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Full-Text Articles in Physical Sciences and Mathematics
Find The Distance To The Moon, Dean Smith
Find The Distance To The Moon, Dean Smith
AI Assignment Library
This assignment leads students through a series of measurements that lead the student to calculate the distance to the Moon. Students who complete this assignment will see how knowledge that they would normally look up is gathered through experiment and observation.
Perturbative Unitarity And Nec Violation In Genesis Cosmology, Yong Cai, Ji Xu, Shuai Zhao, Siyi Zhou
Perturbative Unitarity And Nec Violation In Genesis Cosmology, Yong Cai, Ji Xu, Shuai Zhao, Siyi Zhou
Physics Faculty Publications
Explorations of the violation of null energy condition (NEC) in cosmology could enrich our understanding of the very early universe and the related gravity theories. Although a fully stable NEC violation can be realized in the “beyond Horndeski” theory, it remains an open question whether a violation of the NEC is allowed by some fundamental properties of UV-complete theories or the consistency requirements of effective field theory (EFT). We investigate the tree-level perturbative unitarity for stable NEC violations in the contexts of both Galileon and “beyond Horndeski” genesis cosmology, in which the universe is asymptotically Minkowskian in the past. We …
A Complete Analytic Gravitational Wave Model For Undergraduates, Dillon Buskirk, Maria Babiuc-Hamilton
A Complete Analytic Gravitational Wave Model For Undergraduates, Dillon Buskirk, Maria Babiuc-Hamilton
Physics Faculty Research
Gravitational waves are produced by orbiting massive binary objects, such as black holes and neutron stars, and propagate as ripples in the very fabric of space-time. As the waves carry off orbital energy, the two bodies spiral into each other and eventually merge. They are described by Einstein's equations of general relativity. For the early phase of the orbit, called the inspiral, Einstein equations can be linearised and solved through analytical approximations, while for the late phase, near the merger, we need to solve the fully nonlinear Einstein's equations on supercomputers. In order to recover the gravitational wave for the …
Gravity's Light In The Shadow Of The Moon, Andri Gretarsson, Preston Jones, Douglas Singleton
Gravity's Light In The Shadow Of The Moon, Andri Gretarsson, Preston Jones, Douglas Singleton
Publications
In this essay we look at the possibility of vacuum production of very low frequency electromagnetic radiation from a gravitational wave background (i.e. gravity's light). We also propose that this counterpart electromagnetic radiation should be detectable by a lunar orbiting satellite which is periodically occulted by the Moon (i.e., in the shadow of the Moon). For concreteness we consider the possibility of detection of both the gravitational wave and hypothesized electromagnetic radiation counterpart from the supernova core collapse of Betelgeuse
Relating Noncommutative So(2,3)* Gravity To The Lorentz-Violating Standard-Model Extension, Quentin G. Bailey, Charles D. Lane
Relating Noncommutative So(2,3)* Gravity To The Lorentz-Violating Standard-Model Extension, Quentin G. Bailey, Charles D. Lane
Publications
We consider a model of noncommutative gravity that is based on a spacetime with broken local SO(2,3)* symmetry. We show that the torsion-free version of this model is contained within the framework of the Lorentz-violating Standard-Model Extension (SME). We analyze in detail the relation between the torsion-free, quadratic limits of the broken SO(2,3)* model and the Standard-Model Extension. As part of the analysis, we construct the relevant geometric quantities to quadratic order in the metric perturbation around a flat background.
Gravity Then And Now, Paul Ingraham
Gravity Then And Now, Paul Ingraham
Student Writing
This paper discusses the theory of gravity from the time it was discovered by Sir Isaac Newton to present time with the discovery of gravitational waves by Albert Einstein, and the detection of gravitational waves. Stephen Hawking's and Leonard Mlodinow's recent book, The Grand Design, provides support for Edward Witten's M-theory. Gravity was the first of the four fundamental forces to be discovered, and that last to be detected. Einstein proposed that gravity was not only a force, but also could be characterized as a wave on the space-time continuum.
Gw170817: Implications For The Stochastic Gravitational-Wave Background From Compact Binary Coalescences, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, E. M. Gretarsson, B. Hughey, M. Muratore, J. W. W. Pratt, S. G. Schwalbe, K. Staats, M. J. Szczepańczyk, M. Zanolin, Et Al.
Gw170817: Implications For The Stochastic Gravitational-Wave Background From Compact Binary Coalescences, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, E. M. Gretarsson, B. Hughey, M. Muratore, J. W. W. Pratt, S. G. Schwalbe, K. Staats, M. J. Szczepańczyk, M. Zanolin, Et Al.
Publications
The LIGO Scientific and Virgo Collaborations have announced the event GW170817, the first detection of gravitational waves from the coalescence of two neutron stars. The merger rate of binary neutron stars estimated from this event suggests that distant, unresolvable binary neutron stars create a significant astrophysical stochastic gravitational-wave background. The binary neutron star component will add to the contribution from binary black holes, increasing the amplitude of the total astrophysical background relative to previous expectations. In the Advanced LIGO-Virgo frequency band most sensitive to stochastic backgrounds (near 25 Hz), we predict a total astrophysical background with amplitude ΩGW(f=25 Hz)=1.8+2.7−1.3×10−9 with …
Investigating The Opal Cubesat’S Ability To Measure Thermospheric Gravity Waves, Kenneth Zia, Michael J. Taylor, Ludger Scherliess
Investigating The Opal Cubesat’S Ability To Measure Thermospheric Gravity Waves, Kenneth Zia, Michael J. Taylor, Ludger Scherliess
Posters
Understanding the Earth’s lower thermosphere is of high interest to the space science community because of competing forcing due to solar heating above and episodic wave forcing from below. The NSF sponsored OPAL cubesat is designed to measure the temperature profile in this region by observing day-time O2 A time O2 A-band (~760nm) emission on the limb and is expected to be launched from the ISS (International Space Station). To band (~760nm) emission on the limb and is expected to be launched from the ISS (International Space Station). To investigate the instrument’s ability to detect space weather signatures (i.e. solar …
A Gravitational-Wave Standard Siren Measurement Of The Hubble Constant, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, E. M. Gretarrson, B. Hughey, M. Muratore, J. W. W. Pratt, S. G. Schwalde, K. Staats, M. J. Szczepańczyk, M. Zanolin, Et Al.
A Gravitational-Wave Standard Siren Measurement Of The Hubble Constant, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, E. M. Gretarrson, B. Hughey, M. Muratore, J. W. W. Pratt, S. G. Schwalde, K. Staats, M. J. Szczepańczyk, M. Zanolin, Et Al.
Publications
The detection of GW170817 (Abbott et al. 2017a) in both gravitational waves and electromagnetic waves heralds the age of gravitational-wave multi-messenger astronomy. On 17 August 2017 the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) (LIGO Scientific Collaboration et al. 2015) and Virgo (Acernese et al. 2015) detectors observed GW170817, a strong signal from the merger of a binary neutron-star system. Less than 2 seconds after the merger, a gamma-ray burst (GRB 170817A) was detected within a region of the sky consistent with the LIGO-Virgo-derived location of the gravitational-wave source (Abbott et al. 2017b; Goldstein et al. 2017; Savchenko et al. 2017). …
Constraints On Sme Coefficients From Lunar Laser Ranging, Very Long Baseline Interferometry, And Asteroid Orbital Dynamics, C. Le Poncin-Lafitte, A. Bourgoin, A. Hees, S. Bouquillon, S. Lambert, Q. G. Bailey, Et Al.
Constraints On Sme Coefficients From Lunar Laser Ranging, Very Long Baseline Interferometry, And Asteroid Orbital Dynamics, C. Le Poncin-Lafitte, A. Bourgoin, A. Hees, S. Bouquillon, S. Lambert, Q. G. Bailey, Et Al.
Publications
Lorentz symmetry violations can be parametrized by an effective field theory framework that contains both General Relativity and the Standard Model of particle physics, called the Standard-Model Extension or SME. We consider in this work only the pure gravitational sector of the minimal SME. We present new constraints on the SME coefficients obtained from lunar laser ranging, very long baseline interferometry, and planetary motions.
Gravity Sector Of The Sme, Q. G. Bailey
Gravity Sector Of The Sme, Q. G. Bailey
Publications
In this talk, the gravity sector of the effective field theory description of local Lorentz violation is discussed, including minimal and nonminimal curvature couplings. Also, recent experimental and observational analyses including solar-system ephemeris and short-range gravity tests are reviewed.
Schwarzschild Spacetime And Friedmann-Lemaitre-Robertson-Walker Cosmology, Zachary Cohen
Schwarzschild Spacetime And Friedmann-Lemaitre-Robertson-Walker Cosmology, Zachary Cohen
Honors Scholar Theses
The advent of General Relativity via Einstein's field equations revolutionized our understanding of gravity in our solar system and universe. The idea of General Relativity posits that gravity is entirely due to the geometry of the universe -- that is, the mass distribution throughout the universe results in the ``curving" of spacetime, which gives us the physics we see on a large scale. In the framework of General Relativity, we find that the universe behaves differently than was predicted in the model of gravitation developed by Newton. We will derive the general relativistic model for a simple system near a …
Schwarzschild Spacetime And Friedmann-Lemaitre-Robertson-Walker Cosmology, Zachary Cohen
Schwarzschild Spacetime And Friedmann-Lemaitre-Robertson-Walker Cosmology, Zachary Cohen
Honors Scholar Theses
The advent of General Relativity via Einstein's field equations revolutionized our understanding of gravity in our solar system and universe. The idea of General Relativity posits that gravity is entirely due to the geometry of the universe -- that is, the mass distribution throughout the universe results in the "curving" of spacetime, which gives us the physics we see on a large scale. In the framework of General Relativity, we find that the universe behaves differently than was predicted in the model of gravitation developed by Newton. We will derive the general relativistic model for a simple system near a …
What Do We Know About Lorentz Symmetry?, Q. G. Bailey
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.
Initial Calibration Of Ccd Images For The Dark Energy Survey, Deokgeun Park '12, H. Thomas Diehl, Douglas Tucker
Initial Calibration Of Ccd Images For The Dark Energy Survey, Deokgeun Park '12, H. Thomas Diehl, Douglas Tucker
Student Publications & Research
Astronomical images taken from a telescope must go through “astronomical image processing” to remove instrumental signatures. The Dark Energy Survey (DES), which will start operations in 2012, will use a 570 megapixel Dark Energy Camera (DECam) to study the mystery of the acceleration of the expanding universe. The DECam will use DES filters and 74 of a new type of astronomical Charge Coupled Device (CCD) that is particularly efficient in detecting near-infrared light. Together, the DES filters and DECam CCDs are optimized for the measurement of redshifts of distant galaxies. In preparation for the DES, data were collected from the …
Probing The Cosmos With Light And Gravity: Multi-Messenger Astronomy In The Gravitational Wave Era, Shane L. Larson
Probing The Cosmos With Light And Gravity: Multi-Messenger Astronomy In The Gravitational Wave Era, Shane L. Larson
Colloquia and Seminars
No abstract provided.
Why Is An Einstein Ring Blue?, Jonathan Blackledge
Why Is An Einstein Ring Blue?, Jonathan Blackledge
Articles
Albert Einstein predicted the existence of `Einstein rings' as a consequence of his general theory of relativity. The phenomenon is a direct result of the idea that if a mass warps space-time then light (and other electromagnetic waves) will be `lensed' by the strong gravitational field produced by a large cosmological body such as a galaxy. Since 1998, when the first complete Einstein ring was observed, many more complete or partially complete Einstein rings have been observed in the radio and infrared spectra, for example, and by the Hubble Space Telescope in the optical spectrum. However, in the latter case, …
The Equivalence Principle, Uniformly Accelerated Reference Frames, And The Uniform Gravitational Field, Gerardo Muñoz, Preston Jones
The Equivalence Principle, Uniformly Accelerated Reference Frames, And The Uniform Gravitational Field, Gerardo Muñoz, Preston Jones
Publications
The relation between uniformly accelerated reference frames in flat spacetime and the uniform gravitational field is examined in a relativistic context. It is shown that contrary to previous statements, equivalence does not break down in this context. No restrictions to Newtonian approximations or small enclosures are necessary.
Whispers From The Cosmos: Listeing To Gravity's Hidden Message, Shane L. Larson
Whispers From The Cosmos: Listeing To Gravity's Hidden Message, Shane L. Larson
Public Talks
No abstract provided.
Gravity Has A Story To Tell: Lisa And The Search For Low Frequency Gravitational Waves, Shane L. Larson
Gravity Has A Story To Tell: Lisa And The Search For Low Frequency Gravitational Waves, Shane L. Larson
Colloquia and Seminars
No abstract provided.
Electromagnetic Radiation From Temporal Variations In Space-Time And Progenitors Of Gamma Ray Burst And Millisecond Pulsars, Preston Jones
Electromagnetic Radiation From Temporal Variations In Space-Time And Progenitors Of Gamma Ray Burst And Millisecond Pulsars, Preston Jones
Publications
A time varying space–time metric is shown to be a source of electromagnetic radiation even in the absence of charge sources. The post-Newtonian approximation is used as a realistic model of the connection between the space–time metric and a time-varying gravitational potential. Rapid temporal variations in the metric from the coalescence of relativistic stars are shown to be likely progenitors of gamma ray burst and millisecond pulsars.
A Dyad Theory Of Hydrodynamics And Electrodynamics, Preston Jones
A Dyad Theory Of Hydrodynamics And Electrodynamics, Preston Jones
Publications
The dyadic calculus is developed in a form suitable for the description of physical relations in curved space. The 4-space equations of hydrodynamics and electrodynamics are constructed using this dyadic calculus. As a demonstration of the relationship between gravity and electrodynamics a time varying metric is shown to generate electromagnetic radiation.
Riemann Tensor Of The Ambient Universe, The Dilaton, And Newton’S Constant, Rossen Ivanov, Emil Prodanov
Riemann Tensor Of The Ambient Universe, The Dilaton, And Newton’S Constant, Rossen Ivanov, Emil Prodanov
Articles
We investigate a four-dimensional world, embedded into a five-dimensional spacetime, and find the five-dimensional Riemann tensor via generalisation of the Gauss (--Codacci) equations. We then derive the generalised equations of the four-dimensional world and also show that the square of the dilaton field is equal to the Newton's constant. We find plausable constant and non-constant solutions for the dilaton. Comment: 5 pages, revtex
Gravity And Electromagnetism In Noncommutative Geometry, Giovanni Landi, Nguyen Ai Viet, Kameshwar C. Wali
Gravity And Electromagnetism In Noncommutative Geometry, Giovanni Landi, Nguyen Ai Viet, Kameshwar C. Wali
Physics - All Scholarship
We present a unified description of gravity and electromagnetism in the framework of a Z 2 non-commutative differential calculus. It can be considered as a “discrete version” of Kaluza-Klein theory, where the fifth continuous dimension is replaced by two discrete points. We derive an action which coincides with the dimensionally reduced one of the ordinary Kaluza-Klein theory.