In this work, we study the theory of linearized gravity and prove the linear stability of Schwarzschild black holes as solutions of the vacuum Einstein equations. In particular, we prove that solutions to the linearized vacuum Einstein equations centered at a Schwarzschild metric, with suitably regular initial data, remain uniformly bounded and decay to a linearized Kerr metric on the exterior region. Our method employs Hodge decomposition to split the solution into closed and co-closed portions, respectively identified with even-parity and odd-parity solutions in the physics literature. For both portions, we derive Regge-Wheeler type equations for decoupled, gauge-invariant quantities at the level of perturbed connection coefficients. A general framework for the analysis of Regge-Wheeler type equations is presented, identifying sufficient conditions for decay estimates. With the choice of an appropriate gauge in each of the two portions, such decay estimates on these decoupled quantities are used to establish decay of the linearized metric coefficients, completing the proof of linear stability. The initial value problem is formulated on Cauchy data sets, complementing the work of Dafermos-Holzegel-Rodnianski [6], where the linear stability of Schwarzschild is established for characteristic initial data sets.

Supermassive black hole binaries (SMBHBs) are the natural consequence of galaxy mergers and should form frequently in galactic nuclei. Especially at sub-parsec separations, where the binary evolution is slow, SMBHBs should be fairly abundant. However, the observational evidence remains elusive. In this thesis, we focus on periodic variability of quasars as a potential signature of compact SMBHBs. First, we present a systematic search for periodic variability in the photometric database of the Palomar Transient Factory. Our search in a large sample of ~35,000 quasars returned 50 candidates, 33 of which remain significant after the reanalysis of extended light curves including data from the Catalina Real-Time Transient Survey and the intermediate PTF. Our candidates have periods of a few hundred days. Next, we focus on independent signatures that could verify the binary nature of the candidates. We present a case study of quasar PKS 1302-102, the first candidate that emerged from the large time-domain surveys. We search for multiple periodic components in the variability with a characteristic frequency pattern predicted by hydrodynamical simulations of circumbinary disks. We do not find compelling evidence for a secondary period. Additionally, in compact SMBHBs, relativistic Doppler boost should be significant and may dominate the variability. This model was suggested as a smoking-gun signature for quasar PKS 1302-102, since it is not expected in quasars with a single BH and it offers a robust prediction, which can be tested with multi-wavelength data. With a control sample of non-periodic quasars, we test whether this signature is distinct from the intrinsic multi-wavelength variability of quasars. We concluded that the Doppler boost does not provide a sharp test for SMBHBs.

Higher dimensional black holes are studied in the extra large dimensions scenario. Bulk fermion quasi-normal modes and bulk fermion Hawking emission is calculated. It is found that bulk emission dominates brane emission for d > 5. / To address the Planck phase an effective field theory is investigated. Lepton family number violating processes are elucidated and the corrections to the muon magnetic moment from these channels are calculated. Bounds are placed on the couplings of the theory. / A discrete symmetry between quarks and leptons, and left- right- chirality fields, is orbifolded in 5 dimensions. Using split fermions a one generational standard model extension is found. / An investigation of entanglement in black holes and accelerated motion is presented. It is found that in a certain system the acceleration between two spinors enhances the rate of their disentanglement.

In the following, we build on previous work done on higher derivative gravity, in particular Lovelock gravity. The latter is a family of theories in higher space-time dimensions in which interactions involving higher powers of curvature are introduced, but the equations of motion remain second order in derivatives. We develop a new theory involving cubic terms in the curvature. We then show that the equations of motion for graviton fluctuations remain second order. The curvature cubed term is shown not to be a topological object, contrary to the belief that dimensionally extended Euler densities provided the only stable dimensionally continued theories of gravity (Lovelock gravity). Black hole solutions are studied in this new gravitational framework.

In the following, we build on previous work done on higher derivative gravity, in particular Lovelock gravity. The latter is a family of theories in higher space-time dimensions in which interactions involving higher powers of curvature are introduced, but the equations of motion remain second order in derivatives. We develop a new theory involving cubic terms in the curvature. We then show that the equations of motion for graviton fluctuations remain second order. The curvature cubed term is shown not to be a topological object, contrary to the belief that dimensionally extended Euler densities provided the only stable dimensionally continued theories of gravity (Lovelock gravity). Black hole solutions are studied in this new gravitational framework.

This thesis deals with glued laminated beams with holes. Different hole geometries, circular and quadratic,  and reinforcement methods were investigated. A total of 24 tests were performed using two types of reinforcements (glass fiber and plywood) and testing unreinforced beam. During testing of the beams without reinforcement a contact free deformation measurement system was used to capture the deformation pattern. A commercial finite element software package was used to perform numerical calculations of the response of the beams. The FE-analyses were also compared with the experimental results. The test results showed that the reinforcement with plywood was more efficient than the reinforcement with glass fiber. In addition, the two hole geometries showed different failure behaviors. The beams with quadratic holes showed a less brittle behavior, although at a lower load level than the beams with circular holes. / Denna rapport behandlar limträbalkar med hål. Olika hålgeometrier, cirkulära och kvadratiska hål, och olika metoder att förstärka balkarna vid hålet undersöktes. Totalt 24 enskilda provningar genomfördes med två olika förstärkningsmetoder (glasfiber och plywood) samt med balkar utan förstärkning. Vid provning av de oförstärkta balkarna användes ett system för beröringsfri deformationsmätning för att få en bild av deformationsmönstret. Ett kommersiellt finita elementprogram användes också för att analysera balkarnas respons och för att jämföra med provningsresultaten. Provningarna visade att förstärkningen med plywood var effektivare än förstärkningen med glasfiber. Vidare uppvisade de olika hålgeometrierna olika brottbeteenden, där de kvadratiska hålen gav mindre spröda brott, dock vid en i genomsnitt lägre brottlast än de cirkulära hålen.

We operated focus ion beam instrument (FIB) to etch array of cylindrical holes, with the diameter smaller than the wavelength of visible, on the sliver film. The sample was probed with the tungsten light source and the transmission spectrum of visible-NIR range was recorded with traix550 spectrometer with a cooling CCD. The optical extraordinary properties, such as the light can be transmitted through the holes array with the diameter of the hole smaller than the wavelength of the incident light and the enhancement of the efficiency, of the transmission of the subwavelength holes array were discussed. In this study, the factors affected the transmission spectrum of the subwavelength hole array, e.g.: the arrangement of the holes array, the material of the thin film, the diameter of the hole¡Kand so on, were researched. Besides, we modulated the effective dielectric property of the cavity of the subwavelength holes with the thermal evaporation method. It was pointed out that effective dielectric property of the cavity also influenced the optical properties of extraordinary transmission spectrum. We believe that our research was helpful to understand the physical properties of the subwavelength holes array.

<p>This thesis deals with glued laminated beams with holes. Different hole geometries, circular and quadratic,  and reinforcement methods were investigated. A total of 24 tests were performed using two types of reinforcements (glass fiber and plywood) and testing unreinforced beam. During testing of the beams without reinforcement a contact free deformation measurement system was used to capture the deformation pattern. A commercial finite element software package was used to perform numerical calculations of the response of the beams. The FE-analyses were also compared with the experimental results. The test results showed that the reinforcement with plywood was more efficient than the reinforcement with glass fiber. In addition, the two hole geometries showed different failure behaviors. The beams with quadratic holes showed a less brittle behavior, although at a lower load level than the beams with circular holes.</p> / <p> </p><p>Denna rapport behandlar limträbalkar med hål. Olika hålgeometrier, cirkulära och kvadratiska hål, och olika metoder att förstärka balkarna vid hålet undersöktes. Totalt 24 enskilda provningar genomfördes med två olika förstärkningsmetoder (glasfiber och plywood) samt med balkar utan förstärkning. Vid provning av de oförstärkta balkarna användes ett system för beröringsfri deformationsmätning för att få en bild av deformationsmönstret. Ett kommersiellt finita elementprogram användes också för att analysera balkarnas respons och för att jämföra med provningsresultaten. Provningarna visade att förstärkningen med plywood var effektivare än förstärkningen med glasfiber. Vidare uppvisade de olika hålgeometrierna olika brottbeteenden, där de kvadratiska hålen gav mindre spröda brott, dock vid en i genomsnitt lägre brottlast än de cirkulära hålen.</p>

Thesis (Ph. D.)--University of Alberta, 2009. / Title from pdf file main screen (viewed on Jan. 5, 2010). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Department of Physics, University of Alberta." Includes bibliographical references.

Thesis (Ph. D.)--Open University. BLDSC no. DXN041011.