Aspectos De Relatividade Numérica Campos Escalares E Estrelas De Nêutrons
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
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 . -
Graduate Student Research Day 2010 Florida Atlantic University
Graduate Student Research Day 2010 Florida Atlantic University CHARLES E. SCHMIDT COLLEGE OF SCIENCE Improvements to Moving Puncture Initial Data and Analysis of Gravitational Waveforms using the BSSN Formalism on the BAM Code George Reifenberger Charles E. Schmidt College of Science, Florida Atlantic University Faculty Advisor: Dr. Wolfgang Tichy Numerical relativity has only recently been able to simulate the creation of gravitational wave signatures through techniques concerning both the natural complexities of general relativity and the computational requirements needed to obtain significant accuracies. These gravitational wave signatures will be used as templates for detection. The need to develop better results has divided the field into specific areas of code development, one of which involves improvement on the construction of binary black hole initial data. Gravitational waves are a prediction of general relativity, however none have currently been observed experimentally. The search for gravitational wave signatures from binary black hole mergers has required many sub-disciplines of general relativity to contribute to the effort; numerical relativity being one of these. Assuming speeds much smaller than the speed of light Post-Newtonian approximations are introduced into initial data schemes. Evolution of this initial data using the BSSN formalism has approximately satisfied constraint equations of General Relativity to produce probable gravitational wave signatures. Analysis of data convergence and behavior of physical quantities shows appropriate behavior of the simulation and allows for the wave signatures to be considered for template inclusion. High order convergence of our data validates the accuracy of our code, and the wave signatures produced can be used as an improved foundation for more physical models. -
Causes of Poor Performance in West African School Certificate
Ogundele GA et al.; Sch. J. Arts. Humanit. Soc. Sci. 2014; 2(5B):670-676. Scholars Journal of Arts, Humanities and Social Sciences ISSN 2347-5374 (Online) Sch. J. Arts Humanit. Soc. Sci. 2014; 2(5B):670-676 ISSN 2347-9493 (Print) ©Scholars Academic and Scientific Publishers (SAS Publishers) (An International Publisher for Academic and Scientific Resources) Causes of Poor Performance in West African School Certificate Examination (WASCE) in Nigeria Ogundele, Gbenga Alexander1, Olanipekun, Shola Sunday2, Aina, Jacob Kola3 1Department of Metal Work, 2General Studies Education Department, 3Physics Education Department, College of Education (Tech.), Lafiagi, P.M.B. 001, Kwara State, Nigeria. *Corresponding Author: Aina, Jacob Kola Email: Abstract: This is a review paper that cantered on poor academic performance generally in the West Africa Senior School Certificate Examination which has become a great concern to various stakeholders in the educational sector, most especially in Nigeria. The paper argued that mass failure of students in public examinations could be traced to several factors that can be compartmentalized into the domains of parents, students, teachers, schools, the language of instruction, government and the society among others. In other words, the causes of mass failure of students in public examinations are multi-dimensional in nature. The paper concluded that mass failure of students in public examinations constitutes wastage on investment in secondary education. The paper recommended that since academic performance is a virile instrument to the national development of any nation; all concerned stakeholders must be responsive to their roles in order to restore hope to the current grotesque academic performance of students in WAEC in Nigeria. -
Status of Numerical Relativity: from My Personal Point of View Masaru Shibata (U
Status of Numerical Relativity: From my personal point of view Masaru Shibata (U. Tokyo) 1 Introduction 2 General issues in numerical relativity 3 Current status of implementation 4 Some of our latest numerical results: NS-NS merger & Stellar core collapse 5 Summary & perspective 1: Introduction: Roles in NR A To predict gravitational waveforms: Two types of gravitational-wave detectors work now or soon. h Space Interferometer Ground Interferometer LISA LIGO/VIRGO/ Physics of GEO/TAMA SMBH BH-BH SMBH/SMBH NS-NS SN Frequency 0.1mHz 0.1Hz 10Hz 1kHz Templates (for compact binaries, core collapse, etc) should be prepared B To simulate Astrophysical Phenomena e.g. Central engine of GRBs = Stellar-mass black hole + disks (Probably) NS-NS merger BH-NS merger ? Best theoretical approach Stellar collapse of = Simulation in GR rapidly rotating star C To discover new phenomena in GR In the past 20 years, community has discovered e.g., 1: Critical phenomena (Choptuik) 2: Toroidal black hole (Shapiro-Teukolsky) 3: Naked singularity formation (Nakamura, S-T) GR phenomena to be simulated ASAP ・ NS-NS / BH-NS /BH-BH mergers (Promising GW sources/GRB) ・ Stellar collapse of massive star to a NS/BH (Promising GW sources/GRB) ・ Nonaxisymmetric dynamical instabilities of rotating NSs (Promising GW sources) ・ …. In general, 3D simulations are necessary 2 Issues: Necessary elements for GR simulations • Einstein’s evolution equations solver • GR Hydrodynamic equations solver • Appropriate gauge conditions (coordinate conditions) • Realistic initial conditions -
Following the Trails of Light in Curved Spacetime
Following the trails of light in curved spacetime by Darius Bunandar THESIS Presented in Partial Fulfillment of the Requirements for the Degree of Bachelor of Science in Physics The University of Texas at Austin Austin, Texas May 2013 The Thesis Committee for Darius Bunandar certifies that this is the approved version of the following thesis: Following the trails of light in curved spacetime Committee: Richard A. Matzner, Supervisor Philip J. Morrison Greg O. Sitz © 2013 - D B A . Following the trails of light in curved spacetime Darius Bunandar The University of Texas at Austin, 2013 Supervisor: Richard A. Matzner Light has played an instrumental role in the initial development of the theory of relativity. In this thesis, we intend to explore other physical phe- nomena that can be explained by tracing the path that light takes in curved spacetime. We consider the null geodesic and eikonal equations that are equivalent descriptions of the propagation of light rays within the frame- work of numerical relativity. We find that they are suited for different phys- ical situations. The null geodesic equation is more suited for tracing the path of individual light rays. We solve this equation in order to visualize images of the sky that have been severely distorted by one or more black holes, the so-called gravitational lensing effect. We demonstrate that our procedure of solving the null geodesic equation is sufficiently robust to produce some of the world’s first images of the lensing effect from fully dynamical binary black hole coalescence. The second formulation of propagation of light that we explore is the eikonal surface equation. -
Trumpet Initial Data for Highly Boosted Black Holes and High Energy Binaries
TRUMPET INITIAL DATA FOR HIGHLY BOOSTED BLACK HOLES AND HIGH ENERGY BINARIES Kyle Patrick Slinker A dissertation submitted to the faculty at the University of North Carolina at Chapel Hill in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Physics and Astronomy. Chapel Hill 2017 Approved by: Charles R. Evans J. Christopher Clemens Louise A. Dolan Joaqu´ınE. Drut Fabian Heitsch Reyco Henning c 2017 Kyle Patrick Slinker ALL RIGHTS RESERVED ii ABSTRACT Kyle Patrick Slinker: Trumpet Initial Data for Highly Boosted Black Holes and High Energy Binaries (Under the direction of Charles R. Evans) Initial data for a single boosted black hole is constructed that analytically contains no initial transient (junk) gravitational radiation and is adapted to the moving punctures gauge conditions. The properties of this data are investigated in detail. It is found to be generally superior to canonical Bowen-York data and, when implemented numerically in simulations, yields orders of magnitude less junk gravitational radiation content and more accurate black hole velocities. This allows for modeling of black holes that are boosted faster than previously possible. An approximate superposition of the data is used to demonstrate how a binary black hole system can be constructed to retain the advantages found for the single black hole. Extensions to black holes with spin are considered. iii TABLE OF CONTENTS LIST OF TABLES ............................................. vii LIST OF FIGURES ............................................ viii LIST OF ABBREVIATIONS AND SYMBOLS ........................... xii 1 Introduction ............................................... 1 1.1 Testing General Relativity Through Gravitational Wave Astronomy . 1 1.2 Numerical Relativity . 2 1.3 Project Goals . -
High-Stakes Standardized Testing in Nigeria and the Erosion of a Critical African Worldview
HIGH-STAKES STANDARDIZED TESTING IN NIGERIA AND THE EROSION OF A CRITICAL AFRICAN WORLDVIEW by Ijeoma Ekoh A thesis submitted in conformity with the requirements for the degree of Master of Arts Graduate Department of Humanities, Social Sciences and Social Justice Education Ontario Institute for Studies in Education University of Toronto © Copyright by Ijeoma Ekoh 2012 HIGH-STAKES STANDARDIZED TESTING IN NIGERIA AND THE EROSION OF A CRITICAL AFRICAN WORLDVIEW Masters of Arts 2012 Ijeoma Ekoh Graduate Department of Humanities, Social Sciences and Social Justice Education University of Toronto Abstract This thesis investigates the practice of high-stakes standardized testing in Nigeria. Examining its colonial histories, its philosophical incongruities with African indigenous education, and its neocolonial foundations, it argues that high-stakes testing in Nigeria facilitates the erosion of a critical African worldview. It demonstrates that through high- stakes testing’s reproduction of social and regional inequalities, the unethicality of its systems and practices as well as its exemplification of Freire’s concept of normative and non liberatory education as the “practice of domination”; high-stakes standardized testing in Nigeria seamlessly fits into the neo-colonial and neoliberal logic of education as a site of psychological colonization and the material exploitation of the people by the ruling elite. ii Acknowledgements Ajamu. You serve as a daily reminder that ideology must be lived, and that theorizing must be accompanied with concrete political action. Your conviction that there can, and must be, a better tomorrow for African peoples and your daily activism to make that possible inspires me. Ifunanya and Ikenna Ekoh. -
There Is No Special Condition Where a Velocity of a Light Wave Is Invariance in All Inertial Frames
There is no special condition where a velocity of a light wave is invariance in all inertial frames. Mahesh Gupta ( [email protected] ) Madurai Kamaraj University https://orcid.org/0000-0002-1772-8490 Prafful Acharya Amrita Vishwa Vidyapeetham University Rampravesh Yadav University of Mumbai Article Keywords: Frame of Reference, The Time, Newton’s Law of motion, Galilean Transformation, Linear Motion, Periodic Motion, Particle-Wave Duality of Light, Lorentz Transformation, Special Theory of Relativity Posted Date: January 15th, 2021 DOI: https://doi.org/10.21203/rs.3.rs-143936/v2 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License There is no special condition where a velocity of a light wave is invariance in all inertial frames. Mahesh Gupta, Prafful Acharya & Rampravesh R. Yadav [email protected] Mumbai, Maharashtra, India Abstract: This study of the literature reveals that the concept such as the velocity of a light wave is invariance in all inertial frames is wrong. A velocity of any motion always depends upon its reference frame. There is no special condition present in nature where the velocity is invariance in all inertial frames. Galileo Galilei defined speed is the distance covered per unit of time. Sir Isaac Newton defined velocity is the speed with direction. In the same period, physicists introduced the concept such as wavelength and frequency for measuring the speed a wave. The wave motion in which cycles are repeating after the same interval of time with the same distance between them. In 1887, Albert A. Michelson and Edward W. -
Mathematics of General Relativity - Wikipedia, the Free Encyclopedia Page 1 of 11
Mathematics of general relativity - Wikipedia, the free encyclopedia Page 1 of 11 Mathematics of general relativity From Wikipedia, the free encyclopedia The mathematics of general relativity refers to various mathematical structures and General relativity techniques that are used in studying and formulating Albert Einstein's theory of general Introduction relativity. The main tools used in this geometrical theory of gravitation are tensor fields Mathematical formulation defined on a Lorentzian manifold representing spacetime. This article is a general description of the mathematics of general relativity. Resources Fundamental concepts Note: General relativity articles using tensors will use the abstract index Special relativity notation . Equivalence principle World line · Riemannian Contents geometry Phenomena 1 Why tensors? 2 Spacetime as a manifold Kepler problem · Lenses · 2.1 Local versus global structure Waves 3 Tensors in GR Frame-dragging · Geodetic 3.1 Symmetric and antisymmetric tensors effect 3.2 The metric tensor Event horizon · Singularity 3.3 Invariants Black hole 3.4 Tensor classifications Equations 4 Tensor fields in GR 5 Tensorial derivatives Linearized Gravity 5.1 Affine connections Post-Newtonian formalism 5.2 The covariant derivative Einstein field equations 5.3 The Lie derivative Friedmann equations 6 The Riemann curvature tensor ADM formalism 7 The energy-momentum tensor BSSN formalism 7.1 Energy conservation Advanced theories 8 The Einstein field equations 9 The geodesic equations Kaluza–Klein -
The Reissner-Nordström Metric
The Reissner-Nordström metric Jonatan Nordebo March 16, 2016 Abstract A brief review of special and general relativity including some classi- cal electrodynamics is given. We then present a detailed derivation of the Reissner-Nordström metric. The derivation is done by solving the Einstein-Maxwell equations for a spherically symmetric electrically charged body. The physics of this spacetime is then studied. This includes gravitational time dilation and redshift, equations of motion for both massive and massless non-charged particles derived from the geodesic equation and equations of motion for a massive charged par- ticle derived with lagrangian formalism. Finally, a quick discussion of the properties of a Reissner-Nordström black hole is given. 1 Contents 1 Introduction 3 2 Review of Special Relativity 3 2.1 4-vectors . 6 2.2 Electrodynamics in Special Relativity . 8 3 Tensor Fields and Manifolds 11 3.1 Covariant Differentiation and Christoffel Symbols . 13 3.2 Riemann Tensor . 15 3.3 Parallel Transport and Geodesics . 18 4 Basics of General Relativity 19 4.1 The Equivalence Principle . 19 4.2 The Principle of General Covariance . 20 4.3 Electrodynamics in General Relativity . 21 4.4 Newtonian Limit of the Geodesic Equation . 22 4.5 Einstein’s Field Equations . 24 5 The Reissner-Nordström Metric 25 5.1 Gravitational Time Dilation and Redshift . 32 5.2 The Geodesic Equation . 34 5.2.1 Comparison to Newtonian Mechanics . 37 5.2.2 Circular Orbits of Photons . 38 5.3 Motion of a Charged Particle . 38 5.4 Event Horizons and Black Holes . 40 6 Summary and Conclusion 44 2 1 Introduction In 1915 Einstein completed his general theory of relativity. -
Dawn of Fluid Dynamics : a Discipline Between Science And
Titelei Eckert 11.04.2007 14:04 Uhr Seite 3 Michael Eckert The Dawn of Fluid Dynamics A Discipline between Science and Technology WILEY-VCH Verlag GmbH & Co. KGaA Titelei Eckert 11.04.2007 14:04 Uhr Seite 1 Michael Eckert The Dawn of Fluid Dynamics A Discipline between Science and Technology Titelei Eckert 11.04.2007 14:04 Uhr Seite 2 Related Titles R. Ansorge Mathematical Models of Fluiddynamics Modelling, Theory, Basic Numerical Facts - An Introduction 187 pages with 30 figures 2003 Hardcover ISBN 3-527-40397-3 J. Renn (ed.) Albert Einstein - Chief Engineer of the Universe 100 Authors for Einstein. Essays approx. 480 pages 2005 Hardcover ISBN 3-527-40574-7 D. Brian Einstein - A Life 526 pages 1996 Softcover ISBN 0-471-19362-3 Titelei Eckert 11.04.2007 14:04 Uhr Seite 3 Michael Eckert The Dawn of Fluid Dynamics A Discipline between Science and Technology WILEY-VCH Verlag GmbH & Co. KGaA Titelei Eckert 11.04.2007 14:04 Uhr Seite 4 The author of this book All books published by Wiley-VCH are carefully produced. Nevertheless, authors, editors, and Dr. Michael Eckert publisher do not warrant the information Deutsches Museum München contained in these books, including this book, to email: [email protected] be free of errors. Readers are advised to keep in mind that statements, data, illustrations, proce- Cover illustration dural details or other items may inadvertently be “Wake downstream of a thin plate soaked in a inaccurate. water flow” by Henri Werlé, with kind permission from ONERA, http://www.onera.fr Library of Congress Card No.: applied for British Library Cataloging-in-Publication Data: A catalogue record for this book is available from the British Library. -
Conformal Field Theory and Black Hole Physics
CONFORMAL FIELD THEORY AND BLACK HOLE PHYSICS Steve Sidhu Bachelor of Science, University of Northern British Columbia, 2009 A Thesis Submitted to the School of Graduate Studies of the University of Lethbridge in Partial Fulfilment of the Requirements for the Degree MASTER OF SCIENCE Department of Physics and Astronomy University of Lethbridge LETHBRIDGE, ALBERTA, CANADA c Steve Sidhu, 2012 Dedication To my parents, my sister, and Paige R. Ryan. iii Abstract This thesis reviews the use of 2-dimensional conformal field theory applied to gravity, specifically calculating Bekenstein-Hawking entropy of black holes in (2+1) dimen- sions. A brief review of general relativity, Conformal Field Theory, energy extraction from black holes, and black hole thermodynamics will be given. The Cardy formula, which calculates the entropy of a black hole from the AdS/CFT duality, will be shown to calculate the correct Bekenstein-Hawking entropy of the static and rotating BTZ black holes. The first law of black hole thermodynamics of the static, rotating, and charged-rotating BTZ black holes will be verified. iv Acknowledgements I would like to thank my supervisors Mark Walton and Saurya Das. I would also like to thank Ali Nassar and Ahmed Farag Ali for the many discussions, the Theo- retical Physics Group, and the entire Department of Physics and Astronomy at the University of Lethbridge. v Table of Contents Approval/Signature Page ii Dedication iii Abstract iv Acknowledgements v Table of Contents vi 1 Introduction 1 2 Einstein’s field equations and black hole solutions 7 2.1 Conventions and notations . 7 2.2 Einstein’s field equations .