Bulletin of the American Physical Society
Joint Fall 2012 Meeting of the APS New England Section and the AAPT
Volume 57, Number 15
Friday–Saturday, November 9–10, 2012; Williamtown, Massachusetts
Session E3: Quantum Physics and Plasma Physics |
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Chair: Jefferson Strait, Williams College Room: TPL 205 |
Saturday, November 10, 2012 8:00AM - 8:12AM |
E3.00001: Minimal Proofs of the Kochen-Specker theorem within the N-qubit Pauli group Mordecai Waegell, P.K. Aravind A complete class of minimal KS proofs is given for a system of N qubits. There exists a class of KS proofs using the observables of the N-qubit Pauli group, which make no direct use of rays. One particular family of these proofs, which we call ``Kites,'' is given for all N, with the N$=$2 case being the familiar Peres-Mermin Square. Each Kite generates a set of rays and bases which also prove the KS theorem. By discarding some of these rays and bases we obtain minimal KS proofs in Hilbert Spaces of all dimensions 2$^{\rm N}$. These proofs involve different numbers of projectors, but always contain just 9 measurement bases (or contexts), with Cabello's 18-9 proof for N$=$2. [Preview Abstract] |
Saturday, November 10, 2012 8:12AM - 8:24AM |
E3.00002: Semiclassical Dynamics of Charges in a Magnetic Field Christian Bracher, Alexandros Fragkopoulos Using the semiclassical method, we study the propagation of charged, monochromatic particle-waves emitted by an isotropic point source into a two-dimensional layer in the presence of crossed, homogeneous electric and magnetic fields, akin to the Hall configuration. While individual charges follow simple trochoid paths that combine cyclotron and drift motion, in combination they form intersecting trajectory fields that are characterized by intricate caustic structures and foci. Interference among these paths gives rise to strong modulations in the current emitted by the source: Depending on the energy of the charges and the electric and magnetic field strengths, the semiclassical electric flux can be strongly enhanced or completely suppressed, in accordance with quantum calculations. The associated current profile bears little resemblance to the classical trajectory pattern. Instead, we observe three distinct limiting behaviors---global suppression of particle emission, emission into discrete parallel current ``stripes,'' and closed current fields looping around the source. [Preview Abstract] |
Saturday, November 10, 2012 8:24AM - 8:36AM |
E3.00003: Nanoscale placement of germanium quantum dots on silicon surface by low dose focused ion beam templating of the substrate Maria Gherasimova, Robert Hull, Frances Ross Germanium nucleation on silicon surface typically proceeds via spontaneous formation of nanoscale islands at random locations due to the strain caused by the lattice mismatch. Due to the narrower band gap width of germanium relative to silicon, quantum confinement of charge carriers in the islands causes them to exhibit the properties of zero-dimensional quantum dots (QDs). For a variety of potential applications, such as the construction of quantum cellular automata (QCA), it is desirable to control the placement of the nucleating islands on the surface. In this work, controlled placement of Ge islands on Si substrate is achieved by templating the Si surface with focused ion beam (FIB) pulses prior to Ge growth by chemical vapor deposition in an ultra-high vacuum (UHV) environment. Ge islands are synthesized inside a transmission electron microscope equipped with a video-rate data capture capability for in situ observation, immediately after the FIB implantation in an adjacent UHV chamber. QD assembly reliability on the patterned sites is studied as the separation between the target QD locations is decreased below 100 nm, and the role of surface diffusion during growth is identified as one of the mechanisms influencing the fidelity of pattern registration. The formation of square clusters of four closely spaced islands (the arrangement of interest for the QCA) is discussed in detail as the four-fold symmetry of the (100) Si surface may provide means for obtaining the desired configuration via self-assembly. [Preview Abstract] |
Saturday, November 10, 2012 8:36AM - 8:48AM |
E3.00004: Dynamics of Dust Aggregates in a Complex Plasma Allen Davis, Jorge Carmona-Reyes, Lorin Matthews, Truell Hyde Charged dust aggregates play an important role in many astrophysical phenomena, such as early stages of protostellar and protoplanetary growth, the dynamics of planetary rings and cometary tails, and the formation of noctilucent clouds in earth's upper atmosphere. Dust is also expected to be an unwanted byproduct in the operation of plasma fusion devices, such as ITER. In all of these environments, direct study of the dust aggregates in their \textit{in situ }environment is extremely difficult, if not impossible. As a model for these complex plasma environments, dust aggregates are formed in a laboratory plasma as monodisperse spheres are accelerated in a self-excited dust density wave. Individual dust aggregates are perturbed using a diode pumped solid state laser (Coherent VERDI) with their motions recorded by a high-speed camera at 1000 fps. Analysis of the particle motion allows determination of the aggregate characteristics which determine the grain dynamics, such as charge, mass, and gas drag. [Preview Abstract] |
Saturday, November 10, 2012 8:48AM - 9:00AM |
E3.00005: Mie Resonant Absorption in Periodic Si Nanopillar Arrays Francisco Bezares, Orest Glembocki, James Long, Ronald Rendell, Richard Kasica, Loretta Shirey, Junpeng Guo, Joshua Caldwell Although Mie resonators possess characteristics that offer many advantages in the development of novel photonic devices and have been widely studied, the extent to which they interact collectively as well as the relationship between their near- and far-field properties is relatively unexplored. In this talk, we report on the results of experiments in which bright field reflectance was carried out on periodically-arrayed Si nanopillars, fabricated via electron-beam lithography, to study their collective and far-field optical properties. In addition, $\mu $-Raman scattering measurements demonstrated a clear enhancement in both the incident laser absorption and the Raman scattering from the silicon nanopillars when the incident laser line and the Mie resonance of a nanopillar were coincident. This is directly correlated to electromagnetic near-field enhancement, as a function of nanopillar diameter and array pitch. Finite Element and Finite-Difference Time Domain simulations were carried out and provide valuable insight into the nature of these dielectric resonances, the mechanism by which the Raman signal is enhanced and are in good agreement with experimental results. [Preview Abstract] |
Saturday, November 10, 2012 9:00AM - 9:12AM |
E3.00006: ABSTRACT WITHDRAWN |
Saturday, November 10, 2012 9:12AM - 9:24AM |
E3.00007: Operational Dynamic Modeling Transcending Quantum and Classical Mechanics Dmitry Zhdanov, Denys Bondar, Renan Cabrera, Herschel Rabitz We introduce a general and systematic theoretical framework for Operational Dynamic Modeling (ODM) by combining a kinematic description of a model with the evolution of the dynamical average values. The kinematics includes the algebra of the observables and their defined averages. The evolution of the average values is drawn in the form of Ehrenfest-like theorems. We show that ODM is capable of encompassing wide ranging dynamics from classical non-relativistic mechanics to quantum field theory. The generality of ODM should provide a basis for formulating novel theories. [Preview Abstract] |
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