Refine
Year of publication
- 2011 (26) (remove)
Document Type
- Doctoral Thesis (26) (remove)
Is part of the Bibliography
- yes (26) (remove)
Keywords
- Quasare (2)
- AGN (1)
- Aerosole (1)
- Aerosols (1)
- Aktomyosin (1)
- Allgemeine Relativitätstheorie (1)
- Arctic (1)
- Arktis (1)
- Astrophysik (1)
- Azobenzen (1)
- Bose-Einstein condensation (1)
- Bose-Einstein-Kondensation (1)
- Casimir-Polder interaction (1)
- Casimir-Polder-Interaktion (1)
- Chemical Abundances (1)
- DFB laser (1)
- DFB-Laser (1)
- Datenanalyse (1)
- Dictyostelium (1)
- Dielektrische Spektroskopie (1)
- Einstein's field equations (1)
- Einsteins Feldgleichungen (1)
- Extremereignisse (1)
- Feld-Effekt-Transistoren (1)
- Fernerkundung (1)
- Ferroelectrets (1)
- Ferroelectrics (1)
- Ferroelektrete (1)
- Ferroelektrik (1)
- Flüssigkristalle (1)
- Galaxie (1)
- Galaxien (1)
- Galaxies (1)
- Galaxy (1)
- Gravitationswellen (1)
- Greenland (1)
- Grönland (1)
- Hohlraum-Quantenelektrodynamik (1)
- Holografie (1)
- Hysterese (1)
- Indian summer monsoon (1)
- Indischer Sommer-Monsun (1)
- Inlandeis (1)
- Integral field spectroscopy (1)
- Integralfeld-Spectroskopie (1)
- Interstellar medium (1)
- Interstellares Medium (1)
- Kaskade (1)
- Klimawandel (1)
- Komplexe Systeme (1)
- Lidar (1)
- Markov-Prozesse (1)
- Mathematikdidaktik (1)
- Metall-Isolator-Halbleiter (1)
- Milchstraße (1)
- Milky Way (1)
- Nanokomposite (1)
- Nichtlinear angeregte Fluoreszenz (1)
- Nichtlineare Dynamik (1)
- Oberflächengitter (1)
- PBP10 (1)
- PDLC (1)
- Paleoclimatology (1)
- Paläoklimatologie (1)
- Physik (1)
- Physikdidaktik (1)
- Polarisationsverteilung (1)
- Polarization distribution (1)
- Quasars (1)
- Raumzeitgeometrie (1)
- Remote Sensing (1)
- Schwarze Löcher (1)
- Spectroscopy (1)
- Spektroskopie (1)
- Stabilität (1)
- Statistik (1)
- Synchronisation (1)
- Tensor-Zerlegungen (1)
- Thermal-Pulse Tomography (1)
- Transiente Absorption (1)
- Vakuumschwankungen (1)
- Vorstellungen (1)
- Wellenlängenverschiebung (1)
- Wiskostatin (1)
- Wissenschaftstheorie (1)
- Wärmepuls-Tomographie (1)
- Zustandsmodell (1)
- Zwangsgleichungen (1)
- actomyosin (1)
- astrophysics (1)
- azobenzene (1)
- black holes (1)
- black-holes (1)
- cGMP (1)
- cascade (1)
- cavity quantum electrodynamics (1)
- chemische Häufigkeiten (1)
- climate change (1)
- complex networks (1)
- complex systems (1)
- conceptions (1)
- constraint equations (1)
- critical collapse (1)
- data analysis (1)
- dielectric elastomers (1)
- dielectric spectroskopie (1)
- dielektrische Elastomere (1)
- electromagnetic counterparts (1)
- electromechanical response (1)
- electrostatic energy density (1)
- elektromagnetische Strahlung (1)
- elektromechanische Reaktion (1)
- elektrostatische Energiedichte (1)
- elliptic systems (1)
- elliptisches Gleichungssystem (1)
- extreme events (1)
- ferroelectric polarization (1)
- ferroelektrische Polarisation (1)
- general relativity (1)
- gravitational waves (1)
- high permittivity (1)
- hohe Permittivität (1)
- holography (1)
- hysteresis (1)
- ice sheet (1)
- komplexe Netzwerke (1)
- kritischer Kollaps (1)
- markov processes (1)
- mathematics education (1)
- molecular motors (1)
- molekulare Motoren (1)
- nanocomposites (1)
- nichtlineare Datenanalyse (1)
- non-volatile memory (1)
- nonlinear dynamics (1)
- nonlinear excited fluorescence (1)
- nonlinear time series analysis (1)
- numerical relativity (1)
- numerische Relativitätstheorie (1)
- organic electronic (1)
- organische Elektronik (1)
- philosophy of science (1)
- physics (1)
- quasars (1)
- raumartige Unendliche (1)
- relativistic hydrodynamics (1)
- relativistische Hydrodynamik (1)
- schwarze Löcher (1)
- science education (1)
- space-like infinity (1)
- space-time geometry (1)
- stability (1)
- state model (1)
- statistical physics (1)
- statistics (1)
- statistische Physik (1)
- surface relief grating (1)
- synchronization (1)
- synthetic eumelanin (1)
- synthetisches Eumelanin (1)
- tensor decompositions (1)
- transient absorption (1)
- vacuum fluctuations (1)
- van der Waals forces (1)
- van der Waals-Kräfte (1)
- wavelength shift (1)
Institute
- Institut für Physik und Astronomie (26) (remove)
Interaction of land surface processes and the atmophere in the Arctic - senitivities and extremes
(2011)
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.
Eumelanin ist ein Fluorophor mit teilweise recht ungewöhnlichen spektralen Eigenschaften. Unter anderem konnten in früheren Veröffentlichungen Unterschiede zwischen dem 1- und 2-photonen-angeregtem Fluoreszenzspektrum beobachtet werden, weshalb im nichtlinearen Anregungsfall ein schrittweiser Anregungsprozess vermutet wurde. Um diese und weitere optische Eigenschaften des Eumelanins besser zu verstehen, wurden in der vorliegenden Arbeit vielfältige messmethodische Ansätze der linearen und nichtlinearen Optik an synthetischem Eumelanin in 0,1M NaOH verfolgt. Aus den Ergebnissen wurde ein Modell abgeleitet, welches die beobachteten photonischen Eigenschaften konsistent beschreibt. In diesem kaskadierten Zustandsmodell (Kaskaden-Modell) wird die aufgenommene Photonenenergie schrittweise von Anregungszuständen hoher Übergangsenergien zu Anregungszuständen niedrigerer Übergangsenergien transferiert. Messungen der transienten Absorption ergaben dominante Anteile mit kurzen Lebensdauern im ps-Bereich und ließen damit auf eine hohe Relaxationsgeschwindigkeit entlang der Kaskade schließen. Durch Untersuchung der nichtlinear angeregten Fluoreszenz von verschieden großen Eumelanin-Aggregaten konnte gezeigt werden, dass Unterschiede zwischen dem linear und nichtlinear angeregten Fluoreszenzspektrum nicht nur durch einen schrittweisen Anregungsprozess bei nichtlinearer Anregung sondern auch durch Unterschiede in den Verhältnissen der Quantenausbeuten zwischen kleinen und großen Aggregaten beim Wechsel von linearer zu nichtlinearer Anregung begründet sein können. Durch Bestimmung des Anregungswirkungsquerschnitts und der Anregungspulsdauer-Abhängigkeit der nichtlinear angeregten Fluoreszenz von Eumelanin konnte jedoch ein schrittweiser 2-Photonen-Anregungsprozess über einen Zwischenzustand mit Lebendsdauern im ps-Bereich nachgewiesen werden.
A key non-destructive technique for analysis, optimization and developing of new functional materials such as sensors, transducers, electro-optical and memory devices is presented. The Thermal-Pulse Tomography (TPT) provides high-resolution three-dimensional images of electric field and polarization distribution in a material. This thermal technique use a pulsed heating by means of focused laser light which is absorbed by opaque electrodes. The diffusion of the heat causes changes in the sample geometry, generating a short-circuit current or change in surface potential, which contains information about the spatial distribution of electric dipoles or space charges. Afterwards, a reconstruction of the internal electric field and polarization distribution in the material is possible via Scale Transformation or Regularization methods. In this way, the TPT was used for the first time to image the inhomogeneous ferroelectric switching in polymer ferroelectric films (candidates to memory devices). The results shows the typical pinning of electric dipoles in the ferroelectric polymer under study and support the previous hypotheses of a ferroelectric reversal at a grain level via nucleation and growth. In order to obtain more information about the impact of the lateral and depth resolution of the thermal techniques, the TPT and its counterpart called Focused Laser Intensity Modulation Method (FLIMM) were implemented in ferroelectric films with grid-shaped electrodes. The results from both techniques, after the data analysis with different regularization and scale methods, are in total agreement. It was also revealed a possible overestimated lateral resolution of the FLIMM and highlights the TPT method as the most efficient and reliable thermal technique. After an improvement in the optics, the Thermal-Pulse Tomography method was implemented in polymer-dispersed liquid crystals (PDLCs) films, which are used in electro-optical applications. The results indicated a possible electrostatic interaction between the COH group in the liquid crystals and the fluorinate atoms of the used ferroelectric matrix. The geometrical parameters of the LC droplets were partially reproduced as they were compared with Scanning Electron Microscopy (SEM) images. For further applications, it is suggested the use of a non-strong-ferroelectric polymer matrix. In an effort to develop new polymerferroelectrets and for optimizing their properties, new multilayer systems were inspected. The results of the TPT method showed the non-uniformity of the internal electric-field distribution in the shaped-macrodipoles and thus suggested the instability of the sample. Further investigation on multilayers ferroelectrets was suggested and the implementation of less conductive polymers layers too.