Bulletin of the American Physical Society
49th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics APS Meeting
Volume 63, Number 5
Monday–Friday, May 28–June 1 2018; Ft. Lauderdale, Florida
Session H06: Tests of Basic Laws |
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Chair: Tanya Zelevinsky, Columbia University Room: Grand G |
Wednesday, May 30, 2018 8:00AM - 8:12AM |
H06.00001: Towards an improved electron and positron magnetic moment measurement as a test of the standard model and CPT symmetry Samuel Fayer, Thomas Myers, Xing Fan, Gerald Gabrielse An improved apparatus and a new measurement strategy will allow for significant increase in the precision of the electron magnetic moment measurement to below 0.28 ppt. The electron magnetic moment is the most precise test of the standard model \footnote{D. Hanneke, S. Fogwell, and G. Gabrielse, PRL 100 (2008) 120801} and, when combined with calculations, results in the most precise determination of the fine structure constant. Recent progress in theoretical calculations \footnote{S. Laporta, PLB, 772 (2017) 232}, which reduced the uncertainty in the QED corrections gives a basis for an improved measurement to test the standard model. The g-factor of positrons and electrons will be measured using quantum jump spectroscopy between the lowest energy states within a 100 mK cylinderical Penning trap. A direct comparison of the electron and positron magnetic moment gives the most precise test of CPT symmetry for the light leptons. This apparatus will allow for a measurement for the positron that is equally as precise as the electron, improving it by a factor of more than 15. Details of the developed measurement apparatus and recent progress towards the improved measurements for both the positron and electron will be presented. [Preview Abstract] |
Wednesday, May 30, 2018 8:12AM - 8:24AM |
H06.00002: Photodissociation of ThF$+$ and the eEDM Kia Boon Ng, Yan Zhou, Daniel Gresh, William Cairncross, Tanya Roussy, Kevin Boyce, Yuval Shagam, Lan Cheng, Jun Ye, Eric Cornell ThF$+$ has been chosen as the candidate for a third-generation measurement of the electric dipole moment of the electron (eEDM). Compared to the current HfF$+$ eEDM experiment, ThF$+$ has several advantages: (i) the eEDM-sensitive state (3$\Delta $1) is the ground state [1], which facilitates a long coherence time; (ii) and its effective electric field (35 GV/cm) is 50{\%} larger than that of HfF$+$ [2], which promises a direct increase of the eEDM sensitivity. However, molecular state detection is complicated by the molecular internal structure. Furthermore, current efficiency levels in the state preparation of ThF$+$ limits us to only a few hundred ThF$+$ ions within the trap for the eEDM experiment. Hence, we require a high-efficiency state readout method. One such method involves state-selective photodissociation of the ions, and counting the dissociated ions on a time-of-flight detector. However, the dissociating states of ThF$+$, which are required for the eEDM state readout, have not been found previously. Herein, we present the results of our spectroscopy of the ThF$+$ dissociating states, and our current progress in the state preparation of ThF$+$ for the eEDM experiment. [1] Gresh, Daniel N., et al. JMS 319 (2016): 1-9. [2] Skripnikov, L. V., and A. V. Titov. PRA 91.4 (2015): 042504. [Preview Abstract] |
Wednesday, May 30, 2018 8:24AM - 8:36AM |
H06.00003: Testing CPT with the Anti-hydrogen Molecular Ion Edmund Myers, David Fink, Jordan Smith High precision radio-frequency, microwave and infra-red spectroscopic measurements of the anti-hydrogen molecular ion $\bar{H}_{2}^{-}$ ($\bar{p}\bar{p}e^{+}$), compared with its normal matter counterpart, can provide direct tests of the CPT theorem. The fractional precision that can be achieved with such measurements can exceed that from comparing anti-protons with protons or anti-hydrogen with hydrogen. Schemes are outlined for measurements on a single $\bar{H}_{2}^{-}$ ion in a Penning trap, that use non-destructive state identification by measuring the cyclotron frequency and positron spin-flip frequency, and also methods for creating an $\bar{H}_{2}^{-}$ ion and initializing its quantum state. [Preview Abstract] |
Wednesday, May 30, 2018 8:36AM - 8:48AM |
H06.00004: Precision isotope shift measurement in decoherence-free subspace. Nitzan Akerman, Tom Manovitz, Ravid Shaniv, Yotam Shapira, Roee Ozeri Precision spectroscopies of atomic systems are playing an important role in the testing of fundamental physics. Recently, it was suggested to use linear King plots as bounds on new physics [arXiv:1704.05068]. This proposal calls for precision isotope shift spectroscopy of narrow optical transitions. To date, the best King plot were measured with precision on the order of 1 kHz and only very few isotope shift were measured at the Hz level. Here, we present a simple scheme to measure the isotope shift with milli-Hz precision level. Instead of measuring the absolute transition frequency for each of the isotopes separately, we extract only the shift by measuring the parity oscillations of two isotopes that were prepared in a decoherence-free subspace i.e. S$_{\mathrm{A}}$D$_{\mathrm{B}} \quad +$ D$_{\mathrm{A}}$S$_{\mathrm{B}}$. Interestingly, uncorrelated state can be use as well with a penalty of reducing the parity contrast by a factor of two. We demonstrate this method on the quadrupole transition S$_{\mathrm{1/2}}$ - D$_{\mathrm{5/2}}$ in Sr$^{\mathrm{+}}$ isotopes. Our measurement improves by six orders of magnitude over the previous measurement of this transition and forms one of most precise isotope shift measurement of optical transition. Our method can be easily implemented in existing setups of Ca$^{\mathrm{+}}$ and Yb$^{\mathrm{+}}$ ions which have enough stable isotope (without nuclear spin) to test King linearity to the sub-Hz level. [Preview Abstract] |
Wednesday, May 30, 2018 8:48AM - 9:00AM |
H06.00005: Constraints on Ultralight Dark Matter with an Optical Lattice Clock Colin Kennedy, Eric Oelker, Tobias Bothwell, Dhruv Kedar, Lindsay Sonderhouse, Edward Marti, Sarah Bromley, John Robinson, Jun Ye I report on experimental results of a search for ultralight dark matter by frequency comparison of a 21 cm, cryogenic, ultrastable silicon cavity to a 1D optical lattice clock. Sensitivity to dark matter is provided by the different couplings of the silicon atom bond length and the strontium atom clock transition to time variations in the fine structure constant, $\alpha$. Comparison of the length of a single crystal of silicon to the clock laser transition energy in strontium therefore provides a sensitive probe of time variation of $\alpha$. Experimental results will be presented in addition to a discussion of theories of ultralight dark matter which can be tested with this platform. [Preview Abstract] |
Wednesday, May 30, 2018 9:00AM - 9:12AM |
H06.00006: Progress towards a force sensor using Bloch oscillations to constrain dark matter theories Chandler Schlupf, Robert Niederriter, Kayla Rodriguez, Paul Hamilton We are developing an apparatus to search for physics beyond the Standard Model, such as ultra light dilaton dark matter [1]. This apparatus will use laser-cooled ytterbium to measure forces by observing Bloch oscillations of the atoms in an optical lattice [2]. This technique permits continuous measurements in a small volume with long coherence times providing sensitivity to time-varying forces, such as those expected from axion-like dark matter candidates. We present progress towards this goal, including the development of an optical cavity to maximize the consrast of Bloch oscillations. [1] A. Arvanitaki, J. Huang, and K. Van Tilburg, “Searching for dilaton dark matter with atomic clocks", Physical Review D 91, 015015 (2015). [2] B. Prasanna Venkatesh, M. Trupke, E. A. Hinds, and D. H. J. O'Dell, “Atomic Bloch-Zener oscillations for sensitive force measurements in a cavity", Physical Review A 80, 063834 (2009). [Preview Abstract] |
Wednesday, May 30, 2018 9:12AM - 9:24AM |
H06.00007: Tests of Lorentz and CPT Symmetry with Precision Experiments Yunhua Ding, V. Alan Kosteleck\'y Lorentz and CPT symmetry is fundamental in physics. However, tiny violation of this symmetry is possible in an underlying unified theory such as strings. This talk explores the theoretical and experimental prospects for Lorentz violation, focusing on electromagnetic interactions. The theory of Lorentz violation in quantum electrodynamics is presented, and experimental observables are established for precision experiments involving confined particles and antiparticles. New constraints on coefficients for Lorentz and CPT violation from existing data will be presented and prospective sensitivities in future experiments will be outlined. [Preview Abstract] |
Wednesday, May 30, 2018 9:24AM - 9:36AM |
H06.00008: Progress on a new pulsed $^{87}$Rb-$^{21}$Ne co-magnetometer Junyi Lee, Hudson Loughlin, Morgan Hedges, Michael Romalis Atomic co-magnetometers are sensitive gyroscopes and have also been used in many precision measurements to look for new physics beyond the Standard Model. In particular an alkali metal-noble gas co-magnetometer has been successfully used to place stringent limits on Lorentz and CPT violating interactions, anomalous spin-mass and spin-spin interactions. However, the signal of such a co-magnetometer suffers from low frequency drifts of the CW optical pumping light used to polarize the atoms. We report here the development of a new pulsed $^{87}$Rb-$^{21}$Ne co-magnetometer that has the potential to overcome these limitations. In this scheme, $^{87}$Rb is spin polarized by a short circularly polarized laser pulse and is then probed by off-resonant linearly polarized light. Fitting the decay signal to a model allows us to extract the signal of interest. We present simulation and experimental results of the pulsed co-magnetometer, calibrate the signal using Earth's rotation, and describe the low-frequency behavior of the system. [Preview Abstract] |
Wednesday, May 30, 2018 9:36AM - 9:48AM |
H06.00009: He-Xe co-magnetometers: systematics and sensitivity to new physics William Terrano, Jonas Meinel, Natasha Sachdeva, Tim Chupp Precision measurements of co-located and hyper-polarized $^3$He-$^{129}$Xe gases are a promising technique for searches for a wide variety of new physics that couples to nuclear spin, most of which are in principle inaccessible at accelerators. Especially important are measurements of: Lorentz-violation; CP-violation in the form of a Xe EDM; relics of high-energy symmetry breaking; and ultra-light dark matter axion scenarios. The power of such measurements stems from very high signal-to-noise ratios and long interrogation times, enabling extreme precision in the determination of the precession frequencies of the spins of the species. Unfortunately, so far such He-Xe co-magnetometers have not realized their potential due to a systematic shift between the $^3$He and $^{129}$Xe frequencies that changes by a few $\mu$Hz during each measurement, and limits the ability of this technique to identify new physics. This systematic has also been a subject to notable controversies in the community. I will present careful studies where we traced the issue back to residual longitudinal magnetization of the He and Xe, which affects the precession frequency of the two spin-species differently. Reducing this effect will greatly increase the potential physics reach of He-Xe co-magnetometers. [Preview Abstract] |
Wednesday, May 30, 2018 9:48AM - 10:00AM |
H06.00010: Demonstration of a Sensitive Method to Measure Nuclear Spin-Dependent Parity Violation Emine Altuntas, Jeffrey Ammon, Sidney Cahn, David DeMille Nuclear spin-dependent parity violation (NSD-PV) effects arise from exchange of the Z$^{\mathrm{0}}$ boson between electrons and the nucleus, and from interaction of electrons with the nuclear anapole moment, a parity-odd magnetic moment. We are studying NSD-PV effects using diatomic molecules, where the signal is 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 sensitivity to NSD-PV surpassing that of any previous atomic PV measurement, using the test system $^{\mathrm{138}}$Ba$^{\mathrm{19}}$F. We describe the concept of our experiment, our data, sources of uncertainty, and prospects of using this technique to measure aspects of the electroweak interaction that have prove difficult to determine with other methods. [Preview Abstract] |
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