Bulletin of the American Physical Society
APS March Meeting 2017
Volume 62, Number 4
Monday–Friday, March 13–17, 2017; New Orleans, Louisiana
Session A12: Undergraduate Research/SPS IUndergraduate
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Sponsoring Units: SPS FED Chair: Cortney Bougher, American Physical Society Room: 271 |
Monday, March 13, 2017 8:00AM - 8:12AM |
A12.00001: The research on vibrating modes of Faraday waves Wending Zhao, Sihui Wang, Zhouyou Fan, Enze Chen, Huijun Zhou, Wenli Gao This paper investigates the Faraday wave patterns and corresponding vibrating modes of ideal fluid theoretically and experimentally. The dispersion relation has been got by the deriving of amplitude equations of Faraday waves. The range of eigenvalue, , is also calculated based on the parametric resonance theory. In order to predict the possible patterns in real space, we propose a geometric model on the basis of experimental parameters, which can intuitively predict the different wave patterns and the conditions of mode competitions. We also analyze the experimental phase diagram and get a good agreement between the measured and theoretical results. [Preview Abstract] |
Monday, March 13, 2017 8:12AM - 8:24AM |
A12.00002: Quantum Flows of Probability and Heat Graham Reid Open quantum systems exchange energy and information with their environment. We use a version of the method of probability currents to quantify the flow of probability between basis states in a quantum system described by a finite dimensional Hilbert space. We investigate the behavior of open systems including small thermal machines, exploring how Lindblad-type dynamical evolution gives rise to the transfer of heat, work and entropy. [Preview Abstract] |
Monday, March 13, 2017 8:24AM - 8:36AM |
A12.00003: Standard and Non-Standard Lagrangians Niyousha Davachi A concept of non-standard Lagrangians is introduced and general conditions for the existence of such Lagrangians are presented. The conditions are used to determine classes of ordinary differential equations that can be derived from non-standard Lagrangians. The obtained results are used to obtain non-standard Lagrangians for several dynamical systems of physical interest. [Preview Abstract] |
Monday, March 13, 2017 8:36AM - 8:48AM |
A12.00004: Profiling of OpenMP Parallelization in Exact Diagonalization Spencer Leeper, David Smith, Christopher Varney Exact diagonalization is an essential tool for determining the ground and excited states of quantum systems. This is particularly important for models where other techniques break down, such as the quantum Monte Carlo sign problem on frustrated magnetic systems. As the size of the Hamiltonian matrix scales exponentially with the system size, utilizing symmetries inherent in either the model or geometry is essential for block-diagonalizing the matrix to minimize the memory requirements. Subsequent improvements can be obtained using OpenMP parallelization to efficiently utilize the computational resources. Here we analyze the impact of parallelization on different aspects of the Lanczos algorithm for a two-dimensional Heisenberg model. [Preview Abstract] |
Monday, March 13, 2017 8:48AM - 9:00AM |
A12.00005: Abstract Withdrawn
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Monday, March 13, 2017 9:00AM - 9:12AM |
A12.00006: Orbital Modeling of Two-Electron Spin Qubits in Semiconductor Quantum Dots Zack White, Guy Ramon Semiconductor quantum dots (QDs) are an attractive platform for quantum computing due to their compatibility with existing microelectronic technologies. In particular, the singlet and triplet spin configurations of two electrons confined in double QDs have been considered as promising computational basis states for a robust and accessible qubit. This work develops an extended orbital model for two-electron states in double QDs that includes excited orbitals. The extended state basis is necessary to account for the dynamics of the qubit when operated under large bias, a working point accessed only recently by experiment that holds promise for better qubit performance. Our model is useful as a design tool in the analysis of decoherence mechanisms and manipulation protocols of current and new spin-based qubit devices. [Preview Abstract] |
Monday, March 13, 2017 9:12AM - 9:24AM |
A12.00007: Phase Diagram of a Quantum Ising Model with Long-Range Interactions David Smith, Spencer Leeper, Christopher Varney Advancements in utilizing ultra-cold gases as quantum spin simulators are allowing for the exploration of frustrated networks in two-dimensional spin-1/2 systems. Frustrated exchange interactions can result in exotic states and excitations, such as quantum spin liquids and spin glasses. Here we investigate the effect of long-range interactions in the quantum XXZ model on a square lattice. The complete phase diagram of the model is obtained utilizing exact diagonalization and the stability of all phases is discussed. [Preview Abstract] |
Monday, March 13, 2017 9:24AM - 9:36AM |
A12.00008: Conservation laws for waves on a string from isometries and conformal isometries of the Minkowski metric Brandon Miller, Balraj Menon Noether's theorems describe the interplay between variational symmetries (symmetries of the action functional) and local conservation laws admitted by a physical system. In Lagrangian field theories defined on a differentiable manifold $\mathcal M$ endowed with a metric $g$, the variational symmetries are intimately tied to the isometries of the metric $g$. We highlight this connection by relating the variational symmetries of waves on a string to the isometries and conformal isometries of the Minkowski metric. The associated local conservation laws and conserved quantities for this physical system are determined and their physical significance discussed. The geometric nature of these conservation laws are further elucidated by discussing their Poisson bracket formulation in the Hamiltonian framework. [Preview Abstract] |
Monday, March 13, 2017 9:36AM - 9:48AM |
A12.00009: Examining the radiation field in a star forming region Matthew Bellardini, Luke Keller We examined the propagation of photoionizing radiation in a star forming region within the Orion nebula (M42), across the barrier between ionized hydrogen and a molecular hydrogen cloud, by using infrared emissions of polycyclic aromatic hydrocarbons (PAHs). Photoionizing radiation affects the structure of the interstellar medium, how gas is heated, and how gas is ionized; this affects the physical environment and chemical structure for future star formation in the cloud. We have gathered both slit spectroscopic data and narrowband imaging data of the boundary using the FORCAST instrument on SOFIA. The spectroscopic data were taken over a wavelength range which covered three features. The imaging data were taken using three filters corresponding to the peak wavelengths of the features examined. We created and analyzed flux profiles of the features to show that the emissions peak within the boundary and decay at different rates with progression into the molecular hydrogen cloud. Our examination of the emission intensity ratio of the different features shows how photoionizing radiation propagates with spatial progression from the region of ionized hydrogen into the dense molecular cloud where gravitational collapse will eventually form new stars. [Preview Abstract] |
Monday, March 13, 2017 9:48AM - 10:00AM |
A12.00010: Relativistic effects of spacecraft with circumnavigating observer Nathaniel Shanklin, Joseph West A variation of the recently introduced Trolley Paradox, itself is a variation of the Ehrenfest Paradox is presented. In the Trolley Paradox, a ``stationary'' set of observers tracking a wheel rolling with a constant velocity find that the wheel travels further than its rest length circumference during one revolution of the wheel, despite the fact that the Lorentz contracted circumference is less than its rest value. In the variation presented, a rectangular spacecraft with onboard observers moves with constant velocity and is circumnavigated by several small ``sloops'' forming teams of inertial observers. This whole precession moves relative to a set of ``stationary'' Earth observers. Two cases are presented, one in which the sloops are evenly spaced according to the spacecraft observers, and one in which the sloops are evenly spaced according to the Earth observes. These two cases, combined with the rectangular geometry and an emphasis on what is seen by, and what is measured by, each set of observers is very helpful in sorting out the apparent contradictions. To aid in the visualizations stationary representations in excel along with animation in Visual Python and Unity are presented. The analysis presented is suitable for undergraduate physics majors. [Preview Abstract] |
Monday, March 13, 2017 10:00AM - 10:12AM |
A12.00011: Interstellar Travel Adam Rabayda, Luke Keller Interstellar space travel is a topic that is often dismissed as highly unlikely due to the vast distances involved and to considerable engineering and socioeconomic challenges. Some are left believing that it may be far from possible for us, as a species, to go anywhere beyond our solar system. We demonstrate not only the possibility of covering interstellar distances in decades or less, but also that interstellar travel is possible (in principle) with existing technology. For example: Using only special relativity and calculus, we calculated that an interstellar spacecraft could reach the Andromeda Galaxy (2.5 Million light-years from Earth) in just over 28 years at an acceleration of $9.81 \frac{m}{s}$, which would emulate Earth gravity. We also calculated that the energy required for interstellar space travel, often deemed impossible with current technology, is, in fact, possible through certain methods such as nuclear fusion. [Preview Abstract] |
Monday, March 13, 2017 10:12AM - 10:24AM |
A12.00012: Cosmic Radiation Detection and Observations Juan Ramirez Chavez, Maria Troncoso Cosmic rays consist of high-energy particles accelerated from remote supernova remnant explosions and travel vast distances throughout the universe. Upon arriving at earth, the majority of these particles ionize gases in the upper atmosphere, while others interact with gas molecules in the troposphere and producing secondary cosmic rays, which are the main focus of this research. To observe these secondary cosmic rays, a detector telescope was designed and equipped with two silicon photomultipliers (SiPMs). Each SiPM is coupled to a bundle of 4 wavelength shifting optical fibers that are embedded inside a plastic scintillator sheet. The SiPM signals were amplified using a fast preamplifier with coincidence between detectors established using a binary logic gate. The coincidence events were recorded with two devices; a digital counter and an Arduino micro-controller. For detailed analysis of the SiPM waveforms, a DRS4 sensory digitizer captured the waveforms for offline analysis with the CERN software package Physics Analysis Workstation in a Linux environment. Results from our experiments would be presented. [Preview Abstract] |
Monday, March 13, 2017 10:24AM - 10:36AM |
A12.00013: Improvement of Cosmic Radiation Detection Jose Orozco, Jose Garcia, Stefan Ritt High energy cosmic radiation constantly surges through the universe. In order to accurately analyze cosmic radiation, precise coincidence measurements need to be made. We describe experiments to identify cosmic rays using two micro photomultiplier (PMT) detectors, plastic scintillators, and green wavelength shifting optic fibers. To demonstrate the authenticity of the electrical signals produced by the micro PMT detectors, several trigger settings were implemented including double, triple and quadruple coincidences. We made extensive testing and rearrangement in our experimental setup to improve both detector signal amplitude and the number of coincidence counts collected. Our research involved three main activities: 1) separation of the micro PMT detectors to limit the arrival directions of cosmic rays 2) determining the efficiency of detecting cosmic rays at selected areas on the scintillator sheets 3) improving the efficiency with an arrangement of embedded optical fibers based on findings from activities (1) and (2) above. [Preview Abstract] |
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