Bulletin of the American Physical Society
42nd Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 56, Number 5
Monday–Friday, June 13–17, 2011; Atlanta, Georgia
Session K2: Fundamental Symmetries and Precision Measurements |
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Sponsoring Units: GPMFC Chair: Zheng-Tian Lu, Argonne National Laboratory Room: A602 |
Wednesday, June 15, 2011 2:00PM - 2:12PM |
K2.00001: Recent Results from the PbO* Electron EDM Experiment Paul Hamilton, Stephen Eckel, Emil Kirilov, Hunter Smith, David DeMille Observation of an electric dipole moment (EDM) of the electron would imply new physics with CP violation beyond the Standard Model. A new generation of experiments propose to take advantage of the enhanced sensitivity of polar molecules to an electron EDM due to their enormous effective internal electric fields ($>$10 GV/cm). In addition, molecular states which exhibit parity doubling can be used to effectively reverse the direction of the internal electric field without changing external fields applied to the molecules. This novel experimental control leads to an enormous suppression of the systematic effects most common to EDM experiments. Our experiment uses a high temperature vapor cell containing PbO. The large vapor density leads to a higher counting rate than traditional beam experiments. Recent improvements to the experimental apparatus and new analysis techniques have now increased our optimal statistical sensitivity to better than $10^{-27} e\cdot cm/\surd$day, potentially allowing for an improved limit on the electron EDM in a few days integration time. e will discuss these improvements as well as preliminary results and investigations of systematic effects. [Preview Abstract] |
Wednesday, June 15, 2011 2:12PM - 2:24PM |
K2.00002: Spectroscopic Characterization of Thorium Monoxide for use in an Electron Electric Dipole Momement Measurement Paul Hess, Yulia Gurevich, Nick Hutzler, Elizabeth Petrik, Benjamin Spaun, John Doyle, Gerald Gabrielse, Emil Kirilov, Amar Vutha, David DeMille The ACME Collaboration is searching for the electron electric dipole moment (eEDM) in the metastable H $^3\Delta_1$ state of thorium monoxide (ThO) using a cryogenic molecular beam.\footnote{A.C.~Vutha \textit{et al.}, Phys. B 43, 074007 (2010)} The primary molecular beam source has been fully characterized and optimized.\footnote{N.R.~Hutzler \textit{et al.}, arXiv:1101.4217 (2011)} We report on advances in characterizing the spectroscopic properties of the ThO molecule. Transitions necessary for H state preparation and detection have been observed for the the first time, and the saturation parameters for these transitions have been measured. The electric polarizability of the H state and its small g-factor have been measured. The lifetime of a key excited state has been measured. We also report on preliminary results on state preparation and readout of coherent precession phases. [Preview Abstract] |
Wednesday, June 15, 2011 2:24PM - 2:36PM |
K2.00003: Progress towards an electron EDM search using hafnium fluoride ions Huanqian Loh, Matt Grau, Tyler Yahn, Robert Field, Eric Cornell Trapped molecular ions provide large effective electric fields and long electron spin coherence times for the search for an electron electric dipole moment (eEDM). In particular, the $^3\Delta_1$ state of HfF$^+$ has been proposed as a candidate for the eEDM search. To create HfF$^+$, we optically excite a supersonic beam of neutral HfF with two photons to an autoionizing state, and then perform laser-induced fluorescence to detect the state of the resultant HfF$^+$ ions. We report on our efforts to understand the autoionization process for efficient state preparation of HfF$^+$ ions, and on our general progress towards an eEDM measurement. This work is funded by the US National Science Foundation. [Preview Abstract] |
Wednesday, June 15, 2011 2:36PM - 2:48PM |
K2.00004: Manipulation of Ultracold Radium Atoms for a Nuclear EDM Measurement M.R. Dietrich, K. Bailey, J.P. Greene, R.J. Holt, M. Kalita, W. Korsch, Z.-T. Lu, P. Mueller, R.H. Parker, J. Singh, I.A. Sulai, T.P. O'Connor We describe recent progress towards measurement of the nuclear electric dipole moment (EDM) of radium. Neutral ultracold radium is loaded from a magneto-optic trap into an optical dipole trap (ODT), which is mechanically translated to move the radium into the science region. Here the atoms are observed and transferred into a second ODT suitable for EDM measurements. Short and long term prospects for upcoming permanent EDM measurements are discussed. Research supported by DOE, Office of Nuclear Physics, under contract DE-AC02-06CH11357. [Preview Abstract] |
Wednesday, June 15, 2011 2:48PM - 3:00PM |
K2.00005: Status of the University of Oklahoma Search for the Signature of an e-EDM in the Interaction of the PbF Molecule with an Electric Field N.E. Shafer-Ray This talk presents an update of an ongoing effort at the University of Oklahoma to measure the electric dipole moment of the electron (e-EDM) by studying the interaction of a molecular beam of $^{208}$Pb$^{19}$F molecules with an external electric field. [Preview Abstract] |
Wednesday, June 15, 2011 3:00PM - 3:12PM |
K2.00006: Precision Spectroscopy of Trapped Radium Ions G.S. Giri, J.E. van den Berg, D.J. van der Hoek, S. Hoekstra, K. Jungmann, W. Kruithof, M. Nunez-Portela, C.J.G. Onderwater, B. Santra, R.G.E. Timmermans, O.O. Versolato, L.W. Wansbeek, L. Willmann, H.W. Wilschut A single trapped radium ion is an ideal candidate for high precision experiments. Atomic parity violation can be measured in a single Ra$^+$, enabling a precise measurement of the electroweak mixing angle (Weinberg angle) in the Standard Model of particle physics. The Weinberg angle can be measured via a determination of the light shift in the forbidden 7$^2$S$_{1/2}$-6$^2$D$_{3/2}$ transition in a single trapped Ra$^+$. In this alkali like system the sensitivity to parity violating weak interaction effects is 50 times higher than that in Cs, where the best such experiments were performed to date. We have succeeded in the production of a series of short lived radium isotopes. The isotopes produced were stopped and thermalized to Ra$^+$ in a Thermal Ionizer, mass separated in a Wien filter, gas-cooled in a Radio Frequency Quadrupole and subsequently trapped as a cloud in a linear Paul trap. Laser spectroscopy of the trapped radium ions has been performed. The results on hyperfine structures, isotope shifts and lifetimes are important input to test the accuracy of atomic theory, the precision of which is indispensable for extracting the Weinberg angle. The experimental set up to laser cool and trap a single Ra$^+$ is underway. [Preview Abstract] |
Wednesday, June 15, 2011 3:12PM - 3:24PM |
K2.00007: Tests of the Equivalence Principle with Atom Interferometers Michael Hohensee, Holger M\"uller To a first approximation, gravity influences the motion of particles by changing the local flow of time. This ``gravitational redshift'' has been tested to an accuracy of $7\times10^{-5}$ by clock comparisons, and to $7\times 10^{-9}$ by matter wave interferometers. The wavefunction of a particle moving through spacetime is equivalent to a clock ticking at the Compton frequency $mc^{2}/h$ which traces out the same path. We will demonstrate this equivalence, proving that atoms are clocks. Moreover, we will show that they place stringent bounds on spin-independent, renormalizable violations of General Relativity. Matter wave interferometers may be among the few experiments sufficiently sensitive to detect higher order effects that arise through the nonlinearities of General Relativity. These effects are known to exist from solar system observations, but have never been confirmed in experiments under controlled laboratory conditions. [Preview Abstract] |
Wednesday, June 15, 2011 3:24PM - 3:36PM |
K2.00008: A Test for Tensor Lorentz Violating Fields Using a Rotating Comagnetometer Marc Smiciklas, Justin Brown, Michael Romalis The effective low-energy model of Lorentz violation described by the Standard Model Extension (SME) includes a number of tensor spin interactions that violate Lorentz symmetry but not CPT. Such interactions could be induced in popular Lorentz-violating theories, such as Horava theory of gravity and doubly-special relativity. We are performing a search for Lorentz-violating tensor spin interactions using a K-Rb-$^{21}$Ne comagnetometer. Compared to our previous work with a K-$^3$He comagnetometer, we expect to achieve significant improvements in energy sensitivity due to the smaller magnetic moment of $^{21}$Ne and use of hybrid optical pumping. Preliminary results searching for semisidereal modulations of the comagnetometer signal indicate that limits on tensor Lorentz violation can be improved by more than an order of magnitude. [Preview Abstract] |
Wednesday, June 15, 2011 3:36PM - 3:48PM |
K2.00009: Progress toward a search for anomalous spin-mass couplings with a dual-isotope rubidium magnetometer Julian Valdez, Ian Lacey, Rodrigo Peregrinaramirez, Derek Jackson Kimball We report progress in our development of a dual-isotope rubidium magnetometer to be used to search for a long-range coupling between proton spins and the mass of the Earth. The valence electron dominates magnetic interactions and serves as a precise co-magnetometer for the nuclei in a simultaneous measurement of Rb-85 and Rb-87 spin precession frequencies, enabling accurate subtraction of magnetic perturbations. Both Rb nuclei have valence protons, but in Rb-87 the proton spin is parallel to the nuclear spin and magnetic moment while for Rb- 85 the proton spin is anti-parallel to the nuclear spin and magnetic moment. Thus anomalous interactions of the proton spin produce a differential shift between the Rb spin- precession frequencies, whereas many sources of systematic error produce common-mode shifts of the spin-precession frequencies which can be controlled through auxiliary measurements. We discuss significant enhancement of the sensitivity through the use of new alkene-based antirelaxation coatings, and methods to control systematic effects due to light shifts, collisions, and the gyro-compass effect. [Preview Abstract] |
Wednesday, June 15, 2011 3:48PM - 4:00PM |
K2.00010: Prospects for Two-Photon Optical Magnetometry E.A. Alden, S.M. Degenkolb, T.E. Chupp, A.E. Leanhardt The $^1S_0 \rightarrow$ $^3D_2$ two-photon transition has been driven in an atomic ytterbium vapor using a pair of degenerate photons at 808 nm. Population in the excited state was detected via the $^3D_2 \rightarrow$ $^3P_1$ $\rightarrow$ $^1S_0$ cascade decay, which emits photons at 1479 nm and 556 nm, respectively. For Yb isotopes with nuclear spin, e.g. $^{171}$Yb with I=$\frac{1}{2}$, the transition rate is sensitive to the nuclear spin orientation and the laser polarization, which allows for possibility of performing two-photon optical magnetometry using the nuclear spin of a closed shell atom in its electronic ground state. While there are sufficiently accessible one-photon transitions in Yb to perform single-photon optical magnetometry, our technique generalizes to the noble gases, e.g. $^{129}$Xe with I=$\frac{1}{2}$, where reading out the ground state nuclear spin orientation is significantly more challenging. Relevance to ongoing permanent electric dipole moment experiments will be discussed. [Preview Abstract] |
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