Bulletin of the American Physical Society
2008 Joint Fall Meeting of the Texas and Four Corners Sections of APS, AAPT, and Zones 13 and 16 of SPS, and the Societies of Hispanic & Black Physicists
Volume 53, Number 11
Friday–Saturday, October 17–18, 2008; El Paso, Texas
Session J6: General Physics |
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Chair: Jean-Francois Van Huele, Brigham Young University Room: Union East, 3rd Floor Wiggins |
Saturday, October 18, 2008 1:30PM - 1:42PM |
J6.00001: Constructing quantum localization operators using conformal symmetry Lucas Earl, Jean-Francois Van Huele We review the difficulties in merging quantum theory with relativity. In particular, we discuss the issue of localization in quantum mechanics. We introduce the conformal group, a supergroup of the Poincar\'{e} group and give its generators and the corresponding algebra. We then illustrate how this allows us to create a space-time localization operator that is consistent with special relativity and quantum theory. We give an explicit expression of the localization operators in 1+1 dimensions and discuss the challenges of generalizing it to higher dimensions. [Preview Abstract] |
Saturday, October 18, 2008 1:42PM - 1:54PM |
J6.00002: Application of Generalized Hamiltonian Dynamics to Modified Coulomb Potential Julian Antolin Camarena, Eugene Oks We apply Dirac's generalized Hamiltonian dynamics (GHD), a purely classical formalism, to spinless particles under the influence of a binomial potential. The integrals of the motion for this potential were chosen as the constraints of GHD, and use Fradkin's unit Runge vector in place of the Laplace-Runge-Lenz vector. A functional form of the unit Runge vector is derived for the binomial potential. It is shown in accordance with Oks and Uzer (2002) that a new kind of time dilation occurs for stable, nonradiating states. The primary result which is derived is that the energy of these classical stable states agrees exactly with the quantal results for the ground state and all states of odd values of the radial and angular harmonic numbers. [Preview Abstract] |
Saturday, October 18, 2008 1:54PM - 2:06PM |
J6.00003: Computing Energies and Properties of Small Molecules Using Fully Nonadiabatic Wavefunctions Steve Alexander, R.L. Coldwell Using variational Monte Carlo methods and compact, explicitly-correlated fully nonadiabatic wavefunctions we have computed the energies and properties of several rovibrational states for several small molecules. We have extensively examined the form of the wavefunctions that are needed to accurately describe the excited vibrational and rotational states of these systems. Examples of each form will be discussed. Our results will be compared with previous calculations and we will show that the accuracy of this method is similar to comparable Born-Oppenheimer calculations. [Preview Abstract] |
Saturday, October 18, 2008 2:06PM - 2:18PM |
J6.00004: Efficiency of Accelerator Driven Thermal Thorium Nuclear Reactors M.A.K. Lodhi, Mike Shubov We consider Accelerator Driven Thermal Thorium Reactors (ADTTNR) both for production of energy and isotopes This study indicates that such system can produce 2-15 times the energy, its accelerator consumes. The energy gain depends on the speed with which it burns fuel. A slow reactor, which burns 0.9\% of thorium per year, and has a neutron loss of 4\% would have an electrical efficiency 70-79\%. (Neutron loss is the proportion of neutrons absorbed by reactor itself rather than material within it.) The wide range in reactor efficiency is due to the uncertainty in the number of neutrons produced per GeV accelerator energy. This system is expected also to be safer, then reactors currently in use. [Preview Abstract] |
Saturday, October 18, 2008 2:18PM - 2:30PM |
J6.00005: Effective electromagnetic operators in the p-shell using the No-Core Shell Model formalism Michael Kruse, Alexander Lisetskiy, Bruce Barrett, Petr Navr\'atil, Ionel Stetcu, James Vary Much effort has been devoted to creating Standard Shell Model (SSM) effective interactions from ab initio techniques such as the No-Core Shell Model (NCSM). Such a procedure drastically reduces the computational effort necessary to find the low-lying states of a light nucleus ($A\leq14$) and in most cases the results agree quite well with experiments. One can also create a similar SSM effective operator for an electromagnetic operator, like E2 and M1. The properties of such operators, for example in terms of renormalization of proton and neutron charges as a function of model space size are not clearly understood. We present a procedure for creating E2 and M1 operators in the p- shell, using $^5$Li, $^5$He and $^6$Li, and show how these operators depend on one- and two-body contributions. This is particularly interesting for long-range operators such as E2. [Preview Abstract] |
Saturday, October 18, 2008 2:30PM - 2:42PM |
J6.00006: Pion-Pion Scattering in the Rho Meson Region Regina Azevedo, Ubirajara van Kolck The pion-pion elastic scattering cross-section has a bump around the center-of-mass energy $E= (770 \pm 3)$ MeV, the rho meson region. Chiral Perturbation Theory (ChPT) describes pion-pion scattering well at lower energies but fails to explain this bump. We generalize ChPT by including the rho meson in an Effective Field Theory with a systematic power counting. We have used a realization of chiral $SU(2)_L \times SU(2)_R$ symmetry (``vector realization'') that includes not only massless pseudoscalar mesons (pions) but also scalars that become the longitudinal components of the vector mesons (rhos). We apply the power counting to pion-pion scattering around the bump. In leading order only the P wave with isospin $I=1$ contributes. We have calculated the corresponding phase shifts, which depend on a single parameter. I will present the results of a fitting to data and discuss the extension to higher orders. [Preview Abstract] |
Saturday, October 18, 2008 2:42PM - 2:54PM |
J6.00007: Selectively Grown Silicon Nano-Wires for Transistor Devices Jon Brame, Nathan Woods The goal of this project is to fabricate a transistor device using silicon nano-wires (SiNW) as semiconductors. In order to be able to establish electrical conduct with the nano-wires the SiNW growth is confined to certain areas that can be contacted using electron-beam lithography (EBL). This is done by controlling the catalyst deposition through angle-evaporation onto pillars on the device. The nanowires then grow from the sidewalls of the pillars and can be contacted using EBL. [Preview Abstract] |
Saturday, October 18, 2008 2:54PM - 3:06PM |
J6.00008: Nanoscale Electric Field Sensor-Development and Testing Jon Brame, Nathan Woods The goal of this project is to test a carbon nanotube based electric field sensing device. The device consists of a miniature gold needle suspended on a mat of carbon nanotubes over a trench on a Si/Si02 substrate. Field tests were made by recording the electric field inside dust devils in a Nevada desert, and those electric fields were simulated in a lab environment. Further tests to determine the device sensitivity were performed by manually manipulating the gold needle with an Atomic Force Microscope (AFM) tip. We report on fabrication techniques, field and lab test results and AFM testing results. [Preview Abstract] |
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