Bulletin of the American Physical Society
2013 Joint Meeting of the APS Division of Atomic, Molecular & Optical Physics and the CAP Division of Atomic, Molecular & Optical Physics, Canada
Volume 58, Number 6
Monday–Friday, June 3–7, 2013; Quebec City, Canada
Session J4: Precision Measurements and Tests of Fundamental Physics II |
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Chair: Tiku Majumder, Williams College Room: 204 |
Wednesday, June 5, 2013 2:00PM - 2:12PM |
J4.00001: Progress in the Radium EDM Experiment M.R. Dietrich, K. Bailey, J.P. Greene, R.J. Holt, M.R. Kalita, W. Korsch, Z.-T. Lu, P. Mueller, T.P. O'Connor, R.H. Parker, J. Singh Ra-225 (half-life $=$ 15 d, nuclear spin $=$ 1/2) is a promising isotope for a measurement of the EDM of a diamagnetic atom or the Schiff moment of a nucleus. Due to its large nuclear octupole deformation and high atomic mass, the EDM of Ra-225 is expected to be 2-3 orders of magnitude larger than that of Hg-199. We demonstrate an efficient multiple-stage apparatus in which radium atoms are first loaded into a MOT, then loaded into a movable optical-dipole trap (ODT) that carries the atoms over 1 m of distance to a magnetically-shielded science chamber, and finally loaded into a standing-wave ODT for the measurement. We present the first observation of nuclear precession of trapped Ra-225 atoms, and discuss recent progress toward the first EDM measurement of Ra-225. This work is supported by DOE, Office of Nuclear Physics (DE-AC02-06CH11357 and DE-FG02-99ER41101). [Preview Abstract] |
Wednesday, June 5, 2013 2:12PM - 2:24PM |
J4.00002: Toward tests of QED and CPT with improved electron and positron g-factor measurements Elise Novitski, Joshua Charles Dorr, Shannon Fogwell Hoogerheide, Gerald Gabrielse We describe progress toward improved measurements of the electron and positron g-factors using quantum jump spectroscopy between the lowest quantum states of either particle trapped in a 100 mK cylindrical Penning trap. In a new apparatus---designed for improved stability and a better geometry for cavity-assisted sideband cooling---we have trapped a single electron, driven and observed single cyclotron transitions, and trapped positrons in a loading trap. This should enable measurements of both g-factors with better than the 0.28 ppt precision of the best electron value (the most precise measurement of a fundamental property of an elementary particle), thereby improving the positron value by a factor of more than 15.\footnote{D. Hanneke, S. Fogwell, and G. Gabrielse, PRL 100, 120801 (2008)}$^,$\footnote{R. S. Van Dyck, Jr., P. B. Schwinberg, and H. G. Dehmelt, PRL 59, 26 (1987)} These measurements, in combination with QED theory relating the electron g-factor to $\alpha$, will improve on the most precise determination of $\alpha$, the fine structure constant. The comparison of this value with an independent measurement of $\alpha$ is the most precise test of QED. The comparison of the e$^-$ and e$^+$ g-factors will improve upon the best test of CPT symmetry in a lepton system. [Preview Abstract] |
Wednesday, June 5, 2013 2:24PM - 2:36PM |
J4.00003: Atom counting system to measure ultra-low Kr-85 contamination in liquid xenon dark matter detectors Tae Hyun Yoon, Andre Loose, Luke Goetzke, Elena Aprile, Tanya Zelevinsky The XENON experiment aims at the direct detection of dark matter in the form of Weakly Interacting Massive Particles (WIMPs) via their elastic scattering off Xe nuclei. To achieve the required sensitivity, it is necessary to suppress Kr contamination of Xe which causes background events in Xe targets through Kr-85 beta decay. Contamination below the part per trillion level is required for the next generation targets. Magneto-optical techniques are used to cool and trap metastable Kr atoms from a RF plasma discharge. Fluorescence from single trapped Kr atoms can be detected with an avalanche photodiode (APD). The cold-atom apparatus was initially tested with Ar to avoid contamination by Kr. An estimated Kr contamination level of XENON 100 and the experimental sensitivity projections will be presented. [Preview Abstract] |
Wednesday, June 5, 2013 2:36PM - 2:48PM |
J4.00004: Highly-charged ions for atomic clocks, cosmology, and quantum information Marianna Safronova, V.A. Dzuba, V.V. Flambaum, M.G. Kozlov Despite very large ionization energies, certain ions have transitions that lie in the optical range due to level crossing and are very sensitive to $\alpha$-variation [Berengut et al., PRL105, 120801 (2011)]. Some of these systems have several long-lived metastable states representing a level structure and other properties that are not present in any neutral and low-ionization state systems and may be advantageous for the development of atomic clocks as well as provide new possibilities for quantum information storage and processing. One of the main obstacles for the experimental work in this direction is the lack of any experimental data for these systems. We carried out an exhaustive search of transitions in highly-charged ions that are particularly well suited for the experimental exploration, i.e. satisfy the following criteria: 1) existence of long-lived metastable states with transition frequencies between 170-3000~nm, 2) high sensitivity to $\alpha$-variation, and 3) existence of stable isotopes. We find that only ions in four isoelectronic sequences, Ag-like, Cd-like, In-like, and Sn-like satisfy these criteria. We use state-of-the-art theoretical approaches to provide accurate predictions for the relevant wavelengths and lifetimes and evaluate their uncertainties. [Preview Abstract] |
Wednesday, June 5, 2013 2:48PM - 3:00PM |
J4.00005: Precision Measurement of Transition Matrix Elements via Light Shift Cancellation Creston Herold, Varun Vaidya, Xiao Li, Steven Rolston, Trey Porto, Marianna Safronova We present a method for accurate determination of atomic transition matrix elements at the $10^{-3}$ level. Measurements of the ac Stark (light) shift around ``magic-zero'' wavelengths, where the light shift vanishes, provide precise constraints on the matrix elements. We make the first measurement of the 5$s$-6$p$ matrix elements in rubidium by measuring the light shift around the 421 nm and 423 nm zeros through diffraction of a Bose-Einstein condensate off a sequence of standing wave pulses. In conjunction with existing theoretical and experimental data, we find 0.3235(9) $e a_0$ and 0.5230(8) $e a_0$ for the 5$s$-6$p_{1/2}$ and 5$s$-6$p_{3/2}$ elements, respectively, an order of magnitude more accurate than the best theoretical values. This technique can provide needed, accurate matrix elements for many atoms, including those used in atomic clocks, tests of fundamental symmetries, and quantum information. [Preview Abstract] |
Wednesday, June 5, 2013 3:00PM - 3:12PM |
J4.00006: Quantum Logic Enabled Test of Discrete Symmetries Timko Dubielzig, Malte Niemann, Anna-Greta Paschke, Martina Carsjens, Matthias Kohnen, Christian Ospelkaus Much progress has been made recently towards a CPT test with baryons based on the (anti-)proton's magnetic moment [1, 2]. A big challenge in any such experiment is the spin state measurement for single (anti-)protons, which has not been realized yet at the single-shot level, as would be desirable for an accurate and competitive g-factor CPT test. We describe concepts and simulations for an experiment which will implement single-shot fast readout using quantum logic operations according to the proposal by Heinzen and Wineland [3]. We discuss trapping geometries, concepts for single (anti-)proton rf sideband control, and for ground state cooling of the atomic quantum logic ion at fields exceeding 1 Tesla in a miniaturized Penning trap.\\[4pt] [1] S.Ulmer et al., Phys. Rev. Let. 106, 253001 (2011)\\[0pt] [2] N. Guise et al., Phys. Rev. Let. 104, 143001 (2010)\\[0pt] [3] Heinzen and Wineland, PRA 42, 2977 (1990) [Preview Abstract] |
Wednesday, June 5, 2013 3:12PM - 3:24PM |
J4.00007: Role of GNOME in dark-matter searches Szymon Pustelny, Maxim Pospelov, Micah P. Ledbetter, Derek F. Jackson Kimball, Wojciech Gawlik, Dmitry Budker, Przemyslaw Wlodarczyk, Joshua Smith, Jocelyn Read, Chris Pankow We present a novel scheme for exotic-interaction searches. The scheme enables detection of short-time interaction between spins and other objects, whose signatures in traditional studies are buried in noise or cannot be singled out from instrumental artifacts. These short signals may, for example, arise, when spins interact with a jet of exotic particles or go through a non-uniform scalar field. It is shown that their detection is possible with synchronous measurements of readouts of at least five spatially separated devices, whose readouts are correlated. The application of a new scheme is demonstrated based on an example of Global Network of Optical Magnetometers for Exotic physics (GNOME). [Preview Abstract] |
Wednesday, June 5, 2013 3:24PM - 3:36PM |
J4.00008: Renormalized Perturbative Corrections to Casimir Energies due to the Roughness of aDielectric Plate and Finite Temperature -- an Effective Field Theory Approach Martin Schaden, Hua-Yao Wu We present a systematic perturbative approach to the interaction of the electromagnetic field with stochastically rough surfaces. Spurious perturbative short wavelength contributions are renormalized by modeling the scattering matrix for long wavelengths. Scattering off a rough plate at long (transverse) wavelengths is described by scattering off an effectively flat plate with the inclusion of the plasmon correction. Any roughness profile$h(x_{\bot } )$ with standard deviation small compared to the wavelength of the electromagnetic radiation may be considered and in particular roughness profiles with a correlation, such as$\left\langle {h(x_{\bot } )h(y_{\bot } )} \right\rangle =\sigma^{2}\exp (-{\vert x_{\bot } -y_{\bot } \vert } \mathord{\left/ {\vphantom {{\vert x_{\bot } -y_{\bot } \vert } \ell }} \right. \kern-\nulldelimiterspace} \ell )$, with a finite derivative at the origin. These would lead to a divergent scattering matrix in a conventional (un-renormalized) perturbative approach. We obtain perturbative roughness corrections to the Casimir energy of dielectric plates at finite temperature using Drude- and plasma- models for the dielectric permittivity. Up to a shift in the effective separation, the Casimir energy between a rough and a flat plate for decreasing correlation length approaches that between two flat plates - in agreement with intuition and non-perturbative results for corrugated plates. Our perturbative calculation reproduces exact calculations for a plate with one-dimensional periodic corrugation in the limit$\sigma \ll a$. These results are used to estimate roughness corrections to precision Casimir measurements. [Preview Abstract] |
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