Tesi: "Relativity (Physics)"

1

Starr, I. M. "Multidimensional relativity". Thesis, University of Leeds, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235269.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

2

Drake, S. P. "Axisymmetric spacetimes in relativity /". Title page, contents and introduction only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phd763.pdf.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

3

Farr, Will M. (Will Meierjurgen). "Numerical relativity from a gauge theory perspective". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62871.

Testo completo

Abstract (sommario):

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2010.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references (p. 121-123).
I present a new method for numerical simulations of general relativistic systems that eliminates constraint violating modes without the need for constraint damping or the introduction of extra dynamical fields. The method is a type of variational integrator. It is based on a discretization of an action for gravity (the Plebański action) on an unstructured mesh that preserves the local Lorentz transformation and diffeomorphism symmetries of the continuous action. Applying Hamilton's principle of stationary action gives discrete field equations on the mesh. For each gauge degree of freedom there is a corresponding discrete constraint; the remaining discrete evolution equations exactly preserve these constraints under time-evolution. I validate the method using simulations of several analytically solvable spacetimes: a weak gravitational wave spacetime, the Schwarzschild spacetime, and the Kerr spacetime.
by Will M. Farr.
Ph.D.

Gli stili APA, Harvard, Vancouver, ISO e altri

4

Sjödin, Robert. "Cosmic strings in general relativity". Thesis, University of Southampton, 2001. https://eprints.soton.ac.uk/50619/.

Testo completo

Abstract (sommario):

In this thesis we examine the properties of Cosmic Strings in the theory of General Relativity. We begin by considering static Cosmic Strings in flat space-time. We derive the field equations for the Cosmic String and show that the solution depends upon a single scaling parameter a which is constructed from the physical constants. Using this result we construct 1-parameter families of solutions which depend on an auxiliary parameter e and which describe the thin-string limit of a Cosmic String. By interpreting these solutions as elements of the simplified Colombeau algebra we may interpret the relativistic energy density Too of the thin string as an element of the Colombeau algebra with delta-function mass-per-unit-length. Furthermore, for a critically coupled Cosmic String the energymomentum tensor in the thin-string limit may be given a distributional interpretation. We also solve the string equations numerically for various values of a. This is done by compactifying the space-time to include infinity as part of the numerical grid and then using a relaxation method to suppress exponentially growing un-physical solutions. In curved space-time we derive the equations for the scalar and vector fields which are now coupled to the geometric variables through Einstein's equations. We again examine the thin-string limit in the Colombeau algebra by considering a 1-parameter family of solutions. W'e derive an expression for the deficit angle in terms of the distributional energy-momentum tensor of the thin string. We use this result to investigate the gravitational lensing properties of the string and relate this to the deficit angle. In the special case of a cone we find the scattering angle is equal to the deficit angle. We also solve the coupled equations numerically using techniques similar to those used in flat space-time. The second part of the thesis involves the dynamics of Cosmic Strings. Einstein's equations then lead to wave equations for both the matter and metric variables. However, the space-time is not asymptotically flat and this leads to problems in applying the appropriate boundary conditions. By using a Geroch transformation it is possible to reformulate the equations in terms of geometrical variables defined on an asymptotically flat (2+l)-dimensional space-time. Three exact vacuum solutions describing gravitational radiation due to Weber-Wheeler, Xanthopoulos and Piran et al. are used to excite the string which is found to oscillate with frequencies which are proportional to the masses of the scalar and vector fields of the string. This is in agreement with the exact results obtained using the linearised equations of the thin dynamic string. The behaviour of the dynamic string is studied by solving the equations numerically using an implicit fully characteristic scheme. The use of the Geroch transformation allows us to compactify the space-time and include null infinity as part of the numerical grid. This enables us to use the correct boundary conditions at infinity and hence suppress un-physical divergent solutions. The code is tested by comparing the results with exact solutions, by checking that it agrees with the static code and by undertaking a time dependent convergence test. The code is found to be accurate, stable and exhibit clear second order convergence.

Gli stili APA, Harvard, Vancouver, ISO e altri

5

O'Donnell, N. "Electromagnetic radiation reaction in general relativity". Thesis, Bucks New University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384632.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

6

Kotze, Jacques. "An introduction to general relativity and entropy bounds". Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/17375.

Testo completo

Abstract (sommario):

Thesis (MSc)--University of Stellenbosch, 2006.
ENGLISH ABSTRACT: Entropy bounds arise from Black hole thermodynamics and are a significant departure from the conventional understanding of the information in a given region. This shift in paradigm is a consequence of the the fact that there is an unexpected relationship between the area and the entropy of a given region of spacetime. Entropy bounds are simplified formulations which are ultimately attempting to be developed into the complete and broad conjecture of the Holographic Principle. This hasn’t been achieved successfully as yet. In this thesis the aim is to introduce how the notion of an entropy bound was first suggested and it’s subsequent development into more robust formulations. The shortcomings of these conjectures are highlighted along with their strengths. A foundational introduction of the mathematical requirements for General Relativity is addressed along with an overview of Einstein’s theory of gravity. This is illustrated by showing the curvature of relative geodesics as being a consequence of gravity. This is contrasted with Newtonian theory where gravity is also shown to manifests as the curvature of relative geodesics. The working background is concluded with a discussion of Einstein’s field equations along with simple and common solutions often used and required.
AFRIKAANSE OPSOMMING: Swartgat Termodinamika impliseer grense op die entropie, en dus inligting, in ’n gegewe ruimtetyd volume, wat ’n drastiese afwyking van die tradisionele denkwyse oor inligting impliseer. Hierdie paradigma skuif het sy oorsprong in ’n onverwagte verband tussen die oppervlakte van, en entropie bevat, in ’n gegewe ruimte tyd volume. Entropie grense is eenvoudige formulerings van hierdie verwantskap wat uiteindelik beslag moet kry in die vollediger en wyer holografiese beginsel. Hierdie doelwit is nog nie bereik nie. Die doel van hierdie tesis is om die oorsprong en verdere formalisering van entropie grense te verduidelik. Beide die sterk en swak punte van die formulerings word bespreek. Algemene relatiwiteits teorie as ’n teorie van gravitasie, sowel as die wiskundige onderbou daarvan, word oorsigtelik bespreek. Die geometries onderbou van gravitasie word geillustreer aan die hand van die buiging van relatiewe geodete. Dit word met Newton se gravitasie teorie vergelyk wat ook in die buiging van relatiewe geodete gemanifesteer word. Hierdie oorsigtelike agtergrond word afgesluit met ’n oorsig van Einstein se vergelykings, asook eenvoudige en algemene oplossings wat dikwels nodig is en gebruik word.

Gli stili APA, Harvard, Vancouver, ISO e altri

7

Sixaba, Vuyile. "Geometry of deformed special relativity". Thesis, Rhodes University, 2018. http://hdl.handle.net/10962/59478.

Testo completo

Abstract (sommario):

We undertake a study of the classical regime in which Planck's constant and Newton's gravitational constant are negligible, but not their ratio, the Planck mass, in hopes that this could possibly lead to testable quantum gravity (QG) effects in a classical regime. In this quest for QG phenomenology we consider modifications of the standard dispersion relation of a free particle known as deformed special relativity (DSR). We try to geometrize DSR to find the geometric origin of the spacetime and momentum space. In particular, we adopt the framework of Hamilton geometry which is set up on phase space, as the cotangent bundle of configuration space in order to derive a purely phase space formulation of DSR. This is necessary when one wants to understand potential links of DSR with modifications of quantum mechanics such as Generalised Uncertainty Principles. It is subsequently observed that space-time and momentum space emerge naturally as curved and intertwined spaces. In conclusion we mention examples and applications of this framework as well as potential future developments.

Gli stili APA, Harvard, Vancouver, ISO e altri

8

Roy, Ian M. "Projective and Ricci collineations in general relativity". Thesis, University of Aberdeen, 1998. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU099861.

Testo completo

Abstract (sommario):

The thesis considers various problems in general relativity concerning projective and Ricci collineations. A result due to Yano in the maximum dimension of the projective algebra on a non-flat space-time is improved using a pointwise classification scheme. The converse of a result, relating Weyl projective vector fields and curvature collineations under certain well defined circumstances, is given. A result is presented showing that, under specified conditions a space-time admitting a proper special projective vector field admits a proper special conformal vector field and vice versa. The work done on Ricci/Matter collineations gives a general mathematical treatment of these vector fields where particular emphasis is placed on decomposable space-times. Problems of differentiability, extendibility, etc are described.

Gli stili APA, Harvard, Vancouver, ISO e altri

9

Walter, Scott. "Henri Poincaré, theoretical Physics, and Relativity Theory in Paris". Wissenschaftlicher Verlag Harri Deutsch, 2011. https://slub.qucosa.de/id/qucosa%3A16256.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

10

Sylvester, Alex J. "Testing General Relativity with Spherical Resonant Mass Detectors". Thesis, University of Louisiana at Lafayette, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10002423.

Testo completo

Abstract (sommario):

Gravitational waves in f(R) gravity excite monopole and m = 0±2 quadrupole resonance modes of a spherical detector. This document reviews the basic ideas of general relativity and gravitational waves, and then applies those concepts to an f( R) gravitational wave. The acoustic response of a GW incident with a spherical detector is reviewed in detail, and the absorption cross section for an f(R) GW impinging on the spherical detector is calculated. Minimum detectable scalar wave amplitudes are explored for the Mario Schenberg detector. The mass of the scalar mode affects its detectability.

Gli stili APA, Harvard, Vancouver, ISO e altri

11

Murdock, David P. 1954. "Proton scattering as a probe of relativity in nuclei". Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/45690.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

12

Baker, Theresa Mary. "Cosmological tests of general relativity". Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:dd5fda2f-d552-4130-839c-71c1a375ef49.

Testo completo

Abstract (sommario):

Understanding the apparent accelerating expansion rate of the universe is a challenge for modern cosmology. One category of explanations is that we are using the wrong gravitational physics to study the observations. Our paradigmatic theory of gravity – Einstein’s theory of General Relativity – may be subsumed by a larger theory. This thesis develops a selection of tools for testing General Relativity and the numerous alternative theories of gravity that have been put forward. I advocate that an elegant and efficient way to test this space of theories is through the use of parameterized frameworks. Inspired by the Parameterized Post-Newtonian framework I develop a new formalism, the Parameterized Post-Friedmann formalism, that aims to unify the linear cosmological perturbation theory of many alternatives to General Relativity. Having introduced the Parameterized Post-Friedmann formalism and demonstrated its application via a suite of examples, I examine several issues surrounding parameterized tests of gravity. I first consider how the structure of a parameterization can influence the constraints obtainable from a given set of data. I then consider how to describe the growth of the large-scale structure of the universe in a parameterized manner. This leads to a convenient tool for calculating corrections to the growth rate of structure in modified theories, which can be used both with the Parameterized Post-Friedmann formalism or independently of it. I present forecasts for how well generalized deviations from General Relativity will be constrained by the next generation of galaxy surveys. Throughout, this thesis aims to take a synoptic approach to theories of modified gravity, rather than focussing on specific models. A question yet to be answered is whether this approach is realistic in practical terms. The final part of this thesis takes the first steps towards an answer.

Gli stili APA, Harvard, Vancouver, ISO e altri

13

Samuelsson, Lars. "Stellar Models in General Relativity". Doctoral thesis, Stockholm : Univ, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-13.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

14

Mena, Filipe Artur Pacheco Neves Carteado. "Inhomogeneous and anisotropic space times in general relativity". Thesis, Queen Mary, University of London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252193.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

15

Hossack, Andrew D. "Sectional curvature and plane waves in general relativity". Thesis, University of Aberdeen, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314609.

Testo completo

Abstract (sommario):

This thesis considers several problems in general relativity which involve the sectional curvature function σ. The causal structure defined by Lorentzian metrics on space-times makes the behaviour of σ more interesting in general relativity than in classical (positive-definite) geometry and comparisons between results in classical and Lorentzian geometry are made which illustrate this point. The thesis as a whole emphasises the geometrical rather than the physical aspects of the theory. There are three principal areas of study contained in this thesis: A theorem by J.L. Synge which relates sectional and Gaussian curvature along geodesics in classical geometry is introduced and generalised to Lorentzian geometry in a straight-forward manner. A result due to J. Beem and P. Parker concerning the existence of non-destructive null directions (along which gravitational tidal accelerations are bounded), in vacuum space-times is extended to arbitrary space-times in an elegant way. It is known that if a sectional curvature function σ is specified on a manifold then it is possible for two distinct, conformally-related generalised plane wave metrics to both give rise to σ. To investigate those symmetries of these space-times that might preserve σ, the concept of a sectional curvature preserving vector field on these plane waves is introduced and it is shown that these vector fields form a subalgebra of the conformal Lie algebra. A basis of this conformal algebra is then computed and used to establish conditions under which non-trivial sectional curvature preserving vector fields may exist. Other subsidiary results are also obtained as a consequence of these investigations.

Gli stili APA, Harvard, Vancouver, ISO e altri

16

Nahmad-Achar, E. "Angular momentum and metric perturbations in general relativity". Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382639.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

17

Cooney, Alan James. "Astrophysical Tests of Gravity Beyond General Relativity". Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/294014.

Testo completo

Abstract (sommario):

The General theory of Relativity (GR) brought gravity into accord with the principles of locality and relativity. Since its discovery it has been preeminent, recognized as the most accurate description of gravity on the many scales where it has been tested. During this period, seemingly radical predictions like the existence of black holes and the expansion of the Universe have been verified and testify to the great leap of insight that GR represented in our understanding of space and time. However not all precision observations of astrophysical systems have yielded easily to interpretation within GR, and with the discovery of cosmic acceleration, there is genuine concern that General Relativity may be incomplete when describing the Universe on the largest sizes imaginable. In this uncertainty, many theoretical models have been proposed. In this thesis we shall first outline the motivation behind a certain subset of these models and the known issues that arise in interpreting these models as alternative theories of gravity. Then focus on one variety of theory the f(R) modifications to gravity. Demonstrating that many of the known instabilities have a common origin and that they are avoided when treating these theories via perturbative constraints. In the second part of this work we examine the astrophysical impact of modifications to gravity, first in the case of high mass neutron stars, then subsequently on corrections to the line profile of neutral hydrogen from violations of the equivalence principle. Finally we explore the phenomenology of modifications to gravity that produce late-Universe acceleration. In particular, what solutions are allowed and what range of accelerations are predicted as a result. Furthermore we explore how a correction to gravity at large scales would impact the growth and evolution of cosmological perturbations.

Gli stili APA, Harvard, Vancouver, ISO e altri

18

Keir, Joseph. "Aspects of stability and instability in general relativity". Thesis, University of Cambridge, 2016. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709537.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

19

Mertens, James B. "Application of Methods from Numerical Relativity to Late-Universe Cosmology". Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1484497200032472.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

20

Holmes, G. "Some algorithmic approaches to exact solutions in general relativity". Thesis, University of Southampton, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373932.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

21

Lonie, David P. "Projective symmetries, holonomy and curvature structure in general relativity". Thesis, University of Aberdeen, 1995. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU082893.

Testo completo

Abstract (sommario):

In the mathematical study of general relativity it is valuable to consider the classification and properties of the metric connection and Riemannian curvature derived from the spacetime metric. The aim of this thesis is to present various results obtained regarding (i) the holonomy groups of simply-connected spacetimes (ii) the problem of deciding if a connection is a metric connection (iii) a sub-class of curvature preserving symmetries and (iv) geodesic preserving symmetries. The holonomy group associated with a spacetime provides a global classification scheme for the metric connection. After the necessary background and definitions, chapter three provides an analysis of the holonomy groups possible in many of the commonly studied classes of spacetime. While every metric is uniquely associated with its metric connection, the converse is not true in general. The question of when a symmetric connection and the curvature derived from it can be associated with a Lorentz signature metric can be addressed via the existence of integrability conditions involving a metric candidate. In chapter four such an analysis is performed in terms of a classification scheme based on the rank and eigenbivector structure of the curvature. The problem is resolved in that the maximum number of such integrability conditions required to guarantee that the connection is a metric connection is given for each (non-trivial) curvature type. Transformations of a spacetime that preserve some geometric quantity or structure are particularly important in general relativity. In chapter five some results regarding transformations that preserve the curvature and its covariant derivatives are presented for spacetimes in which the preservation of the curvature alone is not enough to completely specify the nature of the curvature symmetry.

Gli stili APA, Harvard, Vancouver, ISO e altri

22

Durkee, Mark N. "New approaches to higher-dimensional general relativity". Thesis, University of Cambridge, 2011. https://www.repository.cam.ac.uk/handle/1810/240580.

Testo completo

Abstract (sommario):

This thesis considers various aspects of general relativity in more than four spacetime dimensions. Firstly, I review the generalization to higher dimensions of the algebraic classification of the Weyl tensor and the Newman-Penrose formalism. In four dimensions, these techniques have proved useful for studying many aspects of general relativity, and it is hoped that their higher dimensional generalizations will prove equally useful in the future. Unfortunately, many calculations using the Newman-Penrose formalism can be unnecessarily complicated. To address this, I describe new work introducing a higher-dimensional generalization of the so-called Geroch-Held-Penrose formalism, which allows for a partially covariant reformulation of general relativity. This approach provides great simplifications for many calculations involving spacetimes which admit one or two preferred null directions. The next chapter describes the proof of an important result regarding algebraic classification in higher dimensions. The classification is based upon the existence of a particular null direction that is aligned with the Weyl tensor of the geometry in some appropriate sense. In four dimensions, it is known that a null vector field is such a multiple Weyl aligned null direction (WAND) if and only if it is tangent to a shearfree null geodesic congruence. This is not the case in higher dimensions. However, I have formulated and proved a partial generalization of the result to arbitrary dimension, namely that a spacetime admits a multiple WAND if and only if it admits a geodesic multiple WAND.Moving onto more physical applications, I describe how the formalism that we have developed can be applied to study certain aspects of the stability of extremal black holes in arbitrary dimension. The final chapter of the thesis has a rather different flavour. I give a detailed analysis of the properties of a particular solution to the Einstein equations in five dimensions: the Pomeransky-Sen'kov doubly spinning black ring. I study geodesic motion around this black ring and demonstrate the separability of the Hamilton-Jacobi equation for null, zero energy geodesics. I show that this unexpected separability can be understood in terms of a symmetry described by a conformal Killing tensor on a four dimensional spacetime obtained by a Kaluza-Klein reduction of the original black ring spacetime.

Gli stili APA, Harvard, Vancouver, ISO e altri

23

Boudreaux, Andrew. "An investigation of student understanding of Galilean relativity /". Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/9718.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

24

Tian, Chi. "Exploring General Relativistic Effects in the Universe Through Numerical Relativity". Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1595607121795162.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

25

Ilhan, Ibrahim B. "Dynamics Of Extended Objects In General Relativity". Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610981/index.pdf.

Testo completo

Abstract (sommario):

In this thesis, multipole expansions of mass, momentum and stress density will be made for a body in Newtonian mechanics. Using these definitions
momentum, angular momentum, center of mass, force and torque are defined for N gravitationally interacting isolated bodies. Equations of motions of such a system are derived. Definitions of momentum, angular momentum, center of mass, force and torque are made in a relativistic theory. Dynamical (gravitational) skeleton is defined and the multipole moments of the dynamical skeleton are found. Equations of motion for a test body moving in a gravitational field are derived in terms of the multipole moments. Save the details of the derivations, no originality in this thesis is claimed: it is intended as a review of the subject.

Gli stili APA, Harvard, Vancouver, ISO e altri

26

Corbo, Joel C. (Joel Christopher) 1982. "Superdense objects in general relativity : modeling neutron stars with free quark cores". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/32736.

Testo completo

Abstract (sommario):

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2004.
Includes bibliographical references (p. 65-66).
We present the results of a numerical study of neutron stars made of a color-flavor locked (CFL) quark matter center and a nuclear fluid exterior. CFL quark matter is a theoretical state of matter which may exist at the center of highly dense neutron stars. To verify its existence, we need to make falsifiable predictions about the differences between typical neutron stars and CFL hybrid neutron stars and verify them observationally. This thesis begins this process by modelling the hybrid neutron stars at rest and while undergoing rotation. We show that Newtonian models are insufficient to correctly describe these objects; their treatment must be relativistic. We also put a bound on the upper rotation speed allowed by our approximations. Finally, we note the presence of the backbending instability in our hybrid star model which may constrain the physically accessible parameters of this model. The tools we have developed in this study are a first step in fully investigating the properties of these objects.
by Joel C. Corbo.
S.B.

Gli stili APA, Harvard, Vancouver, ISO e altri

27

Adhyam, Sundararajan Pranesh. "Using perturbation theory to understand the two body problem in general relativity". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/54597.

Testo completo

Abstract (sommario):

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2009.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 171-178).
Binary systems composed of compact objects (neutron stars and black holes) radiate gravitational waves (GWs). The prospect of detecting these GWs using ground and space based experiments has made it imperative to understand the dynamics of such compact binaries. This work describes several advances in our ability to model compact binaries and extract the rich science they encode. A major part of this dissertation focuses on the subset of binaries composed of a massive, central black hole (105 - 10SM®) and a much smaller compact object (1 - 100M®). The emission of gravitational energy from such extreme mass ratio inspirals (EMRIs) forces the separation between the two components to shrink, leading to their merger. We treat the smaller object as a point-like particle on the stationary space-time of the larger black hole. The EMRI problem can be broken down into two related parts: (i) A determination of the inspiral trajectory followed by the smaller object, and (ii) A characterization of the gravitational waveforms that result from such an inspiral. The initial part of this work discusses the development of a numerical algorithm that solves for the GWs that result from the perturbations generated by the smaller object. It accepts any reasonable inspiral trajectory as an input and produces the resulting waveforms with an accuracy greater than 99%. Next, we present a technique to model the part of the inspiral trajectory that immediately precedes the final plunge of smaller object into the massive black hole. Along with earlier research, this enables us to compute the smaller object's complete inspiral trajectory.
(cont.) We now have a versatile toolkit that can model GWs from EMRIs. Finally, we present another application of this work. GWs carry linear momentum away from a binary. Integrating the lost momentum leaves an asymmetric binary with a non-zero recoil velocity after merger. We compute the recoils from EMRIs and extrapolate them to comparable mass binaries. We find that extrapolating perturbation theory gives results that agree well with those from numerical relativity, but require far less computation time.
by Pranesh Adhyam Sundararajan.
Ph.D.

Gli stili APA, Harvard, Vancouver, ISO e altri

28

Janca, Andrew Joseph. "Physical constraints on causality-violating spacetimes in general relativity". NCSU, 2007. http://www.lib.ncsu.edu/theses/available/etd-03252007-193645/.

Testo completo

Abstract (sommario):

The theoretical possibility of global causality violation has long been a problem within general relativity, for there exists a large number of model spacetimes known to admit closed timelike curves, trajectories allowing a timelike observer to return to some point in her own past. However, nearly all such known models have some unphysical feature. These physicality issues rendered causality-violation to the status of an interesting but safely theoretical problem until twenty years ago, when the appearance of a new type of causality-violating model spacetime and the subsequent proliferation of new models admitting closed timelike curves forced the attention of the community to the issue, and made causality violation and its possible physical consequences an active area of research within general relativity. This paper focuses on some of the older causality-violating spacetimes which model matter sources with cylindrical symmetry. By describing how cylindrically-symmetric solutions can be embedded within a spatially bounded and physically realistic body which outwardly has the symmetry of a torus or ring, it is shown that the chief problem of physical plausibility which these older solutions possess can be resolved. The intention is to make these models active candidates for consideration in future experiments to test general relativity's prediction that causality violation is a phenomenon that could be observed in the real world. Attending chapters describe physical systems other than rotating objects that can alter a local observer's experience of time to a substantial extent, including an electrically-charged massive shell slowing time in its interior (though not affecting causality) and a class of trajectories in the Reissner-Nordström background that could in principle allow a timelike observer to reverse her personal arrow of time relative to other observers in the spacetime as a whole. The paper concludes with a discussion of one of the plausibility problems with the `consistency conjectures' which attempt to address some of the apparently paradoxical consequences of time travel.

Gli stili APA, Harvard, Vancouver, ISO e altri

29

Scherr, Rachel Ellen. "An investigation of student understanding of basic concepts in special relativity /". Thesis, Connect to this title online; UW restricted, 2001. http://hdl.handle.net/1773/9681.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

30

Vlasov, Igor. "Reference frames and equations of motion in the first PPN approximation of scaler-tensor and vector-tensor theories of gravity". Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4372.

Testo completo

Abstract (sommario):

Thesis (Ph. D.)--University of Missouri-Columbia, 2006.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (Mar. 1, 2007). Vita. Includes bibliographical references.

Gli stili APA, Harvard, Vancouver, ISO e altri

31

Lin, Yinghua. "Computer aided instruction of special relativity". Virtual Press, 1991. http://liblink.bsu.edu/uhtbin/catkey/774750.

Testo completo

Abstract (sommario):

This thesis creates an small expert system that is based on Einstein's special relativity. The basic knowledge of special relativity and the bases for building an expert system are described. The concepts of special relativity are put into a knowledge base by changing the formulas into rules and facts. The Prolog language was used to develop the expert system. New information can be input that does not contradict the rules and facts already in the database. The system also uses computer graphics to demonstrate the physical concepts of relativity. By using this expert system, one can teach the basic knowledge of special relativity and solve some problems related to frames of reference moving with high speed.
Department of Computer Science

Gli stili APA, Harvard, Vancouver, ISO e altri

32

Negm, Dorry A. "The physical structure of the energy-momentum tensor in general relativity". Thesis, University of Aberdeen, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328743.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

33

Eriksson, Daniel. "Perturbative Methods in General Relativity". Doctoral thesis, Umeå : Department of Physics, Umeå University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1488.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

34

Reid, James Andrew. "Conformal holonomy and theoretical gravitational physics". Thesis, University of Aberdeen, 2014. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=215305.

Testo completo

Abstract (sommario):

Conformal holonomy theory is the holonomy theory of the tractor connection on a conformal manifold. In this thesis, we present the first application of conformal holonomy theory to theoretical physics and determine the conformal holonomy groups/algebras of physically relevant spaces. After recalling some necessary background on conformal structures, tractor bundles and conformal holonomy theory in chapter 1, we begin in chapter 2 by discussing the role of conformal holonomy in the gauge-theoretic MacDowell-Mansouri formulation of general relativity. We show that the gauge algebra of this formulation is uniquely determined by the conformal structure of spacetime itself, in both Lorentzian and Riemannian metric signatures, through the conformal holonomy algebra. We then show that one may construct a MacDowell-Mansouri action functional for scale-invariant gravity, and we discuss a geometric interpretation for the scalar field therein. In chapter 3 we study a class of spacetimes relevant to Maldacena's AdS5=CFT4 correspondence in quantum gravity. It is well known that a Lie group coincidence lies at the heart of this correspondence: the proper isometry group of the bulk precisely matches the conformal group of the boundary. It has previously been proposed that the AdS5=CFT4 correspondence be extended to so-called Poincar e-Einstein spacetimes, which need not be as symmetric as anti-de Sitter space. We show that the conformal holonomy groups of the boundary and bulk furnish such a Lie group coincidence for 5-dimensional Poincar e-Einstein spacetimes in general. We completely characterise this boundary-bulk conformal holonomy matching for the Riemannian theory and present partial results for the Lorentzian theory. In chapter 4 we use the tools developed in the preceding chapters to further the classiification of the conformal holonomy groups of conformally Einstein spaces. Specifically, we determine the conformal holonomy groups of generic neutral signature conformally Einstein 4-manifolds subject to a condition on the conformal holonomy representation. Lastly, in chapter 5, we investigate the conformal holonomy reduction of the Fefferman conformal structures of residual twistor CR manifolds. A sufficient condition for reducible conformal holonomy is that the (Fefferman conformal structure of a) residual twistor CR manifold admit a parallel tractor. We show that this occurs if and only if the residual twistor CR manifold admits a Sasakian structure.

Gli stili APA, Harvard, Vancouver, ISO e altri

35

Van, der Walt Petrus Johannes. "Numerical relativity on cosmological past null cones". Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1002959.

Testo completo

Abstract (sommario):

The observational approach to cosmology is the endeavour to reconstruct the geometry of the Universe using only data that is theoretically verifiable within the causal boundaries of a cosmological observer. Using this approach, it was shown in [36] that given ideal cosmological observations, the only essential assumption necessary to determine the geometry of the Universe is a theory of gravity. Assuming General Relativity, the full set of Einstein field equations (EFEs) can be used to reconstruct the geometry of the Universe using direct observations on the past null cone (PNC) as initial conditions. Observationally and theoretically this is a very ambitious task and therefore, current developments have been restricted to spherically symmetric dust models while only relaxing the usual assumption of homogeneity in the radial direction. These restricted models are important for the development of theoretical foundations and also useful as verification models since they avoid the circularity of verifying what has already been assumed. The work presented in this thesis is the development of such a model where numerical relativity (NR) is used to simulate the observable universe. Similar to the work of Ellis and co-workers [36], a reference frame based on the PNC is used. The reference frame used here, however, is based on that of the characteristic formalism of NR, which has developed for calculating the propagation of gravitational waves. This provides a formalism that is well established in NR, making the use of existing algorithms possible. The Bondi-Sachs coordinates of the characteristic formalism is, however, not suitable for calculations beyond the observer apparent horizon (AH) since the diameter distance used as a radial coordinate becomes multi-valued when the cosmological PNC reconverges in the history of a universe, smaller in the past. With this taken into consideration, the Bondi-Sachs characteristic formalism is implemented for cosmology and the problem approaching the AH is investigated. Further developments address the limitations approaching the AH by introducing a metric based on the Bondi-Sachs metric where the radial coordinate is replaced with an affine parameter. The model is derived with a cosmological constant Λ incorporated into the EFEs where Λ is taken as a parameter of the theory of gravity rather than as a matter source term. Similar to the conventional characteristic formalism, this model consists of a system of differential equations for numerically evolving the EFEs as a characteristic initial value problem (CIVP). A numerical code implemented for the method has been found to be second order convergent. This code enables simulations of different models given identical data on the initial null cone and provides a method to investigate their physical consistency within the causally connected region of our current PNC. These developments closely follow existing 3D schemes developed for gravitational wave simulations, which should make it natural to extend the affine CIVP beyond spherical symmetric simulations. The developments presented in this thesis is an extended version of two papers published earlier.

Gli stili APA, Harvard, Vancouver, ISO e altri

36

Honeycutt, David Carl. "Relativity via a Bergmannian Chronometric in a squared-dimensional hyperspace". Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/27984.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

37

Perry, George Philip. "Isolated systems in general relativity : the gravitational-electrostatic two-body balance problem and the gravitational geon". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0006/NQ34282.pdf.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

38

Boonserm, Petarpa. "Some exact solutions in general relativity : a thesis submitted to the Victoria University of Wellington in fulfilment of the requirements for the degree of Master of Science in Mathematics /". ResearchArchive@Victoria e-Thesis, 2005. http://hdl.handle.net/10063/16.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

39

Fontana, Rodrigo Dal Bosco. "Universos D-dimensionais e soluções de cordas negras". Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-08112013-103203/.

Testo completo

Abstract (sommario):

Durante os últimos 90 anos temos visto o grande esplendor que a teoria da relatividade geral de Einstein alcançou em suas diversas previsões. Esta dissertação é um estudo a respeito desta teoria e suas extrapolações. Falaremos de início acerca da primeira solução das equações de Einstein para buracos negros obtida por Karl Schwarzschild em 1916: o buraco negro esfericamente simétrico e sem carga. Trataremos das possíveis órbitas neste tipo de solução bem como de perturbações gravitacionais e escalares. Ainda utilizando a solução de Schwarzschild, adentraremos os tópicos desenvolvidos recentemente em um tratamento semi-clássico da relatividade: a termodinâmica dos buracos negros. Posteriormente estudaremos as novas teorias com base na relatividade geral, que resolvem o problema da hierarquia buscando por dimensões extras em nosso Universo. Em tal contexto analisamos por exemplo como se comportam os buracos negros nestes Universos com mais do que 4 dimensões. Porém, estudamos perturbações gravitacionais em uma corda negra chegando a averiguar a presença de uma instabilidade para modos com comprimento de onda maiores do que o horizonte da corda (em uma aproximação linear), e demonstramos que em uma das possíveis soluções do problema da Hierarquia (Universos de Randall Sundrum) não existem atalhos gravitacionais mesmo para branas não planas (extrapolação dos Universos de Randall-Sundrum).
Over the last 90 years Einstein`s Theory of General Relativity has had a tremendous success in all its predictions. This dissertation is concerned with the study of this theory and its extrapolations. We begin with the first solution of the Einstein equations for black holes obtained by Karl Schwarzschild at 1916: the spherically symmetric black hole without charge, obtaining the orbits and the scalar and gravitational perturbations around the metric. We also consider the recent developments in black hole thermodynamics via a semiclassical approach to the theory. Subsequently, we study the new theories based on general relativity extrapolations, which solve the hierarchy problem proposing extra dimensions in our Universe. In this context we analyze for example the behavior of black holes in Universes with more than 4 dimensions. Finally, we study the gravitational perturbations in a black string showing the presence of unstable modes with wave length bigger than the black string horizon. We also show that in one of the possible Universes which solve the hierarchy problem there are no gravitational shortcuts even for non-at branes (an extrapolation of Randall-Sundrum Universes).

Gli stili APA, Harvard, Vancouver, ISO e altri

40

Dixon, Thomas S. "Problems for presentism the inconsistency of presentism with the special theory of relativity /". Laramie, Wyo. : University of Wyoming, 2008. http://proquest.umi.com/pqdweb?did=1594478181&sid=2&Fmt=2&clientId=18949&RQT=309&VName=PQD.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

41

Ahmadi, Morteza, e University of Lethbridge Faculty of Arts and Science. "Aspects of black hole physics". Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2006, 2006. http://hdl.handle.net/10133/386.

Testo completo

Abstract (sommario):

In this thesis, aspects of the physics of black holes are reviewed and new results in black hole thermodynamics are presented. First, general black hole solutions of Einstein’s equations of general relativity are mentioned and a proof of conservation law of energy and momentum in general relativity is presented. Aspects of the laws of black hole mechanics and Hawking radiation are then studied. Two proposals which attempt to explain the origin of black hole entropy (the brick wall model and entanglement entropy) are then discussed. Finally, some recent work related to the possible production and detection of black holes in colliders is presented.
viii, 141 leaves ; 29 cm.

Gli stili APA, Harvard, Vancouver, ISO e altri

42

Sarkar, Souvik. "Consequences of Quantum Mechanics in General Relativity". University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535709090287102.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

43

Verma, Ashok Kumar. "Improvement of the planetary ephemerides using spacecraft navigation data and its application to fundamental physics". Thesis, Besançon, 2013. http://www.theses.fr/2013BESA2030/document.

Testo completo

Abstract (sommario):

Les éphémérides planétaires jouent un rôle important pour la navigation des missions spatiales actuelles et la mise en place des missions futures ainsi que la réduction et l'analyse des observations astronomiques les plus précises. Les éphémérides planétaires actuelles (DE, INPOP, EPM)L'objectif de la thèse est d'utiliser des archives de données de missions spatiales passées et présentes et de fournir des outils d'analyse pour l'amélioration de l'éphéméride de données pour l'amélioration de l’éphéméride planétaire planétaire INPOP, ainsi que pour une meilleure utilisation des éphémérides pour effectuer des teste de la physique tels que la relativité générale, les études de la couronne solaire [...]
The planetary ephemerides play a crucial role for spacecraft navigation, mission planning, reductionand analysis of the most precise astronomical observations. The construction of suchephemerides is highly constrained by the tracking observations, in particular range, of the spaceprobes collected by the tracking stations on the Earth. The present planetary ephemerides (DE,INPOP, EPM) are mainly based on such observations. However, the data used by the planetaryephemerides are not the direct raw tracking data, but measurements deduced after the analysisof raw data made by the space agencies and the access to such processed measurements remainsdifficult in terms of availability.The goal of the thesis is to use archives of past and present space missions data independentlyfrom the space agencies, and to provide data analysis tools for the improvement of theplanetary ephemerides INPOP, as well as to use improved ephemerides to perform tests ofphysics such as general relativity, solar corona studies, etc.The first part of the study deals with the analysis of the Mars Global Surveyor (MGS)tracking data as an academic case for understanding. The CNES orbit determination softwareGINS was used for such analysis. The tracking observations containing one-, two-, and threewayDoppler and two-way range are then used to reconstruct MGS orbit precisely and obtainedresults are consistent with those published in the literature. As a supplementary exploitationof MGS, we derived the solar corona model and estimated the average electron density alongthe line of sight separately for slow and fast wind regions. Estimated electron densities arecomparable with the one found in the literature. Fitting the planetary ephemerides, includingadditional data which were corrected for the solar corona perturbations, noticeably improves theextrapolation capability of the planetary ephemerides and the estimation of the asteroid masses(Verma et al., 2013a).The second part of the thesis deals with the complete analysis of the MESSENGER trackingdata. This analysis improved the Mercury ephemeris up to two order of magnitude comparedto any latest ephemerides. Such high precision ephemeris, INPOP13a, is then used to performgeneral relativity tests of PPN-formalism.[...]

Gli stili APA, Harvard, Vancouver, ISO e altri

44

McClune, James C. "Some effects of spacetime curvature in general relativity /". free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9841171.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

45

Panassiti, Antonio. "General relativity limit of Brans-Dicke gravity". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23344/.

Testo completo

Abstract (sommario):

In Brans-Dicke gravity a scalar field non-minimally coupled with the curvature acts as a new gravitational degree of freedom in addition to the usual metric field of General Relativity. Usually, when the coupling ω of the scalar field diverges, the latter approaches a constant and the solutions of the theory reduce to those generated by the Einstein equations with the same energy-momentum tensor as source. However, in the limit ω → ∞, the static and spherically symmetric vacuum solutions, called Brans solutions, do not reduce to the Schwarzschild metric, the only solution of General Relativity with the same type of symmetry. In this work we test their limit with a new method. Unlike the usual way, we use the Brans solutions to take the limit at the level of the equations. Since these are non-linear field equations depending on ω, in principle our procedure could lead to a different outcome. In particular, we take advantage of the Einstein frame formulation of the Brans-Dicke theory and we check if the solutions are able to satisfy the equations of the so called Minimal Geometric Deformation approach. Namely, we study if they can be seen as a geometric deformation - due to the Brans-Dicke scalar - of the Schwarzschild solution. Indeed, the peculiar feature of the geometric deformation is that it is built in such a way to guarantee a clear limit to the vacuum equations of General Relativity. However, we find that the Brans solutions do not meet all the requirements imposed by the structure of the Minimal Geometric Deformation approach. This result supports the conclusion that there is no simple limiting procedure in which the complete Brans-Dicke theory just reduces to General Relativity.

Gli stili APA, Harvard, Vancouver, ISO e altri

46

Bonifacio, Paolo. "Spacetime conformal fluctuations and quantum dephasing". Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=33587.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

47

Dorkenoo, Leggat Alasdair. "Dirac solitons in general relativity and conformal gravity". Thesis, University of St Andrews, 2017. http://hdl.handle.net/10023/12127.

Testo completo

Abstract (sommario):

Static, spherically-symmetric particle-like solutions to the coupled Einstein-Dirac and Einstein-Dirac-Maxwell equations have been studied by Finster, Smoller and Yau (FSY). In their work, FSY left the fermion mass as a parameter set to ±1. This thesis generalises these equations to include the Higgs field, letting the fermion mass become a function through coupling, μ. We discuss the dynamics associated with the Higgs field and find that there exist qualitatively similar solutions to those found by FSY, with well behaved, non-divergent metric components and electrostatic potential, close to the origin, going over to the point-particle solutions for large r; the Schwarzschild or Reissner-Nordström metric, and the Coulomb potential. We then go on to discuss an alternative gravity theory, conformal gravity, (CG), and look for solutions of the CG equations of motion coupled to the Dirac, Higgs and Maxwell equations. We obtain asymptotically nonvanishing, yet fully normalisable Dirac spinor components, resembling those of FSY, and, in the case where charge is included, non-divergent electrostatic potential close to the origin, matching onto the Coulomb potential for large r.

Gli stili APA, Harvard, Vancouver, ISO e altri

48

Stark, Elizabeth. "Gravitoelectromagnetism and the question of stability in general relativity". Monash University, School of Mathematical Sciences, 2004. http://arrow.monash.edu.au/hdl/1959.1/9509.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

49

Henriksson, Johan. "Molecular Quadratic Response Properties with Inclusion of Relativity". Doctoral thesis, Linköping : Department of Physics, Chemistry and Biology, Linköping University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11035.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

50

Diener, Jacobus Petrus Willem. "Relativistic mean-field theory applied to the study of neutron star properties". Thesis, Link to the online version, 2008. http://hdl.handle.net/10019/760.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Tesi sul tema "Relativity (Physics)"

Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili