Gravitational Waves and Binary Black Holes
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Covariant Hamiltonian Formalism for Field Theory: Hamilton-Jacobi
Covariant hamiltonian formalism for field theory: Hamilton-Jacobi equation on the space G Carlo Rovelli Centre de Physique Th´eorique de Luminy, CNRS, Case 907, F-13288 Marseille, EU February 7, 2008 Abstract Hamiltonian mechanics of field theory can be formulated in a generally covariant and background independent manner over a finite dimensional extended configuration space. The physical symplectic structure of the theory can then be defined over a space G of three-dimensional surfaces without boundary, in the extended configuration space. These surfaces provide a preferred over-coordinatization of phase space. I consider the covariant form of the Hamilton-Jacobi equation on G, and a canonical function S on G which is a preferred solution of the Hamilton-Jacobi equation. The application of this formalism to general relativity is equiv- alent to the ADM formalism, but fully covariant. In the quantum domain, it yields directly the Ashtekar-Wheeler-DeWitt equation. Finally, I apply this formalism to discuss the partial observables of a covariant field theory and the role of the spin networks –basic objects in quantum gravity– in the classical theory. arXiv:gr-qc/0207043v2 26 Jul 2002 1 Introduction Hamiltonian mechanics is a clean and general formalism for describing a physi- cal system, its states and its observables, and provides a road towards quantum theory. In its traditional formulation, however, the hamiltonian formalism is badly non covariant. This is a source of problems already for finite dimensional systems. For instance, the notions of state and observable are not very clean in the hamiltonian mechanics of the systems where evolution is given in para- metric form, especially if the evolution cannot be deparametrized (as in certain cosmological models). -
Linearization Instability in Gravity Theories1
Linearization Instability in Gravity Theories1 Emel Altasa;2 a Department of Physics, Middle East Technical University, 06800, Ankara, Turkey. Abstract In a nonlinear theory, such as gravity, physically relevant solutions are usually hard to find. Therefore, starting from a background exact solution with symmetries, one uses the perturbation theory, which albeit approximately, provides a lot of information regarding a physical solution. But even this approximate information comes with a price: the basic premise of a perturbative solution is that it should be improvable. Namely, by going to higher order perturbation theory, one should be able to improve and better approximate the physical problem or the solution. While this is often the case in many theories and many background solutions, there are important cases where the linear perturbation theory simply fails for various reasons. This issue is well known in the context of general relativity through the works that started in the early 1970s, but it has only been recently studied in modified gravity theories. This thesis is devoted to the study of linearization instability in generic gravity theories where there are spurious solutions to the linearized equations which do not come from the linearization of possible exact solutions. For this purpose we discuss the Taub charges, arXiv:1808.04722v2 [hep-th] 2 Sep 2018 the ADT charges and the quadratic constraints on the linearized solutions. We give the three dimensional chiral gravity and the D dimensional critical gravity as explicit examples and give a detailed ADM analysis of the topologically massive gravity with a cosmological constant. 1This is a Ph.D. -
Wave Extraction in Numerical Relativity
Doctoral Dissertation Wave Extraction in Numerical Relativity Dissertation zur Erlangung des naturwissenschaftlichen Doktorgrades der Bayrischen Julius-Maximilians-Universitat¨ Wurzburg¨ vorgelegt von Oliver Elbracht aus Warendorf Institut fur¨ Theoretische Physik und Astrophysik Fakultat¨ fur¨ Physik und Astronomie Julius-Maximilians-Universitat¨ Wurzburg¨ Wurzburg,¨ August 2009 Eingereicht am: 27. August 2009 bei der Fakultat¨ fur¨ Physik und Astronomie 1. Gutachter:Prof.Dr.Karl Mannheim 2. Gutachter:Prof.Dr.Thomas Trefzger 3. Gutachter:- der Dissertation. 1. Prufer¨ :Prof.Dr.Karl Mannheim 2. Prufer¨ :Prof.Dr.Thomas Trefzger 3. Prufer¨ :Prof.Dr.Thorsten Ohl im Promotionskolloquium. Tag des Promotionskolloquiums: 26. November 2009 Doktorurkunde ausgehandigt¨ am: Gewidmet meinen Eltern, Gertrud und Peter, f¨urall ihre Liebe und Unterst¨utzung. To my parents Gertrud and Peter, for all their love, encouragement and support. Wave Extraction in Numerical Relativity Abstract This work focuses on a fundamental problem in modern numerical rela- tivity: Extracting gravitational waves in a coordinate and gauge independent way to nourish a unique and physically meaningful expression. We adopt a new procedure to extract the physically relevant quantities from the numerically evolved space-time. We introduce a general canonical form for the Weyl scalars in terms of fundamental space-time invariants, and demonstrate how this ap- proach supersedes the explicit definition of a particular null tetrad. As a second objective, we further characterize a particular sub-class of tetrads in the Newman-Penrose formalism: the transverse frames. We establish a new connection between the two major frames for wave extraction: namely the Gram-Schmidt frame, and the quasi-Kinnersley frame. Finally, we study how the expressions for the Weyl scalars depend on the tetrad we choose, in a space-time containing distorted black holes. -
3+1 Formalism and Bases of Numerical Relativity
3+1 Formalism and Bases of Numerical Relativity Lecture notes Eric´ Gourgoulhon Laboratoire Univers et Th´eories, UMR 8102 du C.N.R.S., Observatoire de Paris, Universit´eParis 7 arXiv:gr-qc/0703035v1 6 Mar 2007 F-92195 Meudon Cedex, France [email protected] 6 March 2007 2 Contents 1 Introduction 11 2 Geometry of hypersurfaces 15 2.1 Introduction.................................... 15 2.2 Frameworkandnotations . .... 15 2.2.1 Spacetimeandtensorfields . 15 2.2.2 Scalar products and metric duality . ...... 16 2.2.3 Curvaturetensor ............................... 18 2.3 Hypersurfaceembeddedinspacetime . ........ 19 2.3.1 Definition .................................... 19 2.3.2 Normalvector ................................. 21 2.3.3 Intrinsiccurvature . 22 2.3.4 Extrinsiccurvature. 23 2.3.5 Examples: surfaces embedded in the Euclidean space R3 .......... 24 2.4 Spacelikehypersurface . ...... 28 2.4.1 Theorthogonalprojector . 29 2.4.2 Relation between K and n ......................... 31 ∇ 2.4.3 Links between the and D connections. .. .. .. .. .. 32 ∇ 2.5 Gauss-Codazzirelations . ...... 34 2.5.1 Gaussrelation ................................. 34 2.5.2 Codazzirelation ............................... 36 3 Geometry of foliations 39 3.1 Introduction.................................... 39 3.2 Globally hyperbolic spacetimes and foliations . ............. 39 3.2.1 Globally hyperbolic spacetimes . ...... 39 3.2.2 Definition of a foliation . 40 3.3 Foliationkinematics .. .. .. .. .. .. .. .. ..... 41 3.3.1 Lapsefunction ................................. 41 3.3.2 Normal evolution vector . 42 3.3.3 Eulerianobservers ............................. 42 3.3.4 Gradients of n and m ............................. 44 3.3.5 Evolution of the 3-metric . 45 4 CONTENTS 3.3.6 Evolution of the orthogonal projector . ....... 46 3.4 Last part of the 3+1 decomposition of the Riemann tensor . -
Gravitational Waves
Bachelor Project: Gravitational Waves J. de Valen¸caunder supervision of J. de Boer 4th September 2008 Abstract The purpose of this article is to investigate the concept of gravita- tional radiation and to look at the current research projects designed to measure this predicted phenomenon directly. We begin by stat- ing the concepts of general relativity which we will use to derive the quadrupole formula for the energy loss of a binary system due to grav- itational radiation. We will test this with the famous binary pulsar PSR1913+16 and check the the magnitude and effects of the radiation. Finally we will give an outlook to the current and future experiments to measure the effects of the gravitational radiation 1 Contents 1 Introduction 3 2 A very short introduction to the Theory of General Relativ- ity 4 2.1 On the left-hand side: The energy-momentum tensor . 5 2.2 On the right-hand side: The Einstein tensor . 6 3 Working with the Einstein equations of General Relativity 8 4 A derivation of the energy loss due to gravitational radiation 10 4.1 Finding the stress-energy tensor . 10 4.2 Rewriting the quadrupole formula to the TT gauge . 13 4.3 Solving the integral and getting rid of the TT’s . 16 5 Testing the quadrupole radiation formula with the pulsar PSR 1913 + 16 18 6 Gravitational wave detectors 24 6.1 The effect of a passing gravitational wave on matter . 24 6.2 The resonance based wave detector . 26 6.3 Interferometry based wave detectors . 27 7 Conclusion and future applications 29 A The Einstein summation rule 32 B The metric 32 C The symmetries in the Ricci tensor 33 ij D Transversal and traceless QTT 34 2 1 Introduction Waves are a well known phenomenon in Physics. -
Extraction of Gravitational Waves in Numerical Relativity
Extraction of Gravitational Waves in Numerical Relativity Nigel T. Bishop Department of Mathematics, Rhodes University, Grahamstown 6140, South Africa email: [email protected] http://www.ru.ac.za/mathematics/people/staff/nigelbishop Luciano Rezzolla Institute for Theoretical Physics, 60438 Frankfurt am Main, Germany Frankfurt Institute for Advanced Studies, 60438 Frankfurt am Main, Germany email: [email protected] http://astro.uni-frankfurt.de/rezzolla July 5, 2016 Abstract A numerical-relativity calculation yields in general a solution of the Einstein equations including also a radiative part, which is in practice computed in a region of finite extent. Since gravitational radiation is properly defined only at null infinity and in an appropriate coordinate system, the accurate estimation of the emitted gravitational waves represents an old and non-trivial problem in numerical relativity. A number of methods have been developed over the years to \extract" the radiative part of the solution from a numerical simulation and these include: quadrupole formulas, gauge-invariant metric perturbations, Weyl scalars, and characteristic extraction. We review and discuss each method, in terms of both its theoretical background as well as its implementation. Finally, we provide a brief comparison of the various methods in terms of their inherent advantages and disadvantages. arXiv:1606.02532v2 [gr-qc] 4 Jul 2016 1 Contents 1 Introduction 4 2 A Quick Review of Gravitational Waves6 2.1 Linearized Einstein equations . .6 2.2 Making sense of the TT gauge . .9 2.3 The quadrupole formula . 12 2.3.1 Extensions of the quadrupole formula . 14 3 Basic Numerical Approaches 17 3.1 The 3+1 decomposition of spacetime . -
Einstein's Quadrupole Formula from the Kinetic-Conformal Horava Theory
Einstein’s quadrupole formula from the kinetic-conformal Hoˇrava theory Jorge Bellor´ına,1 and Alvaro Restucciaa,b,2 aDepartment of Physics, Universidad de Antofagasta, 1240000 Antofagasta, Chile. bDepartment of Physics, Universidad Sim´on Bol´ıvar, 1080-A Caracas, Venezuela. [email protected], [email protected] Abstract We analyze the radiative and nonradiative linearized variables in a gravity theory within the familiy of the nonprojectable Hoˇrava theories, the Hoˇrava theory at the kinetic-conformal point. There is no extra mode in this for- mulation, the theory shares the same number of degrees of freedom with general relativity. The large-distance effective action, which is the one we consider, can be given in a generally-covariant form under asymptotically flat boundary conditions, the Einstein-aether theory under the condition of hypersurface orthogonality on the aether vector. In the linearized theory we find that only the transverse-traceless tensorial modes obey a sourced wave equation, as in general relativity. The rest of variables are nonradiative. The result is gauge-independent at the level of the linearized theory. For the case of a weak source, we find that the leading mode in the far zone is exactly Einstein’s quadrupole formula of general relativity, if some coupling constants are properly identified. There are no monopoles nor dipoles in arXiv:1612.04414v2 [gr-qc] 21 Jul 2017 this formulation, in distinction to the nonprojectable Horava theory outside the kinetic-conformal point. We also discuss some constraints on the theory arising from the observational bounds on Lorentz-violating theories. 1 Introduction Gravitational waves have recently been detected [1, 2, 3]. -
ADM Formalism with G and Λ Variable
Outline of the talk l Quantum Gravity and Asymptotic Safety in Q.G. l Brief description of Lorentian Asymptotic Safety l ADM formalism with G and Λ variable. l Cosmologies of the Sub-Planck era l Bouncing and Emergent Universes. l Conclusions. QUANTUM GRAVITY l Einstein General Relativity works quite well for distances l≫lPl (=Planck lenght). l Singularity problem and the quantum mechanical behavour of matter-energy at small distance suggest a quantum mechanical behavour of the gravitational field (Quantum Gravity) at small distances (High Energy). l Many different approaches to Quantum Gravity: String Theory, Loop Quantum Gravity, Non-commutative Geometry, CDT, Asymptotic Safety etc. l General Relativity is considered an effective theory. It is not pertubatively renormalizable (the Newton constant G has a (lenght)-2 dimension) QUANTUM GRAVITY l Fundamental theories (in Quantum Field Theory), in general, are believed to be perturbatively renormalizable. Their infinities can be absorbed by redefining their parameters (m,g,..etc). l Perturbative non-renormalizability: the number of counter terms increase as the loops orders do, then there are infinitely many parameters and no- predictivity of the theory. l There exist fundamental (=infinite cut off limit) theories which are not “perturbatively non renormalizable (along the line of Wilson theory of renormalization). l They are constructed by taking the infinite-cut off limit (continuum limit) at a non-Gaussinan fixed point (u* ≠ 0, pert. Theories have trivial Gaussian point u* = 0). ASYMPTOTIC SAFETY l The “Asymptotic safety” conjecture of Weinberg (1979) suggest to run the coupling constants of the theory, find a non (NGFP)-Gaussian fixed point in this space of parameters, define the Quantum theory at this point. -
A Semiclassical Intrinsic Canonical Approach to Quantum Gravity
Semi-classical Intrinsic Gravity A semiclassical intrinsic canonical approach to quantum gravity J¨urgenRenn∗ and Donald Salisbury+ Austin College, Texas+ Max Planck Institute for the History of Science, Berlin+∗ Reflections on the Quantum Nature of Space and Time Albert Einstein Institute, Golm, Germany, November 28, 2012 Semi-classical Intrinsic Gravity Overview 1 Introduction 2 An historically motivated heuristics 3 The standard approach to semiclassical canonical quantization 4 Limitations of the standard approach to semiclassical canonical quantization 5 History of constrained Hamiltonian dynamics 6 A bridge between spacetime and phase space formulations of general relativity 7 Intrinsic coordinates and a Hamilton-Jacobi approach to semi-classical quantum gravity Semi-classical Intrinsic Gravity Introduction 1. INTRODUCTION Semi-classical Intrinsic Gravity Introduction Introduction The twentieth century founders of quantum mechanics drew on a rich classical mechanical tradition in their effort to incorporate the quantum of action into their deliberations. The phase space formulation of mechanics proved to be the most amenable to adaptation, and in fact the resulting quantum theory proved to not be so distant from the classical theory within the framework of the associated Hamilton-Jacobi theory. Semi-classical Intrinsic Gravity Introduction Introduction We will briefly review these efforts and their relevance to attempts over the past few decades to construct a quantum theory of gravity. We emphasize in our overview the heuristic role of the action, and in referring to observations of several of the historically important players we witness frequent expressions of hope, but also misgivings and even misunderstandings that have arisen in attempts to apply Hamilton-Jacobi techniques in a semi-classical approach to quantum gravity. -
Post-Newtonian Approximations and Applications
Monash University MTH3000 Research Project Coming out of the woodwork: Post-Newtonian approximations and applications Author: Supervisor: Justin Forlano Dr. Todd Oliynyk March 25, 2015 Contents 1 Introduction 2 2 The post-Newtonian Approximation 5 2.1 The Relaxed Einstein Field Equations . 5 2.2 Solution Method . 7 2.3 Zones of Integration . 13 2.4 Multi-pole Expansions . 15 2.5 The first post-Newtonian potentials . 17 2.6 Alternate Integration Methods . 24 3 Equations of Motion and the Precession of Mercury 28 3.1 Deriving equations of motion . 28 3.2 Application to precession of Mercury . 33 4 Gravitational Waves and the Hulse-Taylor Binary 38 4.1 Transverse-traceless potentials and polarisations . 38 4.2 Particular gravitational wave fields . 42 4.3 Effect of gravitational waves on space-time . 46 4.4 Quadrupole formula . 48 4.5 Application to Hulse-Taylor binary . 52 4.6 Beyond the Quadrupole formula . 56 5 Concluding Remarks 58 A Appendix 63 A.1 Solving the Wave Equation . 63 A.2 Angular STF Tensors and Spherical Averages . 64 A.3 Evaluation of a 1PN surface integral . 65 A.4 Details of Quadrupole formula derivation . 66 1 Chapter 1 Introduction Einstein's General theory of relativity [1] was a bold departure from the widely successful Newtonian theory. Unlike the Newtonian theory written in terms of fields, gravitation is a geometric phenomena, with space and time forming a space-time manifold that is deformed by the presence of matter and energy. The deformation of this differentiable manifold is characterised by a symmetric metric, and freely falling (not acted on by exter- nal forces) particles will move along geodesics of this manifold as determined by the metric. -
The Efficiency of Gravitational Bremsstrahlung Production in The
The Efficiency of Gravitational Bremsstrahlung Production in the Collision of Two Schwarzschild Black Holes R. F. Aranha∗ Centro Brasileiro de Pesquisas F´ısicas-CFC Rua Dr. Xavier Sigaud 150, Urca, Rio de Janeiro CEP 22290-180-RJ, Brazil H. P. de Oliveira† Instituto de F´ısica - Universidade do Estado do Rio de Janeiro CEP 20550-013 Rio de Janeiro, RJ, Brazil I. Dami˜ao Soares‡ Centro Brasileiro de Pesquisas F´ısicas Rua Dr. Xavier Sigaud 150, Urca, Rio de Janeiro CEP 22290-180-RJ, Brazil E. V. Tonini§ Centro Federal de Educa¸c˜ao Tecnol´ogica do Esp´ırito Santo Avenida Vit´oria, 1729, Jucutuquara, Vit´oria CEP 29040-780-ES, Brazil (Dated: October 28, 2018) We examine the efficiency of gravitational bremsstrahlung production in the process of head-on collision of two boosted Schwarzschild black holes. We constructed initial data for the character- istic initial value problem in Robinson-Trautman spacetimes, that represent two instantaneously stationary Schwarzschild black holes in motion towards each other with the same velocity. The Robinson-Trautman equation was integrated for these initial data using a numerical code based on the Galerkin method. The final resulting configuration is a boosted black hole with Bondi mass greater than the sum of the individual mass of each initial black hole. Two relevant aspects of the process are presented. The first relates the efficiency ∆ of the energy extraction by gravitational wave emission to the mass of the final black hole. This relation is fitted by a distribution function of non-extensive thermostatistics with entropic parameter q 1/2; the result extends and validates analysis based on the linearized theory of gravitational wa≃ve emission. -
Einstein's Discovery of Gravitational Waves 1916-1918
1 Einstein’s Discovery of Gravitational Waves 1916-1918 Galina Weinstein 12/2/16 In his 1916 ground-breaking general relativity paper Einstein had imposed a restrictive coordinate condition; his field equations were valid for a system –g = 1. Later, Einstein published a paper on gravitational waves. The solution presented in this paper did not satisfy the above restrictive condition. In his gravitational waves paper, Einstein concluded that gravitational fields propagate at the speed of light. The solution is the Minkowski flat metric plus a small disturbance propagating in a flat space-time. Einstein calculated the small deviation from Minkowski metric in a manner analogous to that of retarded potentials in electrodynamics. However, in obtaining the above derivation, Einstein made a mathematical error. This error caused him to obtain three different types of waves compatible with his approximate field equations: longitudinal waves, transverse waves and a new type of wave. Einstein added an Addendum in which he suggested that in a system –g = 1 only waves of the third type occur and these waves transport energy. He became obsessed with his system –g = 1. Einstein’s colleagues demonstrated to him that in the coordinate system –g = 1 the gravitational wave of a mass point carry no energy, but Einstein tried to persuade them that he had actually not made a mistake in his gravitational waves paper. Einstein, however, eventually accepted his colleagues results and dropped the restrictive condition –g = 1. This finally led him to discover plane transverse gravitational waves. Already in 1913, at the eighty-fifth congress of the German Natural Scientists and Physicists in Vienna, Einstein started to think about gravitational waves when he worked on the Entwurf theory.