Bulletin of the American Physical Society
Annual Meeting of the APS Four Corners Section
Volume 62, Number 17
Friday–Saturday, October 20–21, 2017; Fort Collins, CO
Session C1: Atomic, Molecular and Optical Physics I |
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Chair: Charles Durfee, Colorado School of Mines Room: Lory Student Center 382 |
Friday, October 20, 2017 10:30AM - 10:54AM |
C1.00001: Two-photon cooling of atomic hydrogen Invited Speaker: Dylan Yost Since 2010, determinations of the proton charge radius through spectroscopic comparisons of hydrogen and muonic hydrogen (a bound state of a muon and a proton) have been inconsistent. As a result, it is anticipated that the current set of hydrogen data may contain unknown or poorly controlled systematic effects. Therefore, there is a need for additional hydrogen data using new experimental techniques. Since most systematic effects in hydrogen spectroscopy can be traced back to the finite temperature of the atoms, I will discuss our plans to implement a two-photon laser cooling technique for hydrogen. This technique could reduce the temperature of a hydrogen sample to near the recoil limit of $\sim$1 mK. Spectroscopy of this cold, and possibly trapped atomic sample would likely allow us to better understand the proton radius puzzle. In addition, I will discuss our plans to measure the hydrogen 2S-8D transition in a new apparatus using optical preparation of the 2S state. This measurement will first be attempted with a cryogenic (4K) source of atomic hydrogen. [Preview Abstract] |
Friday, October 20, 2017 10:54AM - 11:06AM |
C1.00002: Near-resonant light focusing and refraction in an elongated ultracold atom gas Jonathan Gilbert, Colin Roberts, Jacob Roberts The density variation of atoms in a trapped ultracold atomic gas leads to a spatial variation of the index of refraction in the gas for near-resonant light. For commonly-realized experimental situations where light propagates along the axis of an elongated trapped atom gas, this index variation can lead to substantial focusing or defocusing of light propagating along the long direction of the gas. Remarkably, increases in light intensity by more than an order of magnitude above the incident intensity are predicted to occur in nominally optically thick gases where the absorption length is much smaller than the spatial extent of the gas. We will present calculations of the propagation of light in these situations as well as present the experimental observations that prompted us to examine the physics of this light propagation in more detail. [Preview Abstract] |
Friday, October 20, 2017 11:06AM - 11:18AM |
C1.00003: Dynamics of dark-bright vector solitons in Bose-Einstein condensates Majed O. D. A. Alotaibi, Lincoln D. Carr We analyze the dynamics of two-component vector solitons, namely dark-bright solitons, via the variational approximation in Bose-Einstein condensates. The system is described by a vector nonlinear Schrodinger equation appropriate to multi-component Bose-Einstein condensates. The variational approximation is based on a hyperbolic tangent (hyperbolic secant) for the dark (bright) component, which leads to a system of coupled ordinary differential equations for the evolution of the ansatz parameters. We obtain the oscillation dynamics of two-component dark-bright solitons. Analytical calculations are performed for same-width components in the vector soliton and numerical calculations extend the results to arbitrary widths. We calculate the binding energy of the system and find it proportional to the intercomponent coupling interaction, and numerically demonstrate the break up or unbinding of a dark-bright soliton. Our calculations explore observable eigenmodes, namely the internal oscillation eigenmode and the Goldstone eigenmode. [Preview Abstract] |
Friday, October 20, 2017 11:18AM - 11:30AM |
C1.00004: Cold Hydroxyl Radicals David Reens, Hao Wu, Tim Langen, Jun Ye With the goal of studying hydroxyl radicals in the ultracold regime typically attained with alkali atoms, we are pursuing evaporative cooling of a 50 mK trapped sample decelerated from a molecular beam. Along the way we have identified and mitigated an unusual trap loss process relating to the internal dynamics of the molecules in external electric and magnetic fields. We are also working at the forefront of molecular beam technology in order to maximize the initial density of the trapped sample for successful evaporation, and we hope to bring a new system online at the end of this year. [Preview Abstract] |
Friday, October 20, 2017 11:30AM - 11:42AM |
C1.00005: Laser cooling and Zeeman slowing of a silicon atomic beam Sam Ronald, William Fairbank, Siu Au Lee We are attempting to cool and trap a single atom of silicon in a magneto-optical trap to be used as a highly controlled source for an ion beam. The ultimate goal is the deterministic implantation of single silicon atoms in an array in a silicon chip to be used as a set of qubits in a quantum computer. Our silicon is generated in an atomic beam at a relatively high temperature. In order to have an appreciable number of trappable atoms, we use a variable pitch Zeeman slower to precool this beam. Zeeman slowers are used to cool atomic beams by creating a varying magnetic field to match the deceleration of atoms with a certain entrance velocity. To address the $^{3}$P$_{2}$ to $^{3}$D$_{2}$ transition at 221.7nm, we utilize a frequency quadrupled CW laser. When the cooling laser is used simultaneously as a probe of the velocity distribution changes, interesting features have been observed which allow us to evaluate the performance of the slower. In this talk, I will describe the construction of the slower, the analysis techniques used, and evaluate the performance of our Zeeman slower, as well as discuss how they will impact future developments for the project. [Preview Abstract] |
Friday, October 20, 2017 11:42AM - 11:54AM |
C1.00006: Development of a technique for imaging single Ba atoms in solid xenon by laser scanning Danielle Harris, Chris Chambers, David Fairbank, James Todd, Tim Walton, William Fairbank Jr. We are developing a method of barium tagging for the nEXO double beta decay experiment that may allow for elimination of all backgrounds except a very small contribution from two-neutrino double beta decay. In this method, a barium ion is frozen with some surrounding xenon on a cold probe that is inserted into LXe. This ion, or atom if it is neutralized, is then detected by matrix isolation spectroscopy in the solid xenon matrix on the probe. We have imaged single barium atoms in a solid xenon matrix using a fixed laser technique and are modifying our experimental set up to instead scan an area for a single barium ion. Progress on single barium atom imaging using a scanning technique will be reported. [Preview Abstract] |
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