Bulletin of the American Physical Society
46th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 60, Number 7
Monday–Friday, June 8–12, 2015; Columbus, Ohio
Session U8: Spectroscopy and Techniques |
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Sponsoring Units: GPMFC Chair: David Shiner, University of North Texas Room: Franklin CD |
(Author Not Attending)
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U8.00001: Ultra-precise measurement of the fine-structure constant by the means of atom interferometry and implementation of large-momentum-transfer beam-splitters Manuel Andia, Raphael Jannin, Clement Courvoisier, Pierre Clade, Saida Guellati-Khelifa, Francois Biraben In our experiment in Paris, we use a Ramsey-Bord\'{e} atom interferometer with cold $^{87}$Rb atoms, in combination with the technique of Bloch oscillations in an accelerated optical lattice, to measure the recoil velocity $v_r$ in $^{87}$Rb. We can then deduce the value of the fine-structure constant $\alpha$. Such an experimental scheme allows for many kinds of measurements, and in particular has led in 2013 to the proof-of-principle realization of a compact gravimeter based on Bloch oscillations, which can be used for on-board compact gravimeters or gradiometry applications. More recently, attention has been paid to the implementation of a new laser system, motivated by the need of greater laser power in order to reduce some systematic effects and to perform more Bloch oscillations, to further reduce uncertainty on $\alpha$. Upcoming projects revolve around increasing the sensitivity of the interferometer, which will be done through the Large-Momentum-Transfer Beam-Splitter technique (LMTBS). The first step towards LMTBS will be the implementation of double-diffraction, which makes the interferometer symmetrical by splitting the initial wavepacket into two opposite velocity classes. [Preview Abstract] |
Friday, June 12, 2015 10:42AM - 10:54AM |
U8.00002: Few-Nucleon Charge Radii and a Precision Isotope Shift Measurement in Helium Nima Hassan Rezaeian, David Shiner Precision atomic theory and experiment provide a valuable method to determine few nucleon charge radii, complementing the more direct scattering approaches, and providing sensitive tests of few-body nuclear theory. Some puzzles with respect to this method exist, particularly in the muonic and electronic measurements of the proton radius, and as well with respect to measurements of nuclear size in helium. We perform precision measurements of the isotope shift of the 2$^{\mathrm{3}}$S -2$^{\mathrm{3}}$P transitions in $^{\mathrm{3}}$He and $^{\mathrm{4}}$He. A tunable laser frequency discriminator and electro-optic modulation technique give precise frequency and intensity control. We select (t$_{\mathrm{s}}$ \textless 50 ms) and stabilize the intensity of the required sideband and eliminate the unused sidebands ($\le $ 10$^{\mathrm{\neg 5}})$. The technique uses a MEMS fiber switch (t$_{\mathrm{s}}=$ 10 ms) and several temperature stabilized narrow band (3 GHz) fiber gratings. A fiber based optical circulator and amplifier provide the desired isolation and net gain for the selected frequency. A beam with both species of helium is achieved using a custom fiber laser for simultaneous optical pumping. A servo-controlled retro-reflected laser beam eliminates Doppler effects. Careful detection design and software control allows for unbiased data collection. Current results will be discussed. [Preview Abstract] |
Friday, June 12, 2015 10:54AM - 11:06AM |
U8.00003: Coherent population transfer between hyperfine ground states of a $^{87}$Rb Bose-Einstein condensate by microwave-stimulated Raman adiabatic passage Sylvain Schwartz, Matthieu Dupont-Nivet, Chris Westbrook Microwave-stimulated Raman adiabatic passage (STIRAP) between internal states of a Bose-Einstein condensate (BEC) magnetically trapped in the vicinity of an atom chip is demonstrated by coherently transferring about 90 percent of a 7.000-atom BEC initially in the (F=2,mF=2) hyperfine level of the 5 2S1/2 ground state of 87Rb into (F=2,mF=1), using (F=1,mF=1) as an intermediate (unpopulated) level. The STIRAP protocol used in this experiment is robust to external perturbations as it is an adiabatic transfer, and power efficient as it involves only resonant (or quasi-resonant) processes. Taking into account the effect of losses and collisions in a Bloch equations model, we show that the maximum transfer efficiency is obtained for significantly non-zero values of the one- and two-photon detunings, which is confirmed quantitatively by our experimental measurements (and is shown to come mostly from inelastic collisions within (F=2,mF=1)). This work shows that microwave STIRAP between hyperfine ground states of magnetically trapped atoms is feasible, paving the way for STIRAP-based quantum information or metrology experiments integrated on a chip. [Preview Abstract] |
Friday, June 12, 2015 11:06AM - 11:18AM |
U8.00004: Orthogonal Polynomial Projection Quantization method applied to hydrogen atoms in large magnetic fields D. Vrinceanu Orthogonal Polynomial Projection Quantization is a method that takes advantage of the algebraic structure of the equation of power moments that can be derived for a class of Schr\"oedinger equations. One important advantage of this approach is that is able to describe well the wave function at both local and global level, which results in increased convergence rates and precision. Results for the problem of hydrogen atom in large magnetic fields are presented and compared with the state of art numerical results. [Preview Abstract] |
Friday, June 12, 2015 11:18AM - 11:30AM |
U8.00005: Constraints on exotic dipole-dipole couplings between electrons at the micron scale Shlomi Kotler, Roee Ozeri, Derek Jackson Kimball Until recently, the magnetic dipole-dipole coupling between electrons had not been directly observed experimentally. This is because at the atomic scale dipole-dipole coupling is dominated by the exchange interaction and at larger distances the dipole-dipole coupling is overwhelmed by ambient magnetic field noise. In spite of these challenges, the magnetic dipole-dipole interaction between two electron spins separated by 2.4 microns was recently measured using the valence electrons of trapped Strontium ions [S. Kotler, N. Akerman, N. Navon, Y. Glickman, and R. Ozeri, Nature {\textbf{510}}, 376 (2014)]. We have used this measurement to directly constrain exotic dipole-dipole interactions between electrons at the micron scale. For light bosons (mass $\alt$ 0.1 eV), we find that coupling constants describing pseudoscalar and axial-vector mediated interactions must be $|\frac{g_P^e g_P^e}{4 \pi \hbar c}| \leq 1.5 \times 10^{-3}$ and $|\frac{g_A^e g_A^e}{4 \pi \hbar c}| \leq 1.2 \times 10^{-17}$, respectively, at the 90\% confidence level. These bounds significantly improve on previous constraints in this mass range: for example, the constraints on axial-vector interactions are six orders of magnitude stronger than electron-positron constraints based on positronium spectroscopy. [Preview Abstract] |
Friday, June 12, 2015 11:30AM - 11:42AM |
U8.00006: Search for Violations of Bose-Einstein Statistics Using Ultra-Cold Sr Atoms Jennie Guzman, Taichi Inaki, Alexander Penaflor We are beginning an experiment to search for violations of the spin-statistics theorem (SST) for photons. Using ultracold strontium atoms, we will set constraints on the SST-forbidden two-photon transition between states with angular momentum J$=$0 and J'$=$1. In order to stimulate a transition between these two states, the pair of photons would need to possess total angular momentum J$=$1, which is an exchange-antisymmetric state forbidden by the SST. This new experimental search is motivated by enhancements to the sensitivity of possible SST violations that come from using laser-cooled strontium. These enhancements will enable an improvement in sensitivity by a few orders of magnitude compared to previous searches. [Preview Abstract] |
Friday, June 12, 2015 11:42AM - 11:54AM |
U8.00007: Experimental test of Jarzynski equality in a quasi-open quantum using a trapped ion Yao Lu, Shuoming An, Xiang Zhang, Jing-Ning Zhang, H.T. Quan, A.M. Smith, Christopher Jarzynski, Kihwan Kim We report on an experimental test of the Jarzynski equality in a quantum system consisting of a single 171Yb$+$ ion that undergoes dephasing. The Jarzynski equality, which relates equilibrium free energy differences to nonequilibrium work distributions [1], has been tested in many classical open systems and recently in isolated quantum systems [2]. For open quantum systems, however, the definitions of work and heat are not fully settled, which hinders experimental verification. Here, we study a quantum system that interacts with an environment which causes dephasing (or decoherence) without dissipation. We observe that although the work distribution varies with the strength of dephasing, the Jarzynski equality remains valid. Our investigation constitutes the first experimental test of the quantum Jarzynski equality in an effectively open quantum system. [1] C. Jarzynski, Phys. Rev. Lett. 78, 2690 (1997). [2] S. An, et al., Nature Physics, doi:10.1038/nphys3197 (2014). This work was supported by the National Basic Research Program of China under Grants No. 2011CBA00300 (No. 2011CBA00301), the National Natural Science Foundation of China under Grants No. 11374178 and 11375012, and the US National Science Foundation under Grant No. DMR 1206971. [Preview Abstract] |
Friday, June 12, 2015 11:54AM - 12:06PM |
U8.00008: Repulsive van der Waals interactions Jianing Han In this presentation, repulsive van der Waals interactions within ultracold gasses will be presented. Van der Waals interaction is generally used in physics, chemistry, biology, and other fields of science. A common misconception about van der Waals interaction is that the van der Waals interaction is attractive. This is only true for ground state atoms. For excited atoms, van der Waals interactions can be either attractive or repulsive. Since the discovery of the van der Waals interactions by Johannes Diderik van der Waals in the 1870's, it has been known as an attractive interaction. Therefore, repulsive van der Waals interaction has been rarely studied and has never been used. In this presentation, repulsive van der Waals interactions in ultracold atoms between different spins will be investigated. This study will analyze the density range for using ultracold atoms as an alternative energy source. [Preview Abstract] |
Friday, June 12, 2015 12:06PM - 12:18PM |
U8.00009: Paraxial Full-Field Cloaking Joseph Choi, John Howell Broadband, omnidirectional invisibility cloaking has been a goal of scientists since coordinate transformations were suggested for cloaking. The requirements for realizing such a cloak can be simplified by considering only the paraxial (`small-angle') regime. We recap the experimental demonstration of paraxial ray optics cloaking and theoretically complete its formalism, by extending it to the full-field of light. We then show how to build a full-field paraxial cloaking system. [Preview Abstract] |
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