Bulletin of the American Physical Society
2017 Fall Meeting of the APS Prairie Section
Saturday–Sunday, November 11–12, 2017; University of Illinois at Chicago, Chicago, Illinois
Session B1: Session B |
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Chair: Olga Evdokimov, University of Illinois at Chicago Room: UIC Student Center East 302 |
Saturday, November 11, 2017 4:00PM - 4:30PM |
B1.00001: Dark Matter: Where Cosmology Meets Particle Physics Invited Speaker: James A. Unwin Cosmological measurements and astrophysical observations point to the presence of new particles, "Dark Matter", which do not have significant interactions with the normal particles of the Standard Model of Particle Physics. This is one of the most striking indications that the Standard Model is incomplete - I will outline the evidence for dark matter and highlight a selection of different theories which endeavour to explain the nature and origin of dark matter. [Preview Abstract] |
Saturday, November 11, 2017 4:30PM - 4:42PM |
B1.00002: Validation of Synthetic Sky Catalogs Joseph Hollowed With first light approaching for the deepest and largest sky surveys ever preformed, such as LSST, the astronomy community is working hard to prepare for unprecedented data releases in the coming years. In the interim, it is highly desirable to have synthetic datasets which will emulate that of the future survey products. Such datasets will allow working groups to test and refine analysis/processing pipelines, which will ensure scientific efficiency upon data arrival. To this end, we are working to generate accurate synthetic galaxy catalogs, taking advantage of some of the largest cosmological simulations currently available, and detailed models of galaxy evolution. This talk will give an introduction to how and why these catalogs are created, and especially focus on the iterative testing, improvement, and validation necessary for their development. [Preview Abstract] |
Saturday, November 11, 2017 4:42PM - 4:54PM |
B1.00003: The Milkomeda Merger Janki Brahmbhatt The Andromeda and Milky Way galaxies are on a collision course; they're set to collide in about 4 billion years, after which, the two originally spiral-shaped galaxies are going to transmute into a single elliptical galaxy. The purpose of this project is to create a 3D model of the Milkomeda merger by using and modifying a galaxy merger code available on the Astrophysics Source Code Library. The code uses a restricted 3-body approach to model the morphology of actual interacting galaxies. The data will be displayed at UIC's Electronic Visualization Laboratory at CAVE2 where, with the aid of specially engineered glasses, viewers will find themselves amidst a galaxy merger visible from multiple perspectives. [Preview Abstract] |
Saturday, November 11, 2017 4:54PM - 5:06PM |
B1.00004: A deeper look into the relationship between mass density and the curvature of spacetime John Laubenstein John Wheeler is credited with the quote that is commonly stated as: "Mass tells space-time how to curve, and space-time tells mass how to move." While one needs to be careful in using language to describe mathematics, in this case, the quote is remarkably accurate in describing the Einstein Field Equations (for the simplest case of a non-rotating, non-moving, non-electromagnetic mass where the stress-energy tensor reduces to the mass density of the gravitating body). One the one side of the equality lies an expression for the curvature of spacetime and the other side the mass density of the gravitating body that defines the curvature. However, this type of statement can be applied to any equality where the properties associated on the left side of an equation can be thought of as defining the properties on the right side. For example, per unit mass, kinetic energy defines the velocity squared of an object, just as an object's velocity tells you something about its kinetic energy. Yet, these classical equalities all break down as velocities approach the speed of light. This talk looks at some of the parallels between General Relativity and classical mechanics to ask whether gravitation is really as simple as expressed by John Wheeler's quote. [Preview Abstract] |
Saturday, November 11, 2017 5:06PM - 5:18PM |
B1.00005: Calculation of Time-Dependent Wave Functions using the PIQTr Model Torrey Saxton, Zachary Temple, Allison Harris The Path Integral technique is an alternative formulation of quantum mechanics that is based on a Lagrangian approach. In its exact form, it is completely equivalent to the Hamiltonian-based Schr\"{o}dinger equation approach. Developed by Feynman in the 1940's, following inspiration from Dirac, the path integral approach has been widely used in high energy physics, quantum field theory, and statistical mechanics. However, only in limited cases has the path integral approach been applied to quantum mechanical few-body scattering. We will present a theoretical and computational development of our Path Integral Quantum Trajectory (PIQTr) model for use in the study of atomic collisions. Preliminary results will be presented for some simple systems, and numerical challenges will be discussed. [Preview Abstract] |
Saturday, November 11, 2017 5:18PM - 5:30PM |
B1.00006: Relativistic Effects in Quantum Mechanical Potential Scattering. Creighton Lisowski, Richard Pelphrey, Rainer Grobe, Q. Charles Su We examine the effect of relativistic mechanisms on the scattering of an incoming electron with one-dimensional attractive and repulsive potentials. We compare the energy dependence of the transmission coefficients obtained from the Dirac equation with the non-relativistic limit of the Schr\"{o}dinger equation. This limit requires the introduction of discontinuous wave functions. When transmission expansion in orders of 1/c diverges we propose a numerical method that permits us to compute the sum of a diverging series from only the first N terms by generalizing the traditional Borel technique. [1,2]. We acknowledge the support by the National Science Foundation. [1] C. Lisowski, S. Norris, R. Pelphrey, E. Stefanovich, Q. Su, R. Grobe, Ann. Phys. 373, 456 (2016) [2] Q.Z. Lv, S. Norris, R. Pelphrey, Q. Su, R. Grobe, Comp. Phys. Comm. 219, 1 (2017). [Preview Abstract] |
Saturday, November 11, 2017 5:30PM - 5:42PM |
B1.00007: Removal of Self Interactions Jonathan Unger, Rainer Grobe, Q. Charles Su We propose a theoretical framework that permits us to eliminate the unphysical self-repulsion that occurs if a spatially localized charged particle interacts with its own electric field. As an example of this framework, we study the time-resolved interaction between an electronic and positronic wave packet by solving the coupled set of two-particle Dirac-Maxwell equations. Here the unwanted self-repulsion can be removed by separating the total electric field into two portions, each of which is generated by only one particle and is evolved independently of the other. For example, the Maxwell equation for the electronic field has only the electronic charge density as a source term and only this field is coupled to the positron in the two-particle Dirac equation. [1-4] We acknowledge the support by the National Science Foundation. [1] S. Norris, J. Unger, Q. Z. Lv, Q. Su, and R. Grobe, Phys. Rev. A 93, 032131 (2016). [2] Q.Z. Lv, J. Unger, Y.T. Li, Q. Su and R. Grobe, Phys. Rev. A 95, 023416 (2017). [3] Q.Z. Lv, J. Unger, Y.T. Li, Q. Su and R. Grobe, Euro. Phys. Lett. 116, 40003 (2016). [4] N.D. Christensen, J. Unger, S. Pinto, Q. Su and R. Grobe, Ann. Phys. (submitted). [Preview Abstract] |
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