Bulletin of the American Physical Society
APS March Meeting 2022
Volume 67, Number 3
Monday–Friday, March 14–18, 2022; Chicago
Session D47: Undergraduate Research VRecordings Available Undergrad Friendly

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Sponsoring Units: APS/SPS Chair: Andrew Zeidell, Wake Forest Univ Room: McCormick Place W470B 
Monday, March 14, 2022 3:00PM  3:12PM 
D47.00001: Particle Dynamics Through the Earth: A Study of NonZero Tunnel Diameters Walker T Hayes A standard problem in undergraduate mechanics derives the trajectory of a particle that has been dropped through a gravity tunnel passing through the center of the Earth as simple harmonic oscillation, assuming constant earth density and negligible tunnel diameter. We show that when the more accurate PREM density profile and nonnegligible tunnel diameters are taken into consideration, significant deviations from harmonic oscillations are observed along with reduced particle speeds. Furthermore, we report that a particle traveling perpendicular to the axis of the gravity tunnel is unable to reach the center of the earth beyond a critical tunnel diameter of 71.36% of the earth's diameter under a constant density, or 72.36% of the diameter under the PREM density model. When the rotation of the earth is incorporated, the particle trajectories occasionally extend beyond the surface of the earth at large tunnel diameters, owing to tunnelinduced nonuniformity of the earth's potential energy surface. In addition, we numerically calculate the brachistochrones connecting two points on the surface for various tunnel diameters using the PREM density profile. Our results highlight the effect of nonnegligible tunnel diameters on the overall potential energy surface and particle dynamics. 
Monday, March 14, 2022 3:12PM  3:24PM 
D47.00002: A Study of Composition, Texture and Space Weathering Effects on Asteroid (101955) Bennu Antara Sen, Beth E Clark, Dante S Lauretta The focus of our work has been asteroid (101955) Bennu, target of NASA’s OSIRISREx mission. The first part of our work was creating twocomponent laboratory simulations of the asteroid surface’s texture and composition. We found a physical model whose composition and texture best fit the nearinfrared spectrum of the asteroid, as observed from the spacecraft: a dry mixture of 90% saponite (SAP105) with 10% carbon lampblack (LCA101) dissolved in a 1:2 powder to water slurry, then baked and broken into rough chunks. 
Monday, March 14, 2022 3:24PM  3:36PM 
D47.00003: Modeling and Manufacturing Baffle Panels to Reduce the Impact of Sidelobes in Cosmic Microwave Background Telescopes Kate Okun Three Mirror Anastigmat (TMA) Cosmic Microwave Background (CMB) telescopes experience a substantial reduction in image quality caused by significant sidelobe pickup. TMA telescopes have specularly reflecting internal walls that can amplify the effects of the scattered light entering the instrument at wide angles, thus worsening the resulting sidelobes. We aim to reduce the contrast of the sidelobes by lining the cabin in white noise surfaces, called baffle panels, designed to scatter light over a wide range of angles, thus diffusing the sidelobe specular peaks into a DC base. Our research focuses on modeling the scattering caused by the white noise surfaces using phasesensitive ray tracing and manufacturing such surfaces at a larger scale. We hope to see our analytical model confirm our previous experimental results from the 90110 GHz range. 
Monday, March 14, 2022 3:36PM  3:48PM 
D47.00004: Analysis of NonPrompt Lepton Backgrounds in FourLepton Events at the ATLAS Experiment Iria Wang In the search for new physics beyond the Standard Model (SM), the ATLAS detector at the Large Hadron Collider (LHC) is collecting an evergrowing collision dataset requiring an increasingly precise understanding of background sources. An ideal candidate for highprecision studies of the SM are fourlepton events, which have final states of two sameflavor oppositecharge lepton pairs. These events have contributions from several interesting SM processes including single Z boson production, Higgs boson production, and onshell ZZ production, as well as sensitivity to new physics beyond the SM. However, nonprompt leptons produced by secondary hadron decays or as artifacts of misreconstructions contaminate the dataset and must be suppressed. These backgrounds are subject to rare detector effects, and are therefore preferentially studied using data driven methods. Through comparisons with Monte Carlo simulated data, I studied a sample of collision data in which the final states include a pair of leptons, and any additional third lepton is likely to be nonprompt. I investigated the nonprompt lepton suppression methods, and refined the nonprompt lepton region to reduce systematic uncertainties on background measurements. 
Monday, March 14, 2022 3:48PM  4:00PM 
D47.00005: Effect of cavityinduced longrange interactions between twocomponent fermions on optical lattices Andrew Zimmerman, Theja De Silva We study interacting twocomponent fermions subjected to a periodic optical lattice potential and an optical cavity. In addition to the tunneling interaction and onsite interaction modified by the optical lattice potential, the cavity photons mediate longrange interactions between Fermi atoms. At the steadystate limit of the cavity photon decay, the photon mediated longrange interaction that contains a spinflip term. After decoupling this spinflip interaction term using a meanfield theory, we introduce a unitary transformation to convert our Hamiltonian into an effectively sitedependent populationimbalance quasifermion system. We then solve our effective Hamiltonian to study the effect of the longrange interactions on physical properties using standard theoretical approaches. 
Monday, March 14, 2022 4:00PM  4:12PM 
D47.00006: Ground state properties of manybody quantum systems: chaos vs integrability Tamar Leiser, Talía Lezama Mergold Love, Lea F Santos We study the distribution of the ground state energy of different manybody quantum systems and compare it with analytical expressions obtained for small and large random matrices. We find that weak differences in distribution tails can be attributed to the regularity or the chaoticity of the model. 
Monday, March 14, 2022 4:12PM  4:24PM 
D47.00007: Can banded random matrices describe realistic manybody quantum systems? Leon Alper, Tamar Leiser, Lea F Santos Despite the success of full random matrices in describing statistically the spectrum of complex systems, they imply the unphysical scenario of all particles interacting simultaneously. Banded random matrices were introduced in an effort to better approach random matrices to realistic systems. We study powerlaw banded random matrices and show that they capture very well many features of the evolution of realistic disordered spin1/2 chains both in their chaotic regime and in intermediate regions between chaos and localization. 
Monday, March 14, 2022 4:24PM  4:36PM 
D47.00008: Weak disorder perturbation expansion for random resistance networks Sayak Bhattacharjee, Kabir Ramola Random resistance networks are a popular paradigm in statistical physics for modeling transport in disordered media such as semiconductors, spin glasses, and even porous rocks. We study a square lattice where the resistances at each bond are chosen from a statistical distribution. We derive the moments of the nodal voltages and bond currents exactly up to second order in a perturbation expansion in the disorder strength. Further, we construct an order parameter using the bond currents at arbitrary and infinite disorder, which provides a characterization of the behaviour of the system in the weak as well as strong disorder regimes. We predict a square law scaling with weak disorder, which is verified through numerical simulations. Scalings for the strong disorder regime are also obtained numerically, and the susceptibility of the order parameter is shown to diverge at a critical disorder. We compare our results with previous studies that use exponentially distributed resistances at each bond. 
Monday, March 14, 2022 4:36PM  4:48PM 
D47.00009: Dynamic 3D Simulations of Tree and Network Sea Fan Structures ArianaDalia Vlad, Asja Radja, Anna Lappala Sea fans are a variety of corals structured in a flat fanlike pattern of numerous cylindrical polyps. Their morphology has been previously studied through 2D images and digitized data points depicting the structures have been obtained. The project employs polymer physics and molecular simulations to study samples of treelike and network structures and analyze differences in their dynamics. The sea fans' motion was initially simulated with the Largescale Atomic/Molecular Massively Parallel Simulator Molecular Dynamics software by connecting the data points through harmonic bonds and modulating the flexibility/bending stiffness through an angle potential between three particles. Next, hydrodynamics was integrated using Smooth Particle Hydrodynamics and the Constant Energy Dissipative Particle Dynamics. Preliminary analysis of the output through particle displacements computations suggests that tree structures tend to be more dynamic than networks and that the greatest displacements correspond to outer particles, a result consistent with experimental findings. Further analysis of all available structures is necessary to conclusively find the correlation between the morphology of sea fans and their environment. 
Monday, March 14, 2022 4:48PM  5:00PM 
D47.00010: The Effect of Finite Element Mesh Style and Size on NanoOptic Computational Electromagnetic Simulations Joan Matutes, Meredith Magee, Joseph B Herzog Finite element method analysis produces highly accurate computational models for electromagnetics, especially the field of plasmonics. However, mesh size can vary across studies, and how it affects simulation accuracy for nanoscale electromagnetic could use further investigation. Larger mesh elements can reduce computation time, and so an understanding of mesh size upon model accuracy is significant. The purpose of our work is to investigate the relationship between mesh element size and deviancy from expected values of optical characteristics of the nanostructures. Specifically, we are trying to define a maximum mesh element size that retains acceptable deviance from expected values. 
Monday, March 14, 2022 5:00PM  5:12PM 
D47.00011: New Condensed Matter Physics Model of Water Material in its Three Dimensions and Phases Solid (Ice), Liquid (Fluid Water) and Gas (Vapor) Cindy Tianhui Jie In pure water, electrical mobility of hydroxide ion (OH)^{– }and hydronium ion (H_{3}O)^{+}=(H_{2}O)H^{+} are 5 times higher than impurity ions (Na^{+}, Cl^{–}). In 2013, Chihtang Sah delayed retiring from transistor manufacturing and college teaching, to find out why. In June of 2017, he accepted me to work on this project. I noticed at 0°K, only half of the trisector sites between the adjacent tetrahedral oxygens of the hexagonal closed packed ice are occupied by protons, p^{+}, forming a band of proton filled sites. The other half are unoccupied by p^{+}, forming a band of proton unfilled sites. When ice warms up from 0°K, some p^{+} in proton filled band are excited to proton unfilled band, by absorbing propagating longitudinal proton vibrations, leaving some protonfilled sites unoccupied by protons, or occupied by prohols. From pH measurements in liquid water, this protonprohol pair has an activation energy of 540meV. Proton and prohol traps are also formed, but by localized proton vibrations which are fed by the traveling proton and prohol vibrations from the surrounding heat source through the fluid water tank and by the number of BornVon Karman primitive unit cells in the tank. This water lattice model is applicable to Nuclear, Particle, Astro and Cosmo physics at their kinetic energies. 
Monday, March 14, 2022 5:12PM  5:24PM 
D47.00012: First principles thermodynamic modeling of aqueous lead corrosion Alex T Tai, Lauren N Walters, James M Rondinelli The corrosion of lead water pipes is a major public health concern. Treatment strategies aim to induce passivation, the formation of a protective solid layer between the pipe and the water. While prevention of lead corrosion is understood from engineering practices, computational models using decades old data remain unable to accurately predict the behavior of real pipes using thermodynamics alone. Here we calculate free energies of formation for solid lead compounds with density functional theory (DFT) and construct electrochemical phase diagrams for various water conditions. We find that the PerdewBurkeErnzerhof revised for solids (PBEsol) functional with spinorbit coupling is the best choice for this PbH2O system. Our phase diagrams predict the corrosion of lead in standard state water conditions, confirming the need for corrosion inhibitors. We find that lead carbonates form in broad water conditions. However, our model did not find stable lead phosphates, contrary to the historical success of orthophosphate treatments, indicating the need for further investigation. Our work demonstrates the potential for computational materials physics techniques to provide insight into the thermodynamics of lead corrosion. 
Monday, March 14, 2022 5:24PM  5:36PM 
D47.00013: Path Integral Construction of Quantum Propagators for TimeDependent Potentials to Evaluate Work Statistics Taylor Kimball, JeanFrancois S Van Huele The path integral approach to quantum mechanics is an alternative to the Schrödinger equation for finding quantum propagators. This approach generalizes the action principle in classical mechanics with a sum over the infinite number of possible trajectories. It can also be used to calculate the propagator in the case of a timedependent potential. Here, I describe several of these potentials and illustrate the case of a particle in a rigid box with one wall moving uniformly in time, using a semiclassical approximation. Timedependent potentials can be used in quantum thermodynamics as a work parameter, which does work on the system when controlled by an external agent. This leads to a path integral approach to quantum thermodynamics. I illustrate the calculation of the work statistics for the rigid box with one wall moving uniformly in time. 
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