Bulletin of the American Physical Society
2006 37th Meeting of the Division of Atomic, Molecular and Optical Physics
Tuesday–Saturday, May 16–20, 2006; Knoxville, TN
Session K4: Fundamental Symmetries and Precision Measurements |
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Chair: Siu Au Lee, Colorado State University Room: Knoxville Convention Center 301E |
Thursday, May 18, 2006 8:00AM - 8:12AM |
K4.00001: Cold Molecular Ion Source for an electron EDM measurement Russell Stutz, Aaron Leanhardt, Laura Sinclair, Eric Cornell Molecular ions confined inside a Paul trap offer a potentially sensitive system for a search of the electron electric dipole moment. Large effective electric fields at the electron can be obtained by using molecules. Trapping these molecules allows for long spin coherence times to probe electron EDM induced energy splittings. We report on a supersonic expansion that cools ions created from laser ablation to temperatures of $\sim 1$~K. At these temperatures our proposed molecular ions (HfH+ or PtH+) would be cooled to their rovibrational ground states. Future work includes creation of HfH+ and loading these ions into a linear Paul trap while maintaining low temperatures. [Preview Abstract] |
Thursday, May 18, 2006 8:12AM - 8:24AM |
K4.00002: Laser trapping of Radium and progress towards an electric dipole moment measurement J.R. Guest, N. D. Scielzo, I. Ahmad, K. Bailey, J. P. Greene, R. J. Holt, Z.-T. Lu, T. P. O'Connor, D. H. Potterveld, H. Gould Permanent electric dipole moments (EDMs) in atoms or molecules are signatures of Time (T)-and Parity (P)-violation and represent an important window onto physics beyond the Standard Model. We are developing a next generation EDM search around laser-cooled and trapped Ra-225. Due to octupole deformation of the nucleus, Ra-225 is predicted to be two to three orders of magnitude more sensitive to T-violating interactions than Hg-199, which currently sets the most stringent limits in the nuclear sector. We will discuss our progress, including the successful laser cooling and trapping of Ra-226 atoms. Using the $^{1}$S$_{0}$ F=0 -- $^{3}$P$_{1}$ F=1 transition, we have demonstrated transverse cooling, Zeeman slowing, and capture of Ra-226 atoms in a magneto-optical trap (MOT). By repumping the $^{3}$D$_{1}$ dark state to the $^{1}$P$_{1}$ state, which decays back to ground $^{1}$S$_{0}$ state, we have extended the lifetime of the trap from milliseconds to seconds. [Preview Abstract] |
Thursday, May 18, 2006 8:24AM - 8:36AM |
K4.00003: Progress Towards a Measurement of the Electric Dipole Moment of the Electron Sarah Bickman, Paul Hamilton, Yong Jiang, David Kawall, Richard Paolino, David DeMille We have proposed a measurement of the electric dipole moment of the electron ($d_e$) using the metastable a(1) ($^3\Sigma^+$) state of the PbO molecule. A non-zero measurement of $d_e$ within the next few orders of magnitude beyond the current limit of (6.9 $\pm$ 7.4) $\times$ $10^{-28}$ e-cm[1] would be clear evidence for physics beyond the standard model. We will present recent results from and improvements to our experiment including a proof of principle for the experiment, recent data on the initial state preparation using stimulated microwave Raman transitions, and a new detection system. The new detection system uses Winston Cone optical concentrators and large-area, low-noise, high speed, photodiode-based fluorescence detectors with fast overdrive recovery [2].\newline \newline [1] B. C. Regan, Eugene D. Commins, Christian J. Schmidt, and David DeMille, Phys. Rev. Lett. \textbf{88}, 071805 (2002) \newline [2] S. Bickman and D. DeMille, Rev. Sci. Instr. \textbf {76},113101 (2005). [Preview Abstract] |
Thursday, May 18, 2006 8:36AM - 8:48AM |
K4.00004: Ba$^{+}$ vs. Cs: prospects for parity-nonconservation studies M.S. Safronova, E. Iskrenova-Tchoukova We conduct a systematic study of Ba$^+$ atomic properties using a relativistic all-order method. Energy levels, transition matrix elements, lifetimes, hyperfine constants, and polarizabilities are calculated. This work is motivated by the possibility to study the parity nonconservation (PNC) with a single trapped ion. Comparison of the experimental weak charge of an atom $Q_W$ (a quantity which depends on input from atomic theory) with predictions provides important constraints on possible extensions of the standard model. The experimental value of $Q_W$ is known to 0.5\% for Cs and 3\% for Tl, the uncertainty in both cases being dominated by atomic theory. Since the Cs PNC studies provided the most accurate determination of $Q_W$ of such kind, we conduct a detailed comparison of accuracy of our Ba$^+$ calculations with the corresponding calculations in Cs. We also calculate the ratio of the light shift in the $6s$ and $5d_{5/2}$ states in Ba$^+$ at various wavelengths and consider the prospects of the precise determination of the Ba$^+$ electric-dipole matrix elements from the combination of the theoretical and experimental [1] studies of the light shift ratios. \\ \noindent [1] J. A. Sherman, T. W. Koerber, A. Markhotok, W. Nagourney, and E. N. Fortson, Phys. Rev. Lett. 94, 243001 (2005) [Preview Abstract] |
Thursday, May 18, 2006 8:48AM - 9:00AM |
K4.00005: Gravitational Tests of Lorentz Symmetry with Atoms Jay D. Tasson, V. Alan Kostelecky Violations of Lorentz symmetry provide a potential signal for new physics at the Planck scale. ~At our present energy scales, general Lorentz violation is described by the Standard-Model Extension (SME). ~In this talk, I will give an outline of the fermion sector of the SME and describe a new sensitivity to Lorentz violation that is attainable in experiment, arising from gravitational interactions with atoms. [Preview Abstract] |
Thursday, May 18, 2006 9:00AM - 9:12AM |
K4.00006: Progress ttrapping single indium ions for possible frequency reference William Trimble, Jeff Sherman, Warren Nagourney The $^1$S$_0 \rightarrow ^3$P$_0$ transition in the In$^+$ ion at 237 nm has a natural linewidth of 0.8 Hz and is a promising candidate for an optical frequency reference. Since this ``clock'' transition is J=0 $\rightarrow$ J=0, it lacks shifts from the electric quadrupole interaction, a leading systematic in some ions under investigation. This transisition coincides with the fourth harmonic of the 946 nm line available from already narrow-linewidth Nd:YAG lasers. We report recent developments in spectroscopy of single In$^+$ ions using a Paul-Staubel trap and a new frquency-quadrupled diode laser to excite the stronger $^1$S$_0 \rightarrow ^3$P$_1$ transition at 230 nm. We also propose comparisons between the indium ion frequency reference and other frequency references at the University of Washington. [Preview Abstract] |
Thursday, May 18, 2006 9:12AM - 9:24AM |
K4.00007: An Aluminum Ion Optical Clock Using Quantum Logic T. Rosenband, P.O. Schmidt, D.B. Hume, T.M. Fortier, W.H. Oskay, J.C.J. Koelemeij, K. Kim, W.M. Itano, S.A. Diddams, J.C. Bergquist, R.E. Drullinger, D.J. Wineland The 267 nm $^1$S$_0 \rightarrow ^3$P$_0$ transition in $^{27}$Al$^+$ combines several attractive characteristics as an atomic reference for an optical clock with high stability and accuracy. Its sharp clock transition (7 mHz natural linewidth) has a very small electric quadrupole moment, a low quadratic Zeeman coefficient (0.7 Hz/gauss$^2$), as well as a small room temperature blackbody shift ($\Delta\nu/\nu < 10^{-17})$. We have used quantum logic based spectroscopy$^{a,b}$ to operate an Al$^+$ optical frequency standard in which a stable laser oscillator at 534 nm is doubled and locked to the Al$^+$ $^1$S$_0 \rightarrow ^3$P$_0$ transition. The frequency of this optical standard was compared to the NIST $^{199}$Hg$^+$ optical frequency standard using a femtosecond frequency comb, resulting in a frequency ratio measurement with $\Delta\nu/\nu < 10^{-16}$ statistical uncertainty. The systematic uncertainty in the Al$^+$ clock frequency has a similar magnitude, and is dominated by second order Doppler shifts due to secular motion and micromotion. \newline [a] D. J. Wineland \emph{et al.}, Proc. 6th Symp. on Freq. Standards and Metrology, 361 (2002) \newline [b] P. O. Schmidt \emph{et al.}, Science \textbf{309}, 749 (2005) [Preview Abstract] |
Thursday, May 18, 2006 9:24AM - 9:36AM |
K4.00008: N-resonance characterization for compact atomic clocks Cindy Hancox, Irina Novikova, Yanhong Xiao, David Phillips, Ronald Walsworth There is great current interest in developing small atomic clocks with low power consumption and fractional frequency stability of $10^{-12}/\sqrt{\tau/s}$ or better. N-resonances, all-optical three-photon-absorption resonances, offer a promising alternative to CPT-based clocks due to their high resonance contrast and the potential to cancel first-order light shifts. We present measurements of the N- resonance contrast, width and light-shift for $^{87}$Rb in a compact (1 mm long) vapor cell. [Preview Abstract] |
Thursday, May 18, 2006 9:36AM - 9:48AM |
K4.00009: Improved performance of the ${}^{129}$Xe/${}^3$He Zeeman maser Alex Glenday, Federico Cane, Matthew Rosen, David Phillips, Ronald Walsworth We report recent improved performance of the ${}^{129}$Xe/${}^3$He Zeeman maser, which enables a more sensitive measurement constraining Lorentz and CPT and violation. Improved temperature and mechanical stability of the maser as well as signal optimization have led to an order of magnitude improvement in frequency noise and stability. Experimental investigations of Lorentz and CPT symmetry provide important tests of the framework of the standard model of particle physics and theories of gravity. [Preview Abstract] |
Thursday, May 18, 2006 9:48AM - 10:00AM |
K4.00010: Differential phase shift spectroscopy in a thallium atomic beam Protik Majumder, David Butts, Ralph Uhl We have developed a new differential phase shift spectroscopy system capable of detecting atom-induced optical cavity shifts at the microradian level. An in-vacuum three-mirror ring cavity is oriented normal to the propagation of an atomic beam. The frequencies of two counter-propagating optical beams are offset by exactly one cavity free spectral range. By locking the transmission signal of one laser beam to the steep slope of a cavity transmission fringe, we detect relative transmission changes in the two beams. While taking advantage of a high degree of common mode noise rejection, we remain sensitive to small phase shifts induced by the atoms as they interact with one laser beam at a time. We plan to measure the Stark shift and Stark-induced amplitude in the E1-forbidden 6P$_{1/2}\rightarrow$ 6P$_{3/2}$ 1283 nm transition in thallium, providing important atomic structure information in an atomic system for which high-precision parity nonconservation results exist. Current results will be presented. Using common-frequency counterpropagating beams, the identical apparatus will also be used to search for a long-range Time-reversal-violating force in thallium which would again manifest itself as a differential optical cavity phase shift, now correlated with the direction of a static electric field. [Preview Abstract] |
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