Bulletin of the American Physical Society
Four Corners Section 2022 Meeting
Volume 67, Number 14
Friday–Saturday, October 14–15, 2022; Albuquerque, New Mexico
Session M02: Gravitation / Cosmology II |
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Chair: Dinesh Loomba, University of New Mexico Room: UNM PAIS 1160 |
Saturday, October 15, 2022 1:00PM - 1:12PM |
M02.00001: Resolving the Hubble trouble with a variation of "constants" Kylar Greene, Francis-Yan Cyr-Racine Measurements of the early- and late-time Universe disagree on the value of the local expansion rate, H0, at a level of 5σ with no clear solution in sight. Utilizing a variation of the fundamental constants α and me along with a newly revealed symmetry of cosmological observables, we demonstrate the ability to generate CMB spectra which agree with observations while having high values of H0. |
Saturday, October 15, 2022 1:12PM - 1:24PM |
M02.00002: Meeting Challenges at the Next Frontier in Numerical Relativity David W Neilsen, Eric Hirschmann, Milinda Fernando, Hari Sundar Numerical relativity has been a frontier problem in computational science for over fifty years. As gravitational wave detectors continually improve, and new detectors come online, a new challenge will be to compute waveforms with higher fidelity and for a broader array of possible sources. I will talk about some of the recent work in numerical relativity to model binary black holes for gravitational wave analysis. We have developed Dendro-GR, a new computational platform for numerical relativity that uses a highly scalable octree with sparse, wavelet-based refinement. I will present some of initial results obtained with Dendro-GR for merging black hole binaries with different mass ratios. |
Saturday, October 15, 2022 1:24PM - 1:36PM |
M02.00003: About the foundations of modern cosmology: cosmological tests of the Copernican principle. David F Camarena Torres The standard paradigm of modern cosmology relies on a set of fundamental assumptions that simplify and make possible the modeling of the Universe. Among these critical hypotheses, there is the presumption that we do not occupy a special place in the Universe, the so-called Copernican principle. The assumption of this principle constrains the degrees of freedom allowed by the theory, and, in particular, leads to a spatially homogeneous and isotropic space-time. We present a program to observationally test the Copernican principle. Using the latest cosmological data, we test the Copernican principle by placing constraints on radial deviations of the FLRW space-time. We also forecast the precision with which future surveys, such as DES, Euclid, and LSST, will be able to test the Copernican principle and test their ability to detect any possible violations. Furthermore, we investigate if the 5σ discrepancy between the early and late times determinations of the Hubble constant could be a hint of a violation of the assumption of homogeneity. |
Saturday, October 15, 2022 1:36PM - 1:48PM |
M02.00004: Treasure Hunting in the Classical Double Copy Max W Pezzelle The classical double copy relates exact solutions in general relativity with those of classical linearized Yang-Mills theory. In this presentation I describe the work I have done on understanding the classical double copy from various viewpoints. Using the Kerr-Schild double copy, I analyze the single copy of a rotating nonsingular black hole and analyze its horizon structure to probe the relationship between the presence of horizons on the gravity side and the single copy field on the gauge theory side. Next, I describe the mapping between the surface gravity of static spherically symmetric black holes and the force on a test particle due to the single copy field of the black hole. I also describe potential routes to extending this map to more general black holes, specifically ones which are rotating. Finally, inspired by the extended Weyl double copy for spacetimes possessing sources, I reinterpret the single copy of the Taub-NUT metric as being comprised of two terms each being sourced by a separate parameter (the mass and the NUT charge). |
Saturday, October 15, 2022 1:48PM - 2:00PM |
M02.00005: Chaos Analysis of Post-Minkowski/ Post-Newtonian Kozai-Lidov Systems Justin C Tackett, David W Neilsen We consider chaos in the general relativistic three-body problem. We measure Lyapunov exponents of this system in different ways, using Newtonian gravity, and the post-Newtonian and post-Minkowski approximations to general relativity. We focus on hierarchal three-body systems that are conducive to the Kozai-Lidov mechanism. We evolve the systems numerically and compare chaos from one system to another under a variety of parameters. Studying these systems may help explain the origins of intermediate-mass black holes. |
Saturday, October 15, 2022 2:00PM - 2:12PM |
M02.00006: Hidden Symmetries in Black Holes Luis Fernando Temoche Hurtado, Maria J Rodriguez, Alexandra Chanson, Victoria L Martin In this presentation we aim to discuss the existence of the so-called hidden conformal symmetries for the case of black rings doughnut shaped black hole solutions of General Relativity in five spacetime dimensions. Through the application of the monodromy technique to the massless Klein Gordon equation in the near horizon black ring regions, we compute the temperatures and central charges of the 2-dimensional conformal theory duals (2D-CFT) of the system. Similar results are obtained from the study of the Casimir operator for these geometries. Considering the recently proposed 2D-CFT duality for Kerr and 5D Myers-Perry black holes, we conjecture the general features required in the black hole solutions to exhibit a 2D conformal field duals. |
Saturday, October 15, 2022 2:12PM - 2:24PM |
M02.00007: Nonlinear Evolution of Black Holes in Quadratic Gravity Hyun Lim, Aaron Held We present the first numerical-relativity simulations for black holes in Quadratic Gravity, i.e., including the leading-order (quadratic) curvature corrections to General Relativity. We review the nonlinear degrees of freedom and discuss a well-posed initial value formulation for Quadratic Gravity, both in spherical symmetry and in (3+1) dimensions. In spherical symmetry, self-convergence tests and decaying constraint violations confirm numerically stable evolution of perturbations on Minkowski as well as Schwarzschild spacetime. For the first time, we will also present full (3+1) simulations of black-hole initial data, which enable ongoing work to simulate black-hole binary systems in Quadratic Gravity. |
Saturday, October 15, 2022 2:24PM - 2:36PM |
M02.00008: The Vacuum Space-Time Lattice; An Answer to Stellar G-Band Absorption Richard M Price I have determined the spacing of the vacuum space-time lattice (VSTL) . Within this lattice there are 22 virtual particle entities, Geons, at each point, or distributed between them. These are probably charged. All together this assembly determines the electromagnetic properties of the vacuum, the speed of light, and mediates pair production in the vacuum. It also explains the well-known absorption in the G band in astronomical spectra. |
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