Cosmology, Relativity, and Gravity Commons^™

Properties Of Slicing Conditions For Charged Black Holes, Sean E. Li

Honors Projects

We consider an earlier analysis by Baumgarte and de Oliveira (2022) of static Bona-Massó slices of stationary, nonrotating, uncharged black holes, represented by Schwarzschild spacetimes, and generalize that approach to Reissner-Nordström (RN) spacetimes, representing stationary, nonrotating black holes that carry a nonzero charge. This charge is parametrized by the charge-to-mass ratio λ ≡ Q/M, where M is the black-hole mass and the charge Q may represent electrical charge or act as a placeholder for extensions of general relativity. We use a height-function approach to construct time-independent, spherically symmetric slices that satisfy a so-called Bona-Massó slicing condition. We …

Using Numerical Relativity To Explore Strong Gravity And Develop Force-Free Electrodynamics Simulation Software With Best-Practice Development, Patrick E. Nelson

Graduate Theses, Dissertations, and Problem Reports

In this dissertation, we explore the effects of extremely strong gravitational and electro- dynamic fields using the techniques of numerical relativity. We use the existing black hole simulation software in the Einstein Toolkit to compute the spin-up of two initially nonspin- ning black holes as they pass by each other in space. The angular momentum is imparted by the tidal interaction between the two black holes, in a parallel to Earth’s tides, as described by classical mechanics, which also transfer angular momentum between the Earth’s rotation and the Moon’s orbit. The largest observed dimensionless spin observed was 0.20 with an …

Measurements And Mitigation Of Scattered Light Noise In Ligo, Corey Daniel Austin

LSU Doctoral Dissertations

The Advanced LIGO (aLIGO) detectors use 1064 nm lasers to measure the tiny fluctuations in spacetime that occur when gravitational waves pass through the earth. LIGO makes use of advanced coating methods and materials to limit the amount of light that scatters from the main beam, but some amount of light does scatter. This stray light can interact with surfaces inside the interferometer that are not seismically isolated and then recombine with the main beam, introducing excess noise into the gravitational wave channel. This thesis reviews the methods for modeling scattered light with ray tracing software and analytical models, for …

Stability Of Regular Thin Shell Wormholes Supported By Vdw Quintessence, A. Eid

Applications and Applied Mathematics: An International Journal (AAM)

The dynamical equations of motion for a thin shell wormhole from regular black holes that are supported by Van der Waals (VDW) quintessence equation of state (EoS) are constructed, through cut and -paste technique. The linearized stability of regular wormhole is derived. The presences of unstable and stable static solutions with different value of some parameters are analyzed.

What Do We Know About Lorentz Symmetry?, Q. G. Bailey

Quentin Bailey

Precision tests of Lorentz symmetry have become increasingly of interest to the broader gravitational and high-energy physics communities. In this talk, recent work on violations of local Lorentz invariance in gravity is discussed, including recent analysis constraining Lorentz violation in a variety of gravitational tests. The arena of short-range tests of gravity is highlighted, demonstrating that such tests are sensitive to a broad class of unexplored signals that depend on sidereal time and the geometry of the experiment.

Location, Orbit And Energy Of A Meteoroid Impacting The Moon During The Lunar Eclipse Of January 21, 2019 & Testing The Weak Equivalence Principle With Cosmological Gamma Ray Bursts, Matipon Tangmatitham

Dissertations, Master's Theses and Master's Reports

Location, orbit and energy of a meteoroid impacting the moon during the Lunar Eclipse of January 21, 2019

During the total lunar eclipse of January 21, 2019 at least two meteoroids impacted the moon producing visible flash lights on the near side. One of the impacts occurred on the darkest side of the visible lunar face and was witnessed by many astrophotographers. In this paper we present estimations of the location, impact parameters (velocity and incoming direction), orbit and energy of the meteoroid, as obtained from images and videos collected by amateur astronomers in Colombia, the Dominican Republic, Morocco, USA, …

Consistent Young Earth Relativistic Cosmology, Phillip W. Dennis

Proceedings of the International Conference on Creationism

We present a young earth creationist (YEC) model of creation that is consistent with distant light from distant objects in the cosmos. We discuss the reality of time from theological/philosophical foundations. This results in the rejection of the idealist viewpoint of relativity and the recognition of the reality of the flow of time and the existence of a single cosmological “now.” We begin the construction of the YEC cosmology with an examination of the “chronological enigmas” of the inhomogeneous solutions of the Einstein field equations (EFE) of General Relativity (GR). For this analysis we construct an inhomogeneous model by way …

Does The Black Hole Shadow Probe The Event Horizon Geometry?, Pedro V. P. Cunha, Carlos A. R. Herdeiro, Maria J. Rodriguez

All Physics Faculty Publications

There is an exciting prospect of obtaining the shadow of astrophysical black holes (BHs) in the near future with the Event Horizon Telescope. As a matter of principle, this justifies asking how much one can learn about the BH horizon itself from such a measurement. Since the shadow is determined by a set of special photon orbits, rather than horizon properties, it is possible that different horizon geometries yield similar shadows. One may then ask how sensitive is the shadow to details of the horizon geometry? As a case study, we consider the double Schwarzschild BH and analyze the impact …

Gw170104: Observation Of A 50-Solar-Mass Binary Black Hole Coalescence At Redshift 0.2, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, B. Hughey, J. W. W. Pratt, E. Schmidt, G. Schwalbe, M. J. Szczepańczyk, M. Zanolin, Et Al.

Publications

We describe the observation of GW170104, a gravitational-wave signal produced by the coalescence of a pair of stellar-mass black holes. The signal was measured on January 4, 2017 at 10∶11:58.6 UTC by the twin advanced detectors of the Laser Interferometer Gravitational-Wave Observatory during their second observing run, with a network signal-to-noise ratio of 13 and a false alarm rate less than 1 in 70 000 years. The inferred component black hole masses are 31.2 þ8.4 −6.0M⊙ and 19.4 þ5.3 −5.9M⊙ (at the 90% credible level). The black hole spins are best constrained through measurement of the effective inspiral spin parameter, …

Gravitational Wave Behavior At A Vacuum-Matter Interface, Jake Litterer

Honors Program Theses

In classical electrodynamics, boundary conditions of the E and B fields are derived from Maxwell's equations, which are used to derive the Fresnel equations describing the behavior of a wave at an interface between media with given indices of refraction. Though electrodynamics and gravity are in some instances strikingly analogous, boundary conditions in general relativity are somewhat more opaque. We will see that while while continuity of the metric must be true in general, discontinuity of the extrinsic curvature of spacetime, while allowed by the Einstein field equations, results in a singularity in the energy-momentum tensor. This singularity is interpreted …

The Basic Physics Of The Binary Black Hole Merger Gw150914, B. P. Abbott, K. Gill, B. Hughey, J. Pratt, M. J. Szczepańczyk, M. Zanolin, Et Al.

Publications

The first direct gravitational-wave detection was made by the Advanced Laser Interferometer Gravitational Wave Observatory on September 14, 2015. The GW150914 signal was strong enough to be apparent, without using any waveform model, in the filtered detector strain data. Here, features of the signal visible in the data are analyzed using concepts from Newtonian physics and general relativity, accessible to anyone with a general physics background. The simple analysis presented here is consistent with the fully general-relativistic analyses published elsewhere, in showing that the signal was produced by the inspiral and subsequent merger of two black holes. The black holes …

Directly Comparing Gw150914 With Numerical Solutions Of Einstein's Equations For Binary Black Hole Coalescence, B. P. Abbott, K. Gill, B. Hughey, M. J. Szczepańczyk, M. Zanolin, Et Al.

Publications

We compare GW150914 directly to simulations of coalescing binary black holes in full general relativity, including several performed specifically to reproduce this event. Our calculations go beyond existing semianalytic models, because for all simulations—including sources with two independent, precessing spins—we perform comparisons which account for all the spin-weighted quadrupolar modes, and separately which account for all the quadrupolar and octopolar modes. Consistent with the posterior distributions reported by Abbott et al. [Phys. Rev. Lett. 116, 241102 (2016)] (at the 90% credible level), we find the data are compatible with a wide range of nonprecessing and precessing simulations. Follow-up simulations performed …

Topics In The Detection Of Gravitational Waves From Compact Binary Inspirals, Shasvath Jagat Kapadia

Graduate Theses and Dissertations

Orbiting compact binaries - such as binary black holes, binary neutron stars and neutron star-black hole binaries - are among the most promising sources of gravitational waves observable by ground-based interferometric detectors. Despite numerous sophisticated engineering techniques, the gravitational wave signals will be buried deep within noise generated by various instrumental and environmental processes, and need to be extracted via a signal processing technique referred to as matched filtering.

Matched filtering requires large banks of signal templates that are faithful representations of the true gravitational waveforms produced by astrophysical binaries. The accurate and efficient production of templates is thus crucial …

The Geometry Of Spacetime And Its Singular Nature, Filip Dul

Honors Scholar Theses

One hundred years ago, Albert Einstein revolutionized our understanding of gravity, and thus the large-scale structure of spacetime, by implementing differential geometry as the pri- mary medium of its description, thereby condensing the relationship between mass, energy and curvature of spacetime manifolds with the Einstein field equations (EFE), the primary compo- nent of his theory of General Relativity. In this paper, we use the language of Semi-Riemannian Geometry to examine the Schwarzschild and the Friedmann-Lemaˆıtre-Robertson-Walker met- rics, which represent some of the most well-known solutions to the EFE. Our investigation of these metrics will lead us to the problem of …

Exact Solutions In Gravity: A Journey Through Spacetime With The Kerr-Schild Ansatz, Benjamin Ett

Doctoral Dissertations

The Kerr-Schild metric ansatz can be expressed in the form $g_{ab} = \gbar_{ab}+\lambda k_ak_b$, where $\gbar_{ab}$ is a background metric satisfying Einstein's equations, $k_a$ is a null-vector, and $\lambda$ is a free parameter. It was discovered in 1963 while searching for the elusive rotating black hole solutions to Einstein's equations, fifty years after the static solution was found and Einstein first formulated his theory of general relativity. While the ansatz has proved an excellent tool in the search for new exact solutions since then, its scope is limited, particularly with respect to higher dimensional theories. In this thesis, we present …

What Do We Know About Lorentz Symmetry?, Q. G. Bailey

Publications

Precision tests of Lorentz symmetry have become increasingly of interest to the broader gravitational and high-energy physics communities. In this talk, recent work on violations of local Lorentz invariance in gravity is discussed, including recent analysis constraining Lorentz violation in a variety of gravitational tests. The arena of short-range tests of gravity is highlighted, demonstrating that such tests are sensitive to a broad class of unexplored signals that depend on sidereal time and the geometry of the experiment.

Quantum Tests Of The Einstein Equivalence Principle With The Ste-Quest Space Mission, Brett Altschul, Quentin G. Bailey, Luc Blanchet, Kai Bongs, Philippe Bouyer, Luigi Cacciapuoti, Et Al.

Publications

We present in detail the scientific objectives in fundamental physics of the Space–Time Explorer and QUantum Equivalence Space Test (STE–QUEST) space mission. STE–QUEST was pre-selected by the European Space Agency together with four other missions for the cosmic vision M3 launch opportunity planned around 2024. It carries out tests of different aspects of the Einstein Equivalence Principle using atomic clocks, matter wave interferometry and long distance time/frequency links, providing fascinating science at the interface between quantum mechanics and gravitation that cannot be achieved, at that level of precision, in ground experiments. We especially emphasize the specific strong interest of performing …

Spectral Distortion In A Radially Inhomogeneous Cosmology, R. R. Caldwell, N. A. Maksimova

Dartmouth Scholarship

The spectral distortion of the cosmic microwave background blackbody spectrum in a radially inhomogeneous space-time, designed to exactly reproduce a ΛCDM expansion history along the past light cone, is shown to exceed the upper bound established by COBE-FIRAS by a factor of approximately 3700. This simple observational test helps uncover a slew of pathological features that lie hidden inside the past light cone, including a radially contracting phase at decoupling and, if followed to its logical extreme, a naked singularity at the radially inhomogeneous big bang.

Unsolved Problems In Special And General Relativity, Florentin Smarandache, Fu Yuhua, Zhao Fengjuan

Branch Mathematics and Statistics Faculty and Staff Publications

This book includes 21 papers written by 23 authors and co-authors. All papers included herein are produced by scholars from People’s Republic of China, except two papers written by Prof. L. Sapogin, V. A. Dzhanibekov, Yu. A. Ryabov from Russia, and by Prof. Florentin Smarandache from USA. The editors hope that all these papers will contribute to the advance of scholarly research on several aspects of Special and General Relativity. This book is suitable for students and scholars interested in studies on physics. The first paper is written by Hua Di. He writes that Einstein’s general theory of relativity cannot …

Exploring The Possibility Of Floating Orbits For Extreme Mass Ratio Binary Black Holes, Shasvath Jagat Kapadia

Graduate Theses and Dissertations

A binary black hole system, where each black hole orbits the system's center of mass, loses energy by emission of gravitational waves. This causes both black holes to spiral in towards each other. However, if the binary were to, by some mechanism, gain orbital energy at the same rate that it radiates away this energy, a non-decaying or “floating” orbit would result. The thesis uses superradiant scattering and tidal friction, which are two equivalent ways of looking at a process by which the system can gain orbital energy from the spin energy of either black hole, to determine the possibility …

Isometries And Spontaneous Lorentz Violation In General Relativity, Greg Merritt

Honors Theses

General Relativity, or GR, is a theory which describes gravity as a manifestation of the curvature of space and time. While the other three fundamental forces in nature are represented as field theories, GR is a geometric theory. In the search for a way to reconcile the field theories for the electromagnetic, strong, and weak forces with the gravitational force, a logical place to start is by re-expressing GR as a field theory. In doing so, we find that the theory contains a number of symmetries. When we solve the equations in GR, we find that by choosing certain solutions …

An Analytical And Numerical Treatment Of Inclined Elliptical Orbits About A Kerr Black Hole, Peter G. Komorowski

Electronic Thesis and Dissertation Repository

Since its publication in 1915, Einstein's theory of general relativity has yielded significant results; they include: analytical solutions to the Einstein field equations; improved analysis of orbital dynamics; and the prediction of gravitational wave (GW) radiation. Gravitation is the weakest of the fundamental interactions; and theoretical models of GW generation and propagation show that its detection poses a significant technical challenge. Unlike the study of electromagnetic radiation, experiments within the laboratory are virtually impossible; so astronomical sources of GW, such as binary black hole systems, offer an alternative. But GW detection remains difficult. The matched filtering techniques used to discriminate …

A Mathematical Exploration Of Low-Dimensional Black Holes, Abigail Lauren Stevens

Senior Projects Spring 2011

In this paper we will be mathematically exploring low-dimensional gravitational physics and, more specifically, what it tells us about low-dimensional black holes and if there exists a Schwarzschild solution to Einstein's field equation in 2+1 dimensions. We will be starting with an existing solution in 3+1 dimensions, and then reconstructing the classical and relativistic arguments for 2+1 dimensions. Our conclusion is that in 2+1 dimensions, the Schwarzschild solution to Einstein's field equation is non-singular, and therefore it does not yield a black hole. While we still arrive at conic orbits, the relationship between Minkowski-like and Newtonian forces, energies, and geodesics …

Exotic Smoothness In Four Dimensions And Euclidean Quantum Gravity, Christopher L. Duston

Physics Faculty Publications

In this paper we calculate the effect of the inclusion of exotic smooth structures on typical observables in Euclidean quantum gravity. We do this in the semiclassical regime for several gravitational free-field actions and find that the results are similar, independent of the particular action that is chosen. These are the first results of their kind in dimension four, which we extend to include one-loop contributions as well. We find these topological features can have physically significant results without the need for additional exotic physics.

Signals For Lorentz Violation In Post-Newtonian Gravity, Quentin G. Bailey, V. Alan Kostelecký

Publications

The pure-gravity sector of the minimal standard-model extension is studied in the limit of Riemann spacetime. A method is developed to extract the modified Einstein field equations in the limit of small metric fluctuations about the Minkowski vacuum, while allowing for the dynamics of the 20 independent coefficients for Lorentz violation. The linearized effective equations are solved to obtain the post-Newtonian metric. The corresponding post-Newtonian behavior of a perfect fluid is studied and applied to the gravitating many-body system. Illustrative examples of the methodology are provided using bumblebee models. The implications of the general theoretical results are studied for a …

Neutrosophic Methods In General Relativity, Florentin Smarandache, Dmitri Rabounski, Larissa Borissova

Branch Mathematics and Statistics Faculty and Staff Publications

In this work the authors apply concepts of Neutrosophic Logic to the General Theory of Relativity to obtain a generalisation of Einstein’s fourdimensional pseudo-Riemannian differentiable manifold in terms of Smarandache Geometry (Smarandache manifolds), by which new classes of relativistic particles and non-quantum teleportation are developed. Fundamental features of Neutrosophic Logic are its denial of the Law of Excluded Middle, and open (or estimated) levels of truth, falsity and indeterminancy. Both Neutrosophic Logic and Smarandache Geometry were invented some years ago by one of the authors (F. Smarandache). The application of these purely mathematical theories to General Relativity reveals hitherto unknown …

Black Holes And Singularities, Andrew Lang

College of Science and Engineering Faculty Research and Scholarship

First, I give definitions and mathematical preliminaries. Secondly, I give a history of the derivation of Einstein's field equations. From this basis, I present a derivation of Schwarzschild's solution. A discussion then follows of various types of black holes: stationary, charged, rotating, and charged/rotating. I also give a pictorial representation of the properties of each algebraically special solution. Finally, I present a general definition of singularities along with a discussion of closed trapped surfaces and naked singularities.