Bulletin of the American Physical Society
2019 Annual Meeting of the APS Far West Section
Volume 64, Number 17
Friday–Saturday, November 1–2, 2019; Stanford, California
Session B03: Poster Session - AMO, Plasma Physics and Education |
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Chair: Alla Safronova, University of Nevada Reno Room: Huang Engineering Center Foyer |
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B03.00001: Control and Automation of an Ultracold Atoms Apparatus via the Labscript Suite T. Garcia, Y. Guzman, H. Khinda, J. Permann, J. Pechkis, H. Pechkis We report on progress to construct an ultracold atom apparatus at California State University, Chico. Computer control via the Labscript suite$^1$ has been completed and allows for autonomous shot-based experimental control of the apparatus. Absorption imaging will be utilized as the main detection tool of the apparatus and allow for the determination of the temperature and density of the atom cloud. A camera driver is under development, which will allow for full control of the scientific camera through Labscript. A low-cost, microcontroller-based shutter driver circuit has been designed and constructed, which allows for automated optical switching of the cooling beams. Finally, we will utilize a master-slave configuration for increased optical power of the cooling and trapping beams. $^1$The Labscript suite was developed by the BEC research group at Monash University in Australia for use in the Spinor BEC lab of Dr. Lincoln Turner and Dr. Russell Anderson, and the Dual Species BEC labs of Professor Dr. Kristian Helmerson. [Preview Abstract] |
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B03.00002: Students' difficulties in solving simple pendulum like problems at community college and four-year college: A case study Mahendra Thapa Simple pendulum like problems are generally included in the college level physics courses or even in high school physics. Students are usually exposed to simple experiment such as finding the time period of a simple pendulum or demo or PhET simulation and relevant questions are included in either formative or summative assessments. To access understanding and difficulties in such problems, non-physics major students taking introductory physics courses (algebra based) were assigned a set of math questions with one question related to simple pendulum as a pre-test and post-test. Data were collected from 300 -- 400 students starting from 2016 Fall at California State University Chico and Yuba Community College Marysville. In this poster, students' responses on that particular question will be presented along with their improvement in math solving skills after taking the physics course. [Preview Abstract] |
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B03.00003: 3D Simulations of Test Particle Propagation in the Fields of Whistler Waves. Kush Maheshwari, Marc Swisdak, James Drake Whistler waves are oscillations in plasma thought to help inhibit energy transport in the solar wind and in galaxy clusters. Previous particle-in-cell (PIC) simulations studying the effect of whistler waves on astrophysical plasmas were restricted to 2D due to computational constraints. To study the full dimensionality of a whistler-mediated plasma, we build a test particle simulation using a Boris stepper algorithm, which preserves numerical accuracy of a particle's energy extremely well. The particles themselves do not generate their own electromagnetic fields or influence the wave. In a one-wave simulation, after verifying that canonical momentum is conserved in the dimensionally invariant direction, we find that kinetic energy is bounded and that particle trajectories are bounded in the plane perpendicular to the guide magnetic field. Adding a second wave not in the same plane as the first wave breaks dimensional invariance in the system, allowing the particles to diffuse arbitrarily far in the plane perpendicular to the guide field. These results suggest there is new physics to be discovered by examining the full dimensionality of plasmas involving whistlers, strengthening the case to perform a full 3D PIC simulation. [Preview Abstract] |
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B03.00004: Non-Adiabatic Molecular Dynamic Simulations of Warm Dense Matter William Angermeier, Ryan Davis, Rebekah Hermsmeier, Thomas White The state and evolution of methane-rich planets, such as Uranus and Neptune, are determined by the properties of the dense and compressed matter in the planet interior. This compressed state, known as warm dense matter (WDM), is typically defined by temperatures of a few electron volts and densities comparable with those of solids. Recent experiments have suggested that non-adiabatic models that go beyond the Born-Oppenheimer approximation are necessary to describe such systems. We employ Wave Packet Molecular Dynamics(WPMD), a technique where the nuclei are treated classically, and the electrons are described as spherical Gaussian wave packets. In order to simulate large systems we use Electron Force Field(EFF) WPMD. EFF utilizes a Hartree product for the electron wavefunction and adds a correction term to the energy to account for Pauli exclusion. We benchmark EFF against orbital-free density functional theory across a broad range of phase space and, where available, experimental results. We show that the approximations within EFF breakdown at the highest densities. In order to extend the region of applicability, we begin to address two of the largest shortcomings of the EFF method, namely improvements to the approximation for the exchange energy and a more physical basis set. [Preview Abstract] |
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B03.00005: 2D Monochromatic X-ray Imaging for Focus Monitoring of High-Power Femtosecond and X-ray Free Electron Lasers J. Trzaska, H. Sawada, T. Daykin, L. Chen, C. Salinas, C. Curry, M. Gauthier, L. Fletcher, G. Glenn, M. Frost, S. Glenzer, H.J. Lee, E.C. Galtier, E. Cunningham, G. Dyer, S. Jiang, Y Ping, A.J. Kemp, Y. Sentoku A combination of an X-ray Free Electron Laser and a high-power laser at the Matter in Extreme Conditions (MEC) at the Linac Coherent Light Source has enabled for studying the rapid changes of plasma conditions relevant to astrophysics and fusion plasmas. Because of tightly focused beams, it is challenging to simultaneously achieve beam profile characterization and data acquisition. In a pump-probe experiment at MEC, we have applied 2D monochromatic x-ray imaging to monitor the pointing of the x-ray beam and a femtosecond laser. Irradiation of a 7.0 keV x-ray beam and the laser on a solid titanium sample produced 4.5 keV K-alpha x rays, which were recorded with a spherical crystal imager. The crystal imager shows that the focusing of the x-ray beam is clearly observed but limited to a spot size of 20x40 $\mu $m$^{\mathrm{2}}$ due to heating by the x-ray beam. Details of the experiment and results of the crystal imager will be presented. [Preview Abstract] |
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B03.00006: Speeding Up Number Partitioning with Grover's Algorithm Galit Anikeeva A number of conceptually important quantum algorithms rely on the use of a black-box device known as an oracle, which is typically difficult to construct without knowing the answer to the problem that the quantum computer is intended to solve. A notable example is Grover's algorithm, which theoretically can offer a quadratic speed-up in search problems. Here we show how Grover's algorithm can be applied to a class of NP-complete decision problems---the subset sum problem and, as a special case, the number partitioning problem---in realistic experiments. Each instance of the problem is encoded in the strengths of couplings of a set of qubits to a central spin or boson, which mediates a collective phase gate consituting the quantum oracle. We propose and analyze implementations in cavity-QED and Rydberg-atom systems. [Preview Abstract] |
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