Bulletin of the American Physical Society
APS April Meeting 2020
Volume 65, Number 2
Saturday–Tuesday, April 18–21, 2020; Washington D.C.
Session Y15: New Perspectives in Gravitational Physics and ElectrodynamicsLive
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Sponsoring Units: DGRAV Chair: Richard O'Shaughnessy, Rochester Institute of Technology Room: Virginia B |
Tuesday, April 21, 2020 1:30PM - 1:42PM Live |
Y15.00001: Space-Time Splitting and the Newtonian Limit in General Relativity Theory Maik Reddiger Is there a well-motivated, mathematical separation of space and time in general relativity? Common approaches are either coordinate-dependent, require additional constraints and geometric structures, or are physically unjustified. As a remedy, we motivate an approach via individual observers and their past light cones, leading to the definition of `observer mappings'. The concept of a frame of reference is defined mathematically, tying sensibly to the general theory. Results include statements on the domain and smoothness of observer mappings, the relation between `actual' and `observed' causality, as well as the question of how the `observer spacetime' relates to the actual one. As the employed concepts of space and time need to reduce to the Newtonian ones in an approximation, the theory provides a natural framework for the Newtonian limit. For mass points, this translates to expanding an `equation of observed motion' in inverse powers of the speed of light. In this equation `actual' forces and pseudo-forces can generally be distinguished. For `inertial frames' in Minkowski spacetime, a pseudo-force exists due to the change of clock rate of the accelerated `observed observer'. In the zeroth order, the pseudo-force disappears and Newton's second law is indeed obtained. [Preview Abstract] |
Tuesday, April 21, 2020 1:42PM - 1:54PM Live |
Y15.00002: Theoretical Gravity: Graviton Dynamics George Schuhmann This analysis explores gravitons from a particle perspective and examines how relativistic particle dynamics applied to gravitons can be seen to reproduce the observed effects of gravity. Individual gravitons are seen as massless quanta (like photons) that have energy in the form of momentum in accord with Special Relativity's E $=$ pc. A hypothetical field of gravitons is posited as a dynamic relativistic gas interacting with massive particles. Cosmological implications are presented, and an idealized experiment to detect individual graviton interactions is proposed. [Preview Abstract] |
Tuesday, April 21, 2020 1:54PM - 2:06PM Live |
Y15.00003: Special Relativity in Space-Time and Gravity in its Tangent Space Energy-Momentum Douglas Sweetser When two observers look at the same thing they measure things uniquely. A relativity theory tells us how we do a calculation that both observers agree upon. Special relativity applies to space-time. All inertial observers agree on the speed of light. The zero interval forms the light cone whose intersection defines the origin. All inertial observers can calculate the interval between any pair events and agree: $ t^2 - R^2 = t'^2 - R'^2 = \tau^2 $ which form parabolas. The Lorentz group characterizes the symmetry. All the changes for gravity happen in the phase space of space-time governed by the Poincaré group. A phase space of space-time can be converted into an energy-momentum graph. Energy and angular momentum are conserved. The zeroes in energy-angular momentum space are the horizontal and vertical axes. My hypothesis is that non-inertial observers in a gravitational field will agree on the product of energy and angular momentum which forms hyperbolas but at 45 degrees to those in special relativity. A transformation law can be derived showing that $E' = E/\gamma = m \frac{d t}{d \tau}/\gamma, P' = \gamma P = \gamma m \frac{d R}{d \tau}$. The Newtonian gravitational escape velocity for the gamma is consistent with light bending tests but not higher order experiments. [Preview Abstract] |
Tuesday, April 21, 2020 2:06PM - 2:18PM Live |
Y15.00004: A Unified Electro-Gravity Theory of a Spinning Electron, and the Fundamental Origins of the Fine Structure Constant and Quantum Concepts Nirod Das A new Unified Electro-Gravity (UEG) theory is developed to self-consistently model a spinning electron. In its basic form, the UEG theory introduces a modified gravitational field proportional to the energy density surrounding the charge, with the constant of proportionality referred to as the UEG constant. The resulting stable mass, its associated classical radius, and the UEG constant, are shown to be closely related to the fine structure constant of electrodynamics, revealing - for the first time - the fundamental origin of the fine structure constant. The UEG theory of the spinning electron could also explain different quantum mechanical and quantum electrodynamic principles/phenomena, such as: (a) the Casimir effect in terms of the new UEG force, (b) the energy and frequency shifts in any electrodynamic transition in terms of a non-linear mixing process of the associated UEG and electromagnetic fields, (c) the quantized nature of the charge by directly linking it to quantization of the angular momentum through the UEG theory, (d) quantum wave frequency in terms of the spinning UEG field, and (c) the quantum wave-particle duality through an equivalent pilot-wave concept, based on the inseparable nature of the physical central charge and its surrounding spinning UEG field. [Preview Abstract] |
Tuesday, April 21, 2020 2:18PM - 2:30PM Live |
Y15.00005: Implications of transformation properties of the source term in the classical Kaluza theory for modifications to the Maxwell equations L.L. Williams Kaluza obtained a unification of general relativity (GR) and classical electromagnetism from the fact that their respective field equations and equations of motion follow from GR written in 5 dimensions (5D). An additional scalar field is necessitated by the 5D framework, and the full field equations were developed long after the theory was abandoned. To correct some errors in the English-language literature, in 2015 we used tensor algebra software to provide the first English-language description of the correct Kaluza vacuum field equations and their Lagrangian. In the present work, we consider the Kaluza source term in the field equations, and its covariance properties in 4D and 5D. A typical 5D fluid source term qualitatively reproduces the source terms in the 4D Einstein and Maxwell equations, matching the correspondence in the curvature terms. Yet the 5D source terms in various references were restricted to certain limits, or not made covariant in 5D. When standard covariance considerations are applied to the 5D Kaluza source term, intriguing modifications to the Maxwell equations emerge from the scalar field. One preliminary result is a saturation electric field from electrostatic sources, above which no additional added charge can increase the electric field strength. [Preview Abstract] |
Tuesday, April 21, 2020 2:30PM - 2:42PM |
Y15.00006: Toy models for scalar QED and gravitational decoherence Qidong Xu, Miles Blencowe We investigate the dynamics of two quantum mechanical oscillator system-bath toy models obtained by dimensionally truncating scalar QED and linearized gravity coupled to a massive scalarfield. The scalar QED toy model approximately maps onto an oscillator system subject to two-photon damping, while the scalar-gravity toy model maps onto the phase damped oscillator. The toy models provide useful insights into solving for open system quantum dynamics relevant to thefull scalar QED and weak gravitational field systems, in particular the decoherence of initial scalar field system superposition states. [Preview Abstract] |
Tuesday, April 21, 2020 2:42PM - 2:54PM |
Y15.00007: Alternative Gravity Explorations for the Bottema et al. 2015 and Carignan et al 2013 Surveys James O'Brien, Thomas Chiarelli In the last few years, alternative gravity theories have seen increased interest due to the lack of observational evidence of dark matter. Further, new empirical patterns found in rotation curve data such as the Radial Acceleration Rule (RAR) have given new testable features for gravitational theories. In this talk, we revisit a two very popular surveys of galaxies (Carignan et al 2013 and Bottema et al 2015) which when published were shown to be problematic for alternative gravity. Here, we apply the most recent observational parameters to the surveys and provide fits of Conformal Gravity, and MOND and show how these theories can apply to the system. We also provide the fits to the RAR and Tully Fisher relation for each theory and discuss how the RAR may allow for some confining of parameters in the fitting procedure. [Preview Abstract] |
Tuesday, April 21, 2020 2:54PM - 3:06PM On Demand |
Y15.00008: The connection between electric charge, gravitation, and the Feynman sum over all histories view of quantum electrodynamics DT Froedge In the introduction to Feynman's\textit{ Six Easy Pieces} it was said: ``You could not imagine the sum-over-histories picture being true for a part of nature and untrue for another part. You could not imagine it being true for electrons and untrue for gravity'' The purpose of this paper is to show that Gravitation and Electric Charge are the result of the interaction of the Feynman path photons. Feynman proposed that for a photon, or any particle, going from one point to another, there is a probability of the particle has traveled every possible path, and by very accurate measurements of quantum effects there is every reason to believe that this is true. It is shown that the interaction of these Feynman path photons generated by mass particles change the index of refraction of space, and can constitutes the effects of gravitation and electric charge. [Preview Abstract] |
Tuesday, April 21, 2020 3:06PM - 3:18PM |
Y15.00009: Orbital Mass, Charge, and Completeness of the Quantum Nature of Atoms Rasulkhozha S. Sharafiddinov The atomic system [1] requires one to follow the logic, at the quantum mechanical level, of each component of the naturally united force from the point of view of the interacting objects of an intraatomic behavior. It chooses herewith the sizes of Newton and Coulomb forces between the nucleus and its satellite so that in the presence of the Planck mass and charge $m_{pl}=\left(\frac{\hbar c}{G_{N}}\right)^{1/2}, \, \, \, \, e_{pl}=(4\pi\epsilon_{0}\hbar c)^{1/2},$ their explicit values will be connected, on the disclosed quantum basis, with the orbital mass and charge $m_{sl}^{o}=(b_{m}^{sl}m_{s}m_{l})^{1/2}, \, \, \, \, e_{sl}^{o}=(b_{ch}^{sl}e_{s}e_{l})^{1/2}.$ The availability of the dimensionless multipliers $b_{m}^{sl}$ and $b_{ch}^{sl}$ in them implies the existence in a system of any $m_{sl}^{o}$ and $e_{sl}^{o}$ at the quantum mechanical level. They define the speed ${\it v}_{ls},$ radius $r_{ls},$ full orbital energy $E_{ls},$ and thus directly the period $T_{ls}$ of the revolution of a particle $l$ around the nucleus $s$ in the mass-charge structure [2] dependence of the united gauge invariance of an intraatomic unified force. [1] R.S. Sharafiddinov, Phys. Essays 32, 358 (2019). [2] R.S. Sharafiddinov, Phys. Essays 29, 410 (2016). [Preview Abstract] |
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