Bulletin of the American Physical Society
47th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 61, Number 8
Monday–Friday, May 23–27, 2016; Providence, Rhode Island
Session H5: Electric-Dipole Searches and Tests of Fundamental Symmetries |
Hide Abstracts |
Chair: Elizabeth Petrik, Harvard University Room: 551AB |
Wednesday, May 25, 2016 10:30AM - 10:42AM |
H5.00001: Updated measurement of the permanent electric dipole moment (EDM) of $^{199}$Hg Brent Graner, Yi Chen, Eric Lindahl, Blayne Heckel A permanent electric dipole moment (EDM) in an atom or particle would prove that time reversal symmetry is broken. In addition, an atomic EDM may provide evidence of new physics or CP symmetry violation in the strong sector. We have recently completed an improved measurement of the EDM of $^{199}$Hg utilizing a set of vapor cells containing isotopically-enriched $^{199}$Hg optically pumped and probed with UV laser light. I will discuss the most recent iteration of the experiment, and present unblinded results. [Preview Abstract] |
Wednesday, May 25, 2016 10:42AM - 10:54AM |
H5.00002: Systematic errors in the measurement of the permanent electric dipole moment (EDM) of the $^{199}$Hg atom Yi Chen, Brent Graner, Blayne Heckel, Eric Lindahl This talk provides a discussion of the systematic errors that were encountered in the $^{199}$Hg experiment described earlier in this session. The dominant systematic error, unseen in previous $^{199}$Hg EDM experiments, arose from small motions of the Hg vapor cells due to forces exerted by the applied electric field. Methods used to understand this effect, as well as the anticipated sources of systematic errors such as leakage currents, parameter correlations, and E$^2$ and $\mathbf{v}\times\mathbf{E}/c$ effects, will be presented. The total systematic error was found to be 72\% as large as the statistical error of the EDM measurement. [Preview Abstract] |
Wednesday, May 25, 2016 10:54AM - 11:06AM |
H5.00003: An improved limit on the EDM of $^{\mathrm{225}}$Ra Michael Bishof, Kevin Bailey, Matthew R. Dietrich, John P. Greene, Roy J. Holt, Mukut R. Kalita, Wolfgang Korsch, Nathan D. Lemke, Zheng-Tian Lu, Peter Mueller, Thomas P. O'Connor, Richard H. Parker, Tenzin Rabga, Jaideep T. Singh Searches for permanent electric dipole moments (EDMs) are sensitive probes of symmetry violation that could explain the dominance of matter over anti-matter. The $^{\mathrm{225}}$Ra (t$_{\mathrm{1/2}}=$15 days, I$=$1/2) atom is a particularly attractive system to use for an EDM measurement because its octupole-deformed nucleus, closely spaced ground-state parity doublet, and large nuclear charge make $^{\mathrm{225}}$Ra uniquely sensitive to symmetry-violating interactions in the nuclear medium. In 2015, we reported the first ``proof of principle'' measurement of the $^{\mathrm{225}}$Ra EDM, giving a 95{\%} confidence upper limit of 5*10$^{\mathrm{-22}}$ e-cm; representing the first EDM measurement using laser-trapped atoms as well as the first EDM measurement of an atom with an octupole-deformed nucleus. After implementing upgrades to our apparatus, we now observe nuclear spin coherence after 20 s of free evolution -- a factor of ten improvement. A new EDM measurement based on the upgraded system improved the 95{\%} confidence upper limit by a factor of 36. We also report on the progress of current experimental upgrades that have the potential to further improve our EDM sensitivity by many orders of magnitude, allowing us to test symmetry violation at an unprecedented level. [Preview Abstract] |
Wednesday, May 25, 2016 11:06AM - 11:18AM |
H5.00004: Quantum State Magnification Nils Engelsen, Onur Hosten, Rajiv Krishnakumar, Mark Kasevich The standard quantum limit (SQL) for quantum metrology has been surpassed by as much as a factor of 100 using entangled states. However, in order to utilize these states, highly engineered, low-noise state readout is required. Here we present a new method to bypass this requirement in a wide variety of physical systems. We implement the protocol experimentally in a system using the clock states of $5\times10^5$ $^{87}$Rb atoms. Through a nonlinear, optical cavity-mediated interaction we generate spin squeezed states. A small microwave rotation followed by an additional optical cavity interaction stage allow us to exploit the full sensitivity of the squeezed states with a fluorescence detection system. Though the technical noise floor of our fluorescence detection is 15dB above the SQL, we show metrology at 8dB below the SQL. This is the first time squeezed states prepared in a cavity are read out by fluorescence imaging. The method described can be used in any system with a suitable nonlinear interaction. [Preview Abstract] |
Wednesday, May 25, 2016 11:18AM - 11:30AM |
H5.00005: Progress Toward a Ten-Times Better Measurement of the Electron's EDM with ThO Brendon O'Leary, Vitaly Andreev, Daniel Ang, Jacob Baron, David DeMille, John Doyle, Gerald Gabrielse, Nicholas Hutzler, Zack Lasner, Cristian Panda, Elizabeth Petrik, Christian Weber, Adam West, Grey Wilburn The ACME experiment recently improved the limit on the electron's electric dipole moment (EDM) by a factor of 10 by performing spin-precession measurements on a molecular beam of ThO (Science 343 (2014), 269-272). Since that measurement, we have implemented and demonstrated a series of improvements that will increase the statistical sensitivity to the EDM by another factor of 10, including methods to increase the efficiency of molecular state preparation and detection. Additional improvements are projected to suppress known systematic errors to a level below the new target statistical uncertainty. The largest systematic errors in our first measurement arose due to thermal stress-induced birefringence and an E1-M1 interference effect; we will describe our approach to dramatically reduce each of these effects. [Preview Abstract] |
Wednesday, May 25, 2016 11:30AM - 11:42AM |
H5.00006: Thermochemical Beam Source of ThO for Measuring the Electric Dipole Moment of the Electron Elizabeth Petrik, Jacob Baron, Nick Hutzler, Zack Lasner, Brendon O'Leary, Cristian Panda, Adam West, Grey Wilburn, David DeMille, Gerald Gabrielse, John Doyle The observation of an electron electric dipole moment (eEDM) would reveal new sources of time-reversal symmetry violation, potentially shedding light on the excess of matter over antimatter in the universe. Certain heavy polar molecules have a large interaction between the nuclear electric field and the eEDM that can be interrogated in the lab, making them ideal for eEDM searches. This molecular feature allowed our measurement with thorium monoxide (ThO) to set the most stringent upper limit on the eEDM to date [1]. Producing enough such molecules in the gas phase to perform a precision measurement is challenging because of their reactivity and low vapor pressure. Thus, a cryo buffer gas beam source yielding a high flux ($10^{13}$/s) of cold (4~K), slow (170~m/s) ThO via laser ablation of ThO$_2$ [2] was critical to our success. We now report on progress towards an improved beam source, which relies on favorable thorium-oxygen chemistry to produce gas-phase ThO via laser heating of a mixture of ThO$_2$ and Th. This new source has an average beam flux $>5$ times larger than in [2] and will contribute to a future eEDM measurement with greatly improved statistics. [1] ACME, Science 343, (2014) 269. [2] N.~Hutzler et al., PCCP 13, (2011) 18976. [Preview Abstract] |
Wednesday, May 25, 2016 11:42AM - 11:54AM |
H5.00007: Progress of the JILA electron EDM experiment Daniel Gresh, William Cairncross, Kevin Cossel, Matt Grau, Kia Boon Ng, Yan Zhou, Yiqi Ni, Jun Ye, Eric Cornell A nonzero permanent electric dipole moment of the electron (eEDM) would have important implications for extensions to the Standard Model of particle physics. The JILA eEDM experiment uses trapped HfF$^+$ ions to attain large effective electric fields and long measurement coherence times. In our ion trap we prepare HfF$^+$ in a low-lying, metastable $^3\Delta_1$ state and perform Ramsey spectroscopy between two Zeeman sub-levels in the presence of rotating electric and magnetic bias fields with free-evolution times of $>$ 500 ms. Using this technique, we have thoroughly investigated sources of systematic error and have recently suppressed several of our leading systematics to the $10^{-30}$ $e\cdot$cm level. Here, we present the results from our systematic error investigations and from a high-precision eEDM-sensitive 100-hour data run. [Preview Abstract] |
Wednesday, May 25, 2016 11:54AM - 12:06PM |
H5.00008: Increasing measurement sensitivity for the electron's electric dipole moment using trapped molecular ions Yan Zhou, Daniel Gresh, William Cairncross, Matt Grau, Kia Boon Ng, Yiqi Ni, Eric Cornell, Jun Ye Based on our latest measurements of the electron's electric dipole moment (eEDM) using trapped HfF$^+$ ions, after 100 hours of data collection, the statistical error still dominates in our overall uncertainty budget \footnote{Daniel N Gresh's presentation}. Overcoming the bottleneck of limited statistical sensitivity can increase the precision of the eEDM measurement directly. Here, we present the progress of three ongoing experiments: (1) applying STImulated Raman Adiabatic Passage (STIRAP) with rotating linear polarization for increased coherent population transfer from the ground $X^1\Sigma^+$ state to the eEDM-sensitive $^3\Delta_1$ state; (2) implementing a new ion-counting detector toward shot-noise limited sensitivity with significant suppression technical noise; (3) exploring the possibility of using the ground $^3\Delta_1$ state of ThF$^+$ ions to realize a larger effective electric field and a longer coherence time. These experiments provide a route towards an order of magnitude increase in statistical sensitivity in the second generation of measurements. [Preview Abstract] |
Wednesday, May 25, 2016 12:06PM - 12:18PM |
H5.00009: Nuclear Spin Dependent Parity Violation in Diatomic Molecules Emine Altuntas, Sidney Cahn, David DeMille, Mikhail Kozlov Nuclear spin-dependent parity violation (NSD-PV) effects arise from exchange of the $Z^{0}$ boson between electrons and the nucleus, and from interaction of electrons with the nuclear anapole moment, a parity-odd magnetic moment. The latter scales with nucleon number of the nucleus $A$ as $A^{2/3}, $whereas the $Z^{0}$ coupling is independent of $A$. Thus the former is the dominant source of NSD-PV for nuclei with $A\ge $\textit{20}. We study NSD-PV effects using diatomic molecules, where signals are dramatically amplified by bringing rotational levels of opposite parity close to degeneracy in a strong magnetic field. The NSD-PV interaction matrix element is measured using a Stark-interference technique. We present results that demonstrate statistical sensitivity to NSD-PV effects surpassing that of any previous atomic parity violation measurement, using the test system~$^{\mathrm{138}}$Ba$^{\mathrm{19}}$F. We report our progress on measuring and cancelling systematic effects due to combination of non-reversing stray $E$-fields, $E_{nr}$ with $B$-field inhomogeneities. Short-term prospects for measuring the nuclear anapole moment of $^{\mathrm{137}}$Ba$^{\mathrm{19}}$F are discussed. In the long term, our technique is sufficiently general and sensitive to enable measurements across a broad range of nuclei. [Preview Abstract] |
Wednesday, May 25, 2016 12:18PM - 12:30PM |
H5.00010: Probing the Higgs force with isotope shift spectroscopy Roee Ozeri, Cedric Delaunay, Gilad Perez, Yotam Soreq The Higgs boson, the last missing piece of the Standard Model (SM) of elementary particles, was recently observed by experiments in the Large Hadron Collider (LHC). To check whether this is indeed the SM Higgs, its coupling to other elementary particles should be experimentally measured. Current limits placed by LHC experiments on the coupling of the Higgs to the main building block of matter; the electron and the up and down quarks; are orders of magnitude larger than the SM predictions. Here, we propose to use the measurement of isotope shifts in optical atomic clock transitions to probe the Higgs boson coupling to electrons and nuclei. We show that the Higgs force between nuclei and bound electrons induces measurable nonlinearities to the King relation between isotope shifts [1]. With current state-of-the-art accuracy in frequency comparison, limits which compete with, or even surpass, the bounds provided by LHC experiments can be achieved. Improved knowledge of these couplings is an important test of the SM. Similarly, this measurement could lead to an improved sensitivity to the presence of new physics. [1] arXiv:1601.05087 [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700