Bulletin of the American Physical Society
11th Annual Meeting of the Northwest Section of APS
Volume 54, Number 6
Thursday–Saturday, May 14–16, 2009; Vancouver, BC, Canada
Session F1: Welcome and Plenary Session II |
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Chair: Michael Miller, Washington State University Room: Hennings 200 |
Saturday, May 16, 2009 8:30AM - 8:35AM |
F1.00001: Welcome and Opening Remarks
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Saturday, May 16, 2009 8:35AM - 9:11AM |
F1.00002: Searches for new physics using the neutron Invited Speaker: The decay of the neutron is one of the simplest weak decays that involve quarks. As such it can be used to search for physics beyond the standard model. In this talk I will describe recent progress in and the future outlook for improving the precision of several observables: the half life and the correlations between the neutron polarization and the momentum of the electron, the neutrino, including one that breaks the symmetry of time reversal. [Preview Abstract] |
Saturday, May 16, 2009 9:11AM - 9:47AM |
F1.00003: Finding and Characterizing Extrasolar Planets with \emph{Kepler} Invited Speaker: NASA's \emph{Kepler} spacecraft launched successfully on 2009 March 6. Its mission is to find the first rocky Earth-like planets orbiting stars other than the Sun. In particular, \emph{Kepler} will measure the frequency of rocky planets in the galaxy, determining whether our solar system is rare, typical, or something in between. I will discuss the current state of scientific knowledge about extrasolar planets, how \emph{Kepler} will contribute, and what we might learn about those planets that we find in the coming years. [Preview Abstract] |
Saturday, May 16, 2009 9:47AM - 10:23AM |
F1.00004: Controlling the Motion of Ultracold Atoms Invited Speaker: I will describe recent experimental results, where we realize an asymmetric optical potential barrier for ultracold $^{87}$Rb atoms using laser light tuned near the D$_2$ optical transition. Such a one-way barrier, where atoms impinging on one side are transmitted but reflected from the other, is a realization of Maxwell's demon and has potential implications for cooling atoms and molecules not amenable to standard laser-cooling techniques. In our experiment, atoms are confined to a far-detuned dipole trap consisting of a single focused Gaussian beam, which is divided near the focus by the barrier. The one-way barrier consists of two focused laser beams oriented almost normal to the dipole-trap axis. The first beam is tuned to present a state-dependent potential to the atoms. The second beam pumps the atoms irreversibly to the proper state on the reflecting side of the barrier, thus producing the asymmetry. We study experimentally the reflection and transmission dynamics of ultracold atoms in the presence of the one-way barrier. I will also describe our longer-term interests and efforts towards quantum measurement and control of the center-of-mass motion of atoms. [Preview Abstract] |
Saturday, May 16, 2009 10:23AM - 10:43AM |
F1.00005: BREAK
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Saturday, May 16, 2009 10:43AM - 11:19AM |
F1.00006: Inhomogeneous Fluctuating Superconductivity Near Room Temperature Invited Speaker: Over the past decade, a diverse set of experiments on high-transition temperature ($T_{c})$ cuprate superconductors have produced evidence for the existence of superconducting correlations on short time and/or length scales at temperatures well above the bulk $T_{c}$. This includes the discovery of an unusual magnetic-field induced effect in YBa$_{2}$Cu$_{3}$O$_{y}$ and La$_{2-x}$Sr$_{x}$CuO$_{4}$ above $T_{c}$ using an intense beam of spin-polarized muons at TRIUMF. The measurements show that an externally applied field induces a static internal magnetic field distribution at high temperatures far above $T_{c}$, and that the degree of field inhomogeneity is correlated with the bulk superconductivity that occurs below $T_{c}$. These findings indicate that non-uniform fluctuating superconductivity does survive in some samples at temperatures approaching room temperature. These experiments and the implications for room-temperature superconductivity will be discussed. [Preview Abstract] |
Saturday, May 16, 2009 11:19AM - 11:55AM |
F1.00007: Pattern formation in reaction-diffusion systems: From spiral waves to turbulence Invited Speaker: Almost all systems we encounter in nature possess some sort of form or structure. In many cases, the structures arise from an initially unstructured state without the action of an agent that predetermines the pattern. Such self-organized structures emerge from cooperative interactions among the constituents of the system and often exhibit properties that are distinct from those of their constituent elements or molecules. For example, chemical waves in reaction-diffusion systems are at the core of a huge variety of physical, chemical, and biological processes. In (quasi) two-dimensional situations, spiral wave patterns are especially prevalent and determine the characteristics of processes such as surface catalytic oxidation reactions, contraction of the heart muscle, and various signaling mechanisms in biological systems. In this talk, I will review and discuss recent theoretical and experimental results regarding the dynamics, properties and stability of spiral waves and their three-dimensional analog (scroll waves). Special emphasis will be given to synchronization defect lines which generically arise in complex-oscillatory media, and the phenomenon of defect-mediated turbulence or filament turbulence where the dynamics of a pattern is dominated by the rapid motion, nucleation, and annihilation of spirals or scroll waves, respectively. The latter is of direct relevance in the context of ventricular fibrillation - a turbulent electrical wave activity that destroys the coherent contraction of the ventricular muscle and its main pumping function leading to sudden cardiac death. [Preview Abstract] |
Saturday, May 16, 2009 11:55AM - 12:31PM |
F1.00008: Spin-Resolved Quantum Interference in Graphene Invited Speaker: The unusual electronic properties of single-layer graphene make it a promising material system for fundamental advances in physics, and an attractive platform for new device technologies. Graphene's spin transport properties are expected to be particularly interesting, with predictions for extremely long coherence times and intrinsic spin-polarized states at zero field. In order to test such predictions, it is necessary to measure the spin polarization of electrical currents in graphene. Here, we resolve spin transport directly from conductance features that are caused by quantum interference. These features split visibly in an in-plane magnetic field, similar to Zeeman splitting in atomic and quantum dot systems. The spin-polarized conductance features that are the subject of this work may, in the future, lead to the development of graphene devices incorporating interference-based spin filters. [Preview Abstract] |
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