Bulletin of the American Physical Society
2019 Annual Fall Meeting of the APS New England Section
Volume 64, Number 21
Friday–Saturday, October 11–12, 2019; Warwick, Rhode Island
Session D01: Atomic & Quantum Physics |
Hide Abstracts |
Chair: Richard Price, Massachusetts Institute of Technology Room: Knight Campus CCRI 4090 |
Saturday, October 12, 2019 10:30AM - 10:42AM |
D01.00001: Engineering of entanglement in semiconductor nanowires Dung Pham, Sathwik Bharadwaj, L. R. Ram-Mohan Confined geometries such as semiconductor quantum wires and quantum dots are promising candidates for fabricating quantum computing devices. When several quantum dots are in proximity, spatial correlation between electrons in the system becomes significant, and leads to spatial entanglement. Spatial entanglement values can be tuned with external parameters, and this provides a new avenue for forming quantum bits. Here we examine the entanglement properties of two electrons in quantum dots formed inside GaAs/Ga$_x$Al$_{1−x}$As superlattice wires. We develop a fully variational formulation for calculating accurate few-electron wavefunctions in configuration space, and we use it to investigate the dependence of spatial entanglement on various geometrical parameters. Resonant behaviors associated with crossings of states are studied for the first time. We also observe the formation of electron clusters, and show that the entanglement value is a good indicator for the formation/dissolution of such clusters. Further, we show that a precise manipulation of the entanglement values is feasible with applied electric and magnetic fields. [Preview Abstract] |
Saturday, October 12, 2019 10:42AM - 10:54AM |
D01.00002: Study of Carbon Isotopic Effects in Hydrocarbon Chains Zhe Kan, Wangyao Li, Mengyan Shen 13C has been a reliable candidate as an isotopic tracer in various research areas, such as chemical reactions, metabolic pathways, and molecule labeling. However, carbon isotope selectivity has been reported in recent hydrocarbon synthesis experiments by using the cobalt catalyzed Fischer-Tropsch method. Here, we present a theoretical study of the carbon isotopic effects in hydrocarbon chains. The theoretical methods include a Huckel-tight binding model, a configuration analysis, and quantum state perturbation theory. The electron vibrational energy in free 13C atoms differs from that in free 12C atoms and it is implemented in the Hamiltonian of each carbon atom ab-initially. Using the same amount of free 12C and 13C atoms provided as reactants, a possible configuration of mixed species bonded chains is analyzed in comparison with a configuration of the same species bonded chains. According to the calculations of these two configurations, noticeable differences in electron band structures and electron distributions are found. Moreover, the probability of converting free 12C and 13C atoms into a certain configuration of bonded chains is estimated through the methodology of quantum perturbation. The configuration involving only pure 12C chains and 13C chains is found to have the greatest possibility over any other configuration with mixed species bonded chains. It indicates that the same species tend to group together upon forming a hydrocarbon chain, this is in contradiction with a mechanism of random selection. This finding can provide a prediction and explanation of isotope selectivity in certain hydrocarbon synthesis experiments. [Preview Abstract] |
Saturday, October 12, 2019 10:54AM - 11:06AM |
D01.00003: Revisiting Lorentz Transformations with Quaternions Douglas Sweetser Minkowski recognized that special relativity could be viewed as a rotation in a 4D vector space. Unit quaternions (the compact Lie group SU(2)) are a double cover for 3D rotations, SO(3). It was long claimed that representing the non-compact Lorentz group SO(3, 1) with quaternions could not be done. In 2010 I found a way to generalize a rotation to do Lorentz boosts (Dr. Kharinov discovered independently): $$ B \rightarrow B' = h B h^* + \frac{1}{2}((h h B)^* - (h^* h^* B)^*) $$ If $h = (\cosh(x), I \sinh(x)) $, this do a Lorentz boost. In 2013 I noticed that for a quaternion cross product normalized to one, the scalar term is zero and the second and third terms cancel leaving the 3D rotation. Physics cannot be done with space-time alone. Space-time is a base space and an affine space, energy-momentum. Three rotations live in space-time, three velocities in energy-momentum. View the quaternion scalar as time and the 3-vector as space, so animations of SU(2) and SO(3, 1) can be created. SU(2) starts as a point, specifically t=-1 at the spatial origin. It grows to its maximum size at time-now, t=0. The sphere shrinks to zero size at t=1. The animation for SO(3, 1) starts out infinitely huge, shrinks to its smallest size at t=0 matching SU(2) before expanding to infinity. [Preview Abstract] |
Saturday, October 12, 2019 11:06AM - 11:18AM |
D01.00004: High spin intruder states of $^{44}$Ca and $^{45}$Ca using fusion evaporation reactions Andrew MacGregor, Peter DeRosa, Dan Foulds-Holt, Peter Bender Identifying collective states with clear n-particle-n-hole structure near closed shells can reveal deformation driving orbital characteristics. Such states, often high-spin in nature, can be populated using the fusion-evaporation reaction mechanism, extracted using gamma-ray spectroscopy techniques and compared to state-of-the-art theoretical shell model calculations. Recently, an experiment to look for intruder states in $^{44,45}$Ca was done using the $^{36}$S$(^{14}$C$,p)$ and $^{36}$S$(^{14}$C,$pn)$ reactions at 34-MeV performed at Florida State University's John D. Fox superconducting Laboratory. The experimental setup included an array of HPGe detectors surrounding the enriched $^{36}$S as well as a Si particle detector telescope located at zero-degrees with respect to the beam axis. The telescope has allowed specific reaction residue to be correlated with observed $\gamma$-rays. We present preliminary results from the experiment. [Preview Abstract] |
(Author Not Attending)
|
D01.00005: Application of Artificial Intelligence in Tuning Femtosecond Laser Systems Vlad Gaciu This work describes a design used to automate a tunable laser system to correctly and autonomously reach user requested peak wavelengths and spectral widths. This laser system is comprised of a tunable mode-locked femtosecond laser. The system is tunable by mechanical motors programmable with software. Varying slit width and slit position shift the peak in opposite directions, which allows a secondary tuning of the spectral width, which is only dependent on the slit width. The automation displays a level of artificial intelligence where the program acquires data autonomously and applies machine learning techniques to predict and understand a suitable slit position and slit width for any desired output. This design does not require an experienced user and can significantly save time. Future developments with the current design can be made to automate larger and more complicated tunable laser systems. This is a new area of research which can help pave the way for more advanced use in the ultrafast laser industry. [Preview Abstract] |
Saturday, October 12, 2019 11:30AM - 11:42AM |
D01.00006: The Double Slit Experiment Viewed as an Unsolved Math Problem. Jeffrey Boyd If the double slit experiment were an unsolved math problem, an applied mathematician might devise an fortuitous plan of attack. This APS member is such a mathematician. Searching for ignored peculiarities, we discover empirical evidence that sometimes particles follow zero energy waves backwards. This is counterintuitive, and we will postpone addressing how that is possible. What if there were such waves involved in a double slit experiment. Every point on the target screen would emanate waves, they would go through the two slits and interfere at the particle gun. At random, and based on the strength of the interference, a particle would choose one particular wave to follow backwards. After that the mechanism would become deterministic, with no further wave interference. The particle would follow its wave with a probability of one and make a dot at that point where its wave originated. It is easily proved that this would reproduce the mathematics and the pattern on the target screen. If we take a wave described by Feynman, and turn it around, we would have a model for the wave we seek. It is easily shown that the amplitudes of these waves form a linear vector Hilbert space. It is easily shown that these could be Schroedinger waves. Schroedinger waves have zero energy; they carry probability amplitudes instead. Three new axioms arise: 1. Wave function collapse occurs before measurement; 2. there is no wave particle duality; 3. Waves and particles travel in opposite directions. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700