Cosmology, Relativity, and Gravity Commons^™

Linking The Population Of Binary Black Holes With The Stochastic Gravitational-Wave Background, Olivia X. Laske

Macalester Journal of Physics and Astronomy

The astrophysical stochastic gravitational-wave background (SGWB) is the product of overlapping waveforms that create a single unresolvable background. While current LIGO sensitivity is insufficient to uncover the SGWB, future space-based detectors and Third Generation (3G) experiments are expected to probe deep enough for detection. Predictions of the SGWB can constrain future searches as well as provide insight into star formation, merger history, and mass distribution. Here, three primary methods are used to calculate a theoretical SGWB. The first method integrates over a precomputed mass distribution probability grid, while the second and third employ Monte Carlo integration with simulated data. After …

The Black-To-White Hole Transition, Farshid Soltani

Electronic Thesis and Dissertation Repository

Classically, an isolated black hole is a stable gravitational object. If however semiclassical effects are taken into account, an isolated black hole can be shown to slowly radiate its mass away in a process called evaporation. At the end of the evaporation process, when the size of the horizon becomes Planckian, the quantum nature of the gravitational field can no longer be neglected and the dynamics of the horizon is governed by quantum gravity. The main objective of this thesis is the systematic investigation of a tentative scenario for the “end of the life” of a black hole: the black-to-white …

Simulating Continuous Gravitational Waves, Ivan Mihael Villalba Moran

SACAD: John Heinrichs Scholarly and Creative Activity Days

Using a table-top Michelson Interferometer to replicate Laser Interferometer Gravitational-Wave Observatory (LIGO) arrangement, we use sound waves to simulate Continuous Gravitational Waves (CWs). Using the NumPy package in Python programming, we recover the frequency of the injected sinusoidal signal using the mathematics of the Fourier Transform. Currently, we are trying to implement the Hidden Markov Model along with the Viterbi Algorithm as a method to detect Wandering Continuous Gravitational Waves.

Characterizing And Mitigating Transient Noise In Ligo Observatories For Gravitational Wave Detection, Jane Glanzer

LSU Doctoral Dissertations

The existence of gravitational waves is predicted by Albert Einstein's Theory of General Relativity. Commonly referred to as "ripples in spacetime", these waves are generated by some of the most violent and energetic processes in the universe. Despite their theoretical prediction over a century ago, it wasn't until 2015 that the Advanced LIGO (aLIGO) interferometers in Hanford, WA and Livingston, LA directly detected gravitational waves for the first time, confirming Einstein's theory and ushering in a new era of astrophysics.

Detecting gravitational waves requires incredible precision. Because of the extreme sensitivity required, it is possible for the gravitational wave data …

Neutrino’S Non-Zero Electric Potential As An Origin Of Gravitation, Domain Structure And Expansion Of The Universe., Polievkt Perov

College of Arts & Sciences Faculty Works

The axial electric potentials of neutrinos as neutral composite structures, while being very small at large distances, do not vanish, and the same can be said about the neutrino “asymmetric dipoles” (paired neutrinos of not the same kind). Depending on the orientation of the “asymmetric dipole”, its far-field electric potential in some direction can be positive or negative, interacting with other “dipoles” at that large distance attractively or repulsively depending on their mutual orientation. The mutual orientation of the dipoles locally (inside a galaxy) might be such that they are aligned and experience the attractive force toward the local center …

Synchronicity: An Analysis Of Einstein's Halfway Rule, Preslava Nikolova

Rushton Journal of Undergraduate Humanities Research

For the modern world to function, Global Positioning System satellites must synchronize to clocks on Earth. This paper examines a concept that underlies GPS systems, namely Albert Einstein’s halfway rule—the idea that a line of simultaneity exists between two events in different systems. This essay discusses how Einstein used conventionalist methods to establish ½ as a constant value for σ to take advantage of the property of symmetry.

Conventions, Definitions, Identities, And Other Useful Formulae, Robert A. Mcnees Iv

Physics: Faculty Publications and Other Works

As the name suggests, these notes contain a summary of important conventions, definitions, identities, and various formulas that I often refer to. They may prove useful for researchers working in General Relativity, Supergravity, String Theory, Cosmology, and related areas.

Godel, Escherian Staircase And Possibility Of Quantum Wormhole With Liquid Crystalline Phase Of Iced-Water - Part I: Theoretical Underpinning, Victor Christianto, T. Daniel Chandra, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

As a senior physicist colleague and our friend, Robert N. Boyd, wrote in a journal (JCFA, Vol. 1,. 2, 2022), Our universe is but one page in a large book [4]. For example, things and Beings can travel between Universes, intentionally or unintentionally. In this short remark, we revisit and offer short remark to Neil’s ideas and trying to connect them with geometrization of musical chords as presented by D. Tymoczko and others, then to Escher staircase and then to Jacob’s ladder which seems to point to possibility to interpret Jacob’s vision as described in the ancient book of Genesis …

Godel, Escherian Staircase And Possibility Of Quantum Wormhole With Liquid Crystalline Phase Of Iced-Water - Part Ii: Experiment Description, Victor Christianto, T. Daniel Chandra, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

The present article was partly inspired by G. Pollack’s book, and also Dadoloff, Saxena & Jensen (2010). As a senior physicist colleague and our friend, Robert N. Boyd, wrote in a journal (JCFA, Vol. 1, No. 2, 2022), for example, things and Beings can travel between Universes, intentionally or unintentionally [4]. In this short remark, we revisit and offer short remark to Neil Boyd’s ideas and trying to connect them with geometry of musical chords as presented by D. Tymoczko and others, then to Escherian staircase and then to Jacob’s ladder which seems to pointto possibility to interpret Jacob’s vision …

Tests Of General Relativity Through Searches For Lorentz And Cpt Symmetry Breaking, Kellie Ault

Doctoral Dissertations and Master's Theses

An effective field theory framework, the Standard Model Extension (SME), provides an agnostic, systematic test of General Relativity (GR) and its founding spacetime symmetries, Lorentz and CPT symmetry. Violating these symmetries may provide clues toward unifying the physics of the General Relativity and the Standard Model of particle physics. Part of this work involves the merge of theory, data analysis and experiments with gravitational wave (GW) signals from LIGO/Virgo/KAGRA (LVK) detectors. A modified dispersion relation derived from the SME of GWs is implemented into the LIGO Scientific Collaboration Algorithm Library Suite (LALSuite), where a joint Bayesian inference of the source …

Cosmic Diffuse Neutrino And Gamma-Ray Backgrounds In The Mev Regime, Ilukpitiye Samalka Anandagoda

All Dissertations

Cosmic Multi-Messenger backgrounds include relic diffuse components created in the early Universe and contributions from individual sources. In this dissertation, I present the work done in Anandagoda (2019); Anandagoda et al. (2020, 2023) where type Ia (SNe Ia) and core-collapse supernovae (CCSNe) contributions to the diffuse neutrino and gamma-ray backgrounds in the MeV regime are studied. These backgrounds are referred to as DSNB and DSGB respectively. Based on this work, the diffuse SN Ia background is ~10⁶ times lower (for electron antineutrinos) than the CCSN background making it negligible. The predicted DSNB electron antineutrino flux at earth in the …

Simulating The Eccentricity Evolution Of Accreting Equal-Mass Binaries: Numerical Sensitivity To The Computational Domain Size And Grid Resolution, Zhongtian Hu

All Theses

With high resolution hydrodynamics simulations, we show that the optimal values of domain radius and grid resolution for the software Sailfish when simulating time-based eccentricity evolution of equal mass, non-circular accreting binaries in a circumbinary disk to be $r_{\rm out} \leq 15a$ and $\delta x / a \le 0.01 $. These values provide a useful guideline for optimizing the performance of simulation runs while maintaining scientific accuracy. Each artificial parameter is probed with 15 runs of 2000 orbits each.

Development And Testing Of A New Method For Velocity-Selecting White Dwarfs From Gaia By Galactic Population, Joseph Hammill

Doctoral Dissertations and Master's Theses

The detailed processes by which spiral galaxies form remains an open question in modern cosmology. Observations of the current configuration of spiral galaxies including the Milky Way reveal thin and thick disk and halo populations which must all be accounted for in formation theories and likely have distinct ages. Using the Milky Way as an example to probe this question, we are studying the formation history of these structures.

This work details our approach to age-dating the galaxy, velocity-selecting targets from a sample of white dwarfs from the Gaia DR3 catalog that have also been age-analysed using BASE-9. BASE-9 uses …

Cosmological Vector Fields And Constraining The Neutrino Masses, Avery J. Tishue

Dartmouth College Ph.D Dissertations

In this thesis I explore two main topics: the role and consequences of cosmological vector fields, and new ideas for constraining fundamental physics with state-of-the-art experiments. These topics are disparate in content and technique but unified in their attempt to leverage novel approaches to better understand longstanding questions in cosmology. These questions, such as ``What is causing the universe to accelerate today?'' and ``What are the neutrino masses?'', underpin the modern cosmological paradigm. They play a key role in our understanding of cosmic history, the formation of structure, and the fate of our universe. Answers to or hints about these …

Mapping Galactic Acceleration With Pulsar Timing, Abigail Moran

University Scholar Projects

We have conducted a cross match of objects in Gaia Early Data Release 3 and millisecond pulsars (MSPs) in the International Pulsar Timing Array’s Data Release 2 (IPTA DR2) to identify binary systems. Gaia has parallax measurements for these optical companions, which we combine with pulsar timing based parallax measurements to calculate new combined MSP distances. Through this crossmatch with IPTA DR2 we improved five distance measurements and found the first parallax measurement for one MSP.

Using this Gaia crossmatch method now with a well-timed subset of the Australia Telescope National Facility’s database, we found three new pulsar distances. We …

Constraining H0 Via Extragalactic Parallax, Nicholas Ferree

Honors Theses

We examine the prospects for measurement of the Hubble parameter 𝐻₀ via observation of the secular parallax of other galaxies due to our own motion relative to the cosmic microwave background rest frame. Peculiar velocities make distance measurements to individual galaxies highly uncertain, but a survey sampling many galaxies can still yield a precise 𝐻₀ measurement. We use both a Fisher information formalism and simulations to forecast errors in 𝐻₀ from such surveys, marginalizing over the unknown peculiar velocities. The optimum survey observes ∼ 102 galaxies within a redshift 𝐻₀max = 0.06. The required errors …

Characterization Of Extended Uncertainty Principle Black Holes, Juan Uribe, Jonas Mureika

Honors Thesis

Black Holes are special objects as they are at the intersection of Quantum Mechanics and General Relativity. A central tenant of quantum mechanics is the Uncertainty Principle that dictates we cannot know with complete certainty position and momentum at the same time. The Extended Uncertainty Principle introduces a position-related uncertainty correction L_* to account for General Relativity. In a previous paper, a black hole metric associated with the Extended Uncertainty Principle was derived, by modifying the metric function of a Schwarzschild black hole. This metric introduces near-horizon structures that should produce observable effects, such as love numbers, gravitational wave echoes, …

New Physics In The Age Of Precision Cosmology, Vivian I. Sabla

Dartmouth College Ph.D Dissertations

The Lambda-cold dark matter (LCDM) model has become the standard model of cosmology because of its ability to reproduce a vast array of cosmological observations, from the earliest moments of our Universe, to the current period of accelerated expansion, which it does with great accuracy. However, the success of this model only distracts from its inherent flaws and ambiguities. LCDM is purely phenomenological, providing no physical explanation for the nature of dark matter, responsible for the formation and evolution of large-scale structure, and giving an inconclusive explanation for dark energy, which drives the current period of accelerated expansion.

Furthermore, cracks …

Analog Cosmology And Superfluidity In Atomic Gases And Electronic Materials, Anshuman Bhardwaj

LSU Doctoral Dissertations

We present a study of analog cosmological models in Bose-Einstein condensates (BEC) and in graphene, and superfluidity in a box-shaped traps. We start by examining the dynamics of a Bose-Einstein condensate (BEC) trapped inside an expanding toroid that can realize an analog inflationary universe. The expanding condensate forces phonons to undergo redshift and damping due to quantum pressure, owing to the thinness of the ring. We predict that such expanding BECs can exhibit spontaneous phonon creation from the vacuum state and show how it would manifest in the atom density and density correlations and discuss connections with the inflationary theory. …

Stellar Atmosphere Models For Select Veritas Stellar Intensity Interferometry Targets, Jackson Ladd Sackrider, Jason P. Aufdenberg, Katelyn Sonnen

Beyond: Undergraduate Research Journal

Since 2020 the Very Energetic Radiation Imaging Telescope Array System (VERITAS) has observed 48 stellar targets using the technique of Stellar Intensity Interferometry (SII). Angular diameter measurements by VERITAS SII (VSII) in a waveband near 400 nm complement existing angular diameter measurements in the near-infrared. VSII observations will test fundamental predictions of stellar atmosphere models and should be more sensitive to limb darkening and gravity darkening effects than measurements in the near-IR, however, the magnitude of this difference has not been systematically explored in the literature. In order to investigate the synthetic interferometric (as well as spectroscopic) appearance of stars …