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 R06: Fundamental Constants |
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Chair: David Hanneke, Amherst College Room: Grand G |
Thursday, May 31, 2018 10:30AM - 10:42AM |
R06.00001: Search for Time Variation of Fundamental Constants in Nonpolar Molecular Ions Ryan Carollo, Alexander Frenett, Christian Pluchar, David Hanneke Trapped and sympathetically cooled O$_2^+$ ions provide several paths to performing precision measurements of the time variation of the proton-to-electron mass ratio. We describe one such scheme, two-photon vibrational overtone transitions. The nonpolar nature of O$_2^+$ as well as its $^2\Pi_g$ ground state suppress many systematic effects. We discuss plans and progress towards a short-term goal on $\dot{\mu}/\mu$ that would match current limits set in molecular systems. The O$_2^+$ vibrational overtones have long-term prospects below the most stringent limit to date in any system. [Preview Abstract] |
Thursday, May 31, 2018 10:42AM - 10:54AM |
R06.00002: Comparisons of single-ion Yb$^+$ and Cs fountain clocks for searches for new physics Nils Huntemann, Christian Sanner, Richard Lange, Burghard Lipphardt, Johannes M. Rahm, Stefan Weyers, Christian Tamm, Ekkehard Peik We employ two single-ion Yb$^+$ optical clocks that use the $^2$S$_{1/2} \to {}^2$F$_{7/2}$ electric octupole (E3) transition as the reference. Because of their $3\times 10^{-18}$ uncertainty and the strong sensitivity of the transition frequency on the fine structure constant $\alpha$, comparisons with other atomic clocks enable improvements in searches for temporal variations of $\alpha$. A particularly suitable transition for such a comparison is the $^2$S$_{1/2} \to {}^2$D$_{3/2}$ electric quadrupole transition of the same ion, that we regularly use to test frequency shifts of the E3 transition induced by residual fields on a magnified scale. Besides investigations for variations of $\alpha$, long-term comparisons between the Yb$^+$ and Cs fountain clocks, with their frequency being sensitive to the proton-to-electron mass ratio $\mu$, allow us to improve present limits on the temporal variation of $\mu$ and use the data for searches for ultralight scalar dark matter. [Preview Abstract] |
Thursday, May 31, 2018 10:54AM - 11:06AM |
R06.00003: Highly Sensitive Molecular Ion Probe for Variation of the Proton-to- Electron Mass Ratio Mark Kokish, Patrick Stollenwerk, Masatoshi Kajita, Brian Odom Rovibrational transitions in molecules provide an unambiguous connection to the proton-to-electron mass ratio ($\mu$). However, difficulties in molecular state preparation, detection and control over systematics have prevented setting new limits on $\mu$-variation at the level set by analogous measurements in atoms. We identify a new molecular ion, TeH$^+$, which has unique properties that mitigate these challenges. Its electronic structure leads to highly diagonal Franck-Condon factors, which can be exploited to implement fast optical state preparation. Combined with its deep ground state potential well in the optical domain, statistical averaging for a single TeH$^+$ ion leads to a fractional precision comparable to that of single ion atomic clocks. Its 0$^+$ ground state is also relatively insensitive to systematic Zeeman and Stark shifts. These features all together reveal a promising candidate for setting a new limit on $\mu$-variation. [Preview Abstract] |
Thursday, May 31, 2018 11:06AM - 11:18AM |
R06.00004: Precision spectroscopy of the 2S-nP transitions in atomic hydrogen Lothar Maisenbacher, Vitaly Andreev, Arthur Matveev, Axel Beyer, Alexey Grinin, Randolf Pohl, Ksenia Khabarova, Nikolai Kolachevsky, Theodor W. H\"ansch, Thomas Udem Precision measurements of atomic hydrogen (H) have long been used to extract fundamental constants and to test bound-state quantum electrodynamics. Both Rydberg constant $R_\infty$ and proton RMS charge radius $r_p$ are determined significantly by H spectroscopy, requiring the measurement of at least two transitions. With the very precisely known 1S-2S transition frequency (C.\,G.\,Parthey et al., PRL 107, 203001 (2011)) as a corner stone, the limitation of this extraction is the measurement precision of other H transitions. Moreover, $r_p$ extracted from the H spectroscopy disagrees by 4 standard deviations with the value extracted from muonic hydrogen ($\mu$p) spectroscopy (A.\,Antognini et al., Science 339, 417 (2013)). Using a cryogenic beam of H atoms optically excited to the 2S state, we measured the 2S-4P transition with a relative uncertainty of 4 parts in $10^{12}$ (A.\,Beyer et al., Science 358, 79 (2017)). Combining our result with the 1S-2S result yields $R_\infty = 10973731.568076(96)$\,m$^{-1}$ and $r_p = 0.8335(95)$\,fm. Our $r_p$ value is 3.3 combined standard deviations smaller than the previous H world data, but in good agreement with the $\mu$p value. To further improve on this result, we are working on a measurement of the 2S-6P transition in H and deuterium. [Preview Abstract] |
Thursday, May 31, 2018 11:18AM - 11:30AM |
R06.00005: High precision measurement using atom interferometers with a Bose Einstein Condensate source. Leo Morel, Jun Sun, Pierre Clade, Sada Guellati-Khelifa The sensitivity of atom interferometers scales as the spatial separation between the two wavepackets. The ability to increase the area enclosed between the two arms of the atom interferometer being limited by the temperature of the atom source, a Bose Einstein Condensate (BEC) gaz would be a relevant source. However, an atom in a condensed state will experience a phase shift due to atom-atom interactions. We aim to use BEC to perform absolute precision measurements of the atom recoil velocity to determine the fine structure constant to a fraction of ppb. In this scope, we need a precise calibration of the systematic effect induced by interactions. We present the work we have done towards calibration of the mean field effect, as well as the most recent developments we made for the control, splitting, manipulation and recombination of a BEC. In particular, we will focus on the implementation of Large Momentum Transfer Beam Splitters, combining Raman transitions and Bloch Oscillations, and discuss the sensitivity enhancement they allow. [Preview Abstract] |
Thursday, May 31, 2018 11:30AM - 11:42AM |
R06.00006: Large Momentum Separation Contrast Interferometry with Yb Bose-Einstein condensates Katherine McAlpine, Daniel Gochnauer, Benjamin Plotkin-Swing, Subhadeep Gupta Using standing-wave light pulses on a Yb Bose-Einstein condensate (BEC) source, we demonstrate a symmetric three-path contrast atom interferometer with large momentum separation of up to 112 photon recoils between outer paths [1]. The interferometer phase evolution is quadratic with number of recoils, reaching a rate as large as 7\times $10^7$ radians/s. In addition to the symmetric geometry and narrow-momentum BEC source, the observed phase stability and robust scalability depends crucially on the suppression of undesired diffraction phases through a careful choice of atom optics parameters. We will discuss our theoretical model for these phases and compare to experimental results for various pulse parameters. We will also discuss the applicability of our method towards a new measurement of the fine-structure constant and a test of quantum electrodynamics. \\ \text{[1]} B. Plotkin-Swing et al, arXiv:1712.06738 [Preview Abstract] |
Thursday, May 31, 2018 11:42AM - 11:54AM |
R06.00007: Recoil-free even- and odd-parity transitions in an amplitude-modulated lattice potential Georg Raithel, Vladimir Malinovsky, Kaitlin Moore, Andira Ramos Transitions of Rydberg atoms trapped in a ponderomotive lattice can be driven by lattice amplitude modulation, which causes a ponderomotive (A-square) interaction. This spectroscopic method is ideal for high-resolution spectroscopy of Rydberg atoms, with applications in measuring the Rydberg constant and other atomic constants. We model the spectroscopic line shapes semiclassically, with classical center-of-mass motion (CM), and by using two descriptions with quantized CM (based on solving the time-dependent Schr\"odinger equation and on transition rates between spinor Bloch states). We find that the transitions allow Doppler-free, fourier-limited spectroscopy, with sub-kHz linewidth, at temperatures and lattice depths that require only moderate laser cooling. The change in vibrational quantum number can be even or odd, for even- and odd-parity electronic transitions, respectively. Certain even-parity cases minimize the trap-induced shift of the transition frequency. Results of the models, applications in high-precision spectroscopy, and related ongoing experimental work are discussed. [1] S. Anderson, K. Younge, G. Raithel, PRL {\bf 107}, 263001 (2011). [2] K. Moore, G. Raithel, PRL {\bf 115}, 163003 (2015). [3] A. Ramos, K. Moore, G. Raithel, PRA {\bf 96}, 032513 (2017). [Preview Abstract] |
Thursday, May 31, 2018 11:54AM - 12:06PM |
R06.00008: Measurement the Fine Structure Constant with Bragg Diffraction and Bloch Oscillations Weicheng Zhong, Richard Parker, Chenghui Yu, Brian Estey, Holger Müller Measurements of the fine structure constant $\alpha$, using methods from atomic, condensed-matter, and particle physics, are powerful tests of the overall consistency of theory and experiment across physics. We have measured $\alpha$ = 1/137.035999046(27), at $2.0×10^{-10}$ accuracy, via the recoil frequency of cesium-133 atoms in a matter-wave interferometer. We used multiphoton interactions such as Bragg diffraction and Bloch oscillations to increase the phase difference for the interferometer to over 12 million radians, which reduced the statistical uncertainty and enabled control of systematic effects at the 0.12 part-per-billion level. This is an unprecedented test of the standard model of particle physics, being the first direct measurement of $\alpha$ with an error below the 5th order quantum electrodynamics contribution in the electron's gyromagnetic anomaly. It also has implications for the unexplained anomaly of the muon’s magnetic moment, and strongly constrains multiple dark sector candidates as well as substructure of the electron. [Preview Abstract] |
Thursday, May 31, 2018 12:06PM - 12:18PM |
R06.00009: A miniature fountain in a portable atom interferometer for gravity measurement Fei Zi, Min Huang, Xian Zhang, Kaikai Huang, Xuanhui Lu By measuring the phase differences accumulated between atomic matter waves along different paths, atom interferometer is capable of many applications in fundamental physics, including measurement of gravity, Newton Constant, fine structure constant, even dark energy, gravitational wave and so on. However, making atom interferometer transportable for field work with guaranteed accuracy is still one of the main focus in this area. Here, we demonstrate a compact atom interferometer for measuring gravity by using a fountain and fiber-based optical-setup. We use two ECDLs for all trap and detection lights and produce the Raman pairs via the injection locking method utilizing a homemade ECDL with high phase coherence. In order to make the setup compact, we also modularized a part of the system, such as DAVLL locking module and beam splitting module. In the experiment, we capture 10$^{\mathrm{6}}$ atoms at 8.5 $\mu $K from the background vapor and achieve fringes with good visibility in the Mach-Zehnder geometry. We measured the gravity with the sensitivity $\Delta $g/g of 4.5$\times $10$^{\mathrm{-7}}$. Being simple and robust, our miniature atom interferometer aims at improved sensitivity and to be functioned outside of lab for local gravity. [Preview Abstract] |
Thursday, May 31, 2018 12:18PM - 12:30PM |
R06.00010: Long-Range Tails in van der Waals Interactions Ulrich Jentschura, Chandra Adhikari, Vincent Debierre We investigate the oscillatory long-range tails of long-range interatomic interactions, based on a quantum electrodynamic formalism. The matching of the scattering amplitude to the effective Hamiltonian conclusively answers any questions regarding the placement of the so-called pole terms, which correspond to a very particular physical process, namely, virtual resonant emission into an energetically lower atomic state. The resonant process leads to conceptually interesting, but numerically small, oscillatory long-range tails. These tails drastically differ from the predictions of Casimir-Polder theory [Phys. Rev. Lett. 118, 123001 (2017)]. Phenomenologically, it is interesting to note that for the first time, we are now in the position to also calculate the short-range, non-retarded, van der Waals effects for systems involving excited (Rydberg) atoms. The van der Waals coefficients, in atomic units, are found to be in the range of a few 100,000. The calculations enable us to estimate the pressure shift of such transitions, which are crucial for the determination of fundamental constants from current, and planned, high-precision measurements involving simple atomic systems. [Preview Abstract] |
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