, dass aber die abgestrahlte Energie in Gravitationswellen um ein Vielfaches grösser ist als in elektromagnetischer Strahlung. Wir führen eine neue Methode ein, um die elektromagnetische Strahlung in unseren Simulationen zu messen und zeigen, dass diese dazu führt, dass sich die räumliche Struktur der Strahlung verändert. Abschliessend folgern wir, dass in der Kombination der Signale aus Gravitationswellen und elektromagnetischer Strahlung eine grosse Chance liegt, ein System aus zwei schwarzen Löchern zu detektieren und in einem weiteren Schritt zu analysieren. Im dritten und letzen Teil dieser Dissertation entwickeln wir ein verbessertes Suchverfahren für Gravitationswellen, dass in modernen Laser-Interferometerexperimenten genutzt werden kann. Wir zeigen, wie dieses Verfahren die Chancen für die Detektion eines Gravitationswellensignals deutlich erhöht, und auch, dass im Falle einer erfolgreichen Detektion eines solchen Signals, seine Parameter besser bestimmt werden können. Wir schliessen die Arbeit mit dem Fazit, dass die Kollision von zwei schwarzen Löchern ein hochinteressantes Phenomenon darstellt, das uns neue Möglichkeiten bietet die Gravitation sowie eine Vielzahl anderer fundamentaler Vorgänge in unserem Universum besser zu verstehen. KW - schwarze Löcher KW - elektromagnetische Strahlung KW - Allgemeine Relativitätstheorie KW - Gravitationswellen KW - Raumzeitgeometrie KW - black-holes KW - gravitational waves KW - electromagnetic counterparts KW - general relativity KW - space-time geometry Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-59820 ER -