Bulletin of the American Physical Society
2018 Annual Meeting of the APS Four Corners Section
Volume 63, Number 16
Friday–Saturday, October 12–13, 2018; University of Utah, Salt Lake City, Utah
Session L05: AMO4: Optical Trapping and Precision Measurements |
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Chair: Dallin Durfee, Brigham Young University Room: CSC 208 |
Saturday, October 13, 2018 11:20AM - 11:44AM |
L05.00001: Measuring and quantifying quantum memory effects in cold atom systems Invited Speaker: Chen-Yen Lai Classical memory effects are observable in many systems which are history-dependent, including magnetization and rechargeable batteries, and also have broad applications. On the other hand, the quantum memory effects are also observable in atomic superfluids. Although memory effects exist in quantum systems, some dynamical variables such as steady state current or particle density do not reveal the quantum memory quantitatively. Here, we present three different examples to elaborate on how to quantify quantum memory effects in cold atom systems. First, we consider non-interacting fermions loaded in a ring shape potential. Applying an artificial gauge drives a current and considering the dissipation from the background, the current versus driving forms a hysteresis loop as the current lags behind due to dissipation. The second example, non-interacting particles are loaded in a tunable optical lattice which transforms from triangular to kagome geometry. Since there is a flat band in kagome lattices, the steady state particle density depends on the rate of lattice transformation. In the final example, we show systems undergo interaction imbalance with different ramping timescales and the steady state current exhibits memory of the ramping time for both fermionic and bosonic systems. The memory effects of dynamical variables in cold atoms provide promising applications in atomtronics. |
Saturday, October 13, 2018 11:44AM - 11:56AM |
L05.00002: Proposal for loading hydrogen into a magic wavelength optical lattice Zakary Burkley, Dylan C Yost We propose a method for loading hydrogen into a magic wavelength optical lattice. We first consider hydrogen atoms from a cryogenic atomic beam which interact with 243 nm radiation as they pass through an optical lattice potential. We find that only a single scattering event on the 1S-2S transition can remove enough kinetic energy to trap hydrogen in the lattice. To model this, we use a Monte Carlo method to simulate atomic trajectories and the stochastic nature of spontaneous absorption and emission. We also investigate techniques to mitigate photoionization losses and determine the total number of hydrogen atoms we can load into the optical lattice within a given loading period. |
Saturday, October 13, 2018 11:56AM - 12:08PM |
L05.00003: Levitating Microscopic Particles in a Laser Beam via Photophoresis Leslie Howe Within the focus of a laser beam, microscopic particles surrounded by air can become trapped by the heating of the particle and the resulting interaction with surrounding air molecules. This photophoretic effect can withstand wind speeds up to 2 meters per second, and thus centimeter-scale patterns can be drawn in mid air by utilizing the strong light scattered from the particle while sweeping the laser beam through space. Motivating the study of this effect is the desire to increase the potential sweep speed of a laser to create larger and more intricate patterns. While it is known that structure in the laser beam, such as that arising from spherical aberration, aids in stable trapping, questions remain as to exactly how a particle becomes stably trapped in a particular beam location, as particles exhibit oscillations or excursions over tens of microns and accelerations up to 10 gs. |
Saturday, October 13, 2018 12:08PM - 12:20PM |
L05.00004: Precision Measurement of the 6S-7P1/2 Cesium Transition Radial Matrix Element via Simultaneous Absorption Spectroscopy Eric Ryan Putney, George Toh, Amy Damitz, Daniel Elliott Parity non-conservation in cesium electronic transitions has gathered significant interest over the past several decades, providing opportunities to probe the strength of the weak interaction. Through precise absorption strength measurements of classically permitted cesium transitions (6S-7P1/2, 6S-7P3/2) the strength of the classically forbidden parity non-conserving 6S-7S transition may be better understood. This measurement aims to refine the known strength of the 6S-7P1/2 transition through simultaneous absorption strength measurements of both the 6S-7P1/2 and 6S-7P3/2 transitions. When these measurements are made simultaneously, the precise calculation of a radial matrix element is possible when the other radial matrix element is already precisely known. This methodology eliminates the need for knowledge of traditionally necessary parameters such as the density of the cesium cell and its length. Such parameters are difficult to determine experimentally. While work to verify our result continues, we have measured the ratio to better than 0.1% precision, more than 5 times better than past measurements. |
Saturday, October 13, 2018 12:20PM - 12:32PM |
L05.00005: Stabilizing Lasers by Analyzing Phase Noise Paige Price, Dallin S. Durfee, Jarom S. Jackson External cavity diode lasers mode hop unexpectedly and often. Based on previous measurements by others in the field, we have theorized that a substantial amount of phase noise occurs when a laser is about to switch modes. We are creating a system which monitors phase noise and makes the necessary adjustments to maintain laser stability. |
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