Bulletin of the American Physical Society
53rd Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 67, Number 7
Monday–Friday, May 30–June 3 2022; Orlando, Florida
Session E11: Precision SpectroscopyRecordings Available
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Chair: Daniel Felinto Barbosa, Universidade Federal de Pernambuco Room: Grand Ballroom E |
Tuesday, May 31, 2022 2:30PM - 2:42PM |
E11.00001: Measurement of the 2S1/2-8D5/2 Transition in Atomic Hydrogen Adam Brandt, Samuel F Cooper, Cory Rasor, Zak Burkley, Dylan C Yost Spectroscopy of atomic hydrogen plays a vital role in precision tests of quantum electrodynamics, and in the determination of the Rydberg constant and proton charge radius. Here, we present a measurement of the 2S1/2-8D5/2 transition on a cryogenic beam of atomic hydrogen. The measured frequency is 770649561570.9(2.0) kHz, which represents a relative uncertainty of 2.6 x 10-12 -- a three-fold improvement over the previous best measurement. We will discuss our characterization of the systematic effects with a focus on the ac- and dc-Stark shifts. Combining our measurement with the most recent measurement of the 1S-2S transition in atomic hydrogen, we extract a proton radius that has a combined 3.1σ disagreement with the most recent CODATA 2018 recommended value. |
Tuesday, May 31, 2022 2:42PM - 2:54PM |
E11.00002: Precision spectroscopy of the 2S-6P transition in atomic hydrogen and deuterium Vitaly Wirthl, Lothar Maisenbacher, Derya Taray, Alexey Grinin, Arthur Matveev, Omer Amit, Randolf Pohl, Theodor Hansch, Thomas Udem Both atomic hydrogen and deuterium can be used to determine physical constants and to test Quantum Electrodynamics. Combining the 1S-2S with additional transition frequency measurements in each isotope separately, one can extract the deuteron radius independent of the proton radius and vice versa [1]. We recently measured the 2S-6P transition in hydrogen, and here report on the status of the ongoing analysis. We also performed a preliminary measurement of the 2S-6P transition in deuterium, where no recent result is available and a discrepancy with muonic deuterium persists [2]. Compared to hydrogen, precision spectroscopy of the same transition in deuterium is complicated by simultaneous excitation of hyperfine transitions, possibly leading to unresolved quantum interference [3]. Since these effects depend on laser polarization, we developed an active fiber-based retroreflector with a polarization monitor [4]. Furthermore, we find that in our case the unresolved quantum interference is suppressed, making a 2S-6P deuterium measurement with similar precision as for hydrogen feasible. |
Tuesday, May 31, 2022 2:54PM - 3:06PM |
E11.00003: Ramsey Spectroscopy of the 2S Hyperfine Interval in Cryogenically-Cooled Hydrogen Cory Rasor, Ryan Bullis, Samuel F Cooper, Dylan C Yost Hydrogen, due to its simple structure, has been paramount to the development of quantum mechanics and quantum electrodynamics (QED). One of the most accurate physical measurements in hydrogen is the 1S hyperfine interval, HF1S, with a fractional uncertainty of about 1 × 10-12. However, the theoretical prediction for this interval is limited by complications arising from proton structure. The difference D21 = HF1S - 8HF2S, where HF2S is the hyperfine interval of the 2S state, nearly avoids proton structure uncertainty and is theoretically determined to fourth-order in bound-state QED. Currently, the experimental uncertainty for D21 is about 20 times larger than the theory and is limited by the experimental determination of the 2S hyperfine interval. In this talk, we will discuss an ongoing measurement of the hydrogen 2S hyperfine interval using Ramsey spectroscopy on a cold (5 K) beam of atomic hydrogen. |
Tuesday, May 31, 2022 3:06PM - 3:18PM |
E11.00004: Search for the 4f146s2 1S0-4f135d6s2(J=2) transition in Yb towards a search for the time variation of fine structure constant Akio Kawasaki, Takumi Kobayashi, Akiko Nishiyama, Takehiko Tanabe, Masami Yasuda The 4f146s2 1S0-4f135d6s2(J=2) transition in ytterbium (Yb) at 431 nm is theoretically predicted as a narrow-linewidth transition that has high sensitivity for the variation of the fine structure constant, and it also has some other interesting features such as a transition with f-orbital electron excited in neutral Yb and large electronic structure difference from known clock transitions. We are searching for this 4f146s2 1S0-4f135d6s2(J=2) transition with Yb atoms laser-cooled by a magneto-optical trap formed by the 4f146s2 1S0-4f146s6p 3P1 transition. The current status of the search with our optical lattice clock system is presented. Establishing the spectroscopy of this transition leads to the more precise test of the time variation of the fine structure constant and the dark matter search with nonlinearity of the King plot. |
Tuesday, May 31, 2022 3:18PM - 3:30PM |
E11.00005: Reexamination of transition polarizabilities in experiments on atomic parity violation Di Xiao Stark interference is a ubiquitous technique in experiments on atomic parity-violation (APV). In $^{133}{\rm Cs}$, the central quantity of interest, the $6S\rightarrow{7S}$ APV transition amplitude, $E_{\mathrm{APV}}$, is deduced from the measured ratio of $E_{\mathrm{APV}}$ to the vector transition polarizability $\beta$, $E_{\mathrm{APV}}/\beta$. Ideally, the uncertainty in $\beta$ should be much smaller than that of the above ratio. The $E_{\mathrm{APV}}/\beta$ ratio was measured with a $0.35\%$ uncertainty by the Boulder group [Science 275, 1759 (1997)]. However, currently, there is an alarming discrepancy in different determinations of $\beta$. The most recent determination [PRL 123, 073002 (2019)] of $\beta$ claimed an error bar of $\sim 0.2\%$ comparable to that of the earlier measurement [PRL 82, 2484 (1999)]. However, the central values of the two determinations of $\beta$ differ by $\sim 0.7\%$, severely limiting APV interpretation. Here, we re-examine computations of $\beta$ and investigate the role of higher-order, hyperfine interaction induced, corrections to transition polarizabilities. |
Tuesday, May 31, 2022 3:30PM - 3:42PM |
E11.00006: New theoretical approach to high precision evaluation of atomic-parity violating amplitudes Hoang Bao Tran Tan, Andrei P Derevianko, Di Xiao We formulate a parity-mixed coupled-cluster (PM-CC) approach for high-precision calculations of parity non-conserving amplitudes in mono-valent atoms. Compared to the conventional formalism which uses parity-proper (PP) one-electron orbitals, the PM-CC method is built using parity-mixed (PM) orbitals. The PM orbitals are obtained by solving the Dirac-Hartree-Fock equation with the electron-nucleus electroweak interaction included (PM-DHF). There are several advantages to such a PM-CC formulation: (i) reduced role of correlations, as for the most experimentally-accurate to date Cs 6S1/2-7S1/2 transition, the PM-DHF result is only 3% away from the accurate many-body value, while the conventional DHF result is off by 18%; (ii) avoidance of directly summing over intermediate states in expressions for parity non-conserving amplitudes which reduces theoretical uncertainties associated with highly-excited and core-excited intermediate states, and (iii) relatively straightforward upgrade of existing and well-tested large-scale PP-CC codes. We reformulate the CC method in terms of the PM-DHF basis and demonstrate that the cluster amplitudes are complex numbers with opposite parity real and imaginary parts. We then use this fact to map out a strategy through which the new PM-CC scheme may be implemented. |
Tuesday, May 31, 2022 3:42PM - 3:54PM |
E11.00007: Towards quantum control and spectroscopy of a single hydrogen molecular ion Nick Schwegler, David Holzapfel, Jonathan P Home, Daniel Kienzler The complexity and variety of molecules offer opportunities for metrology and quantum information that go beyond what is possible with atomic systems. The hydrogen molecular ion is the simplest of all molecules and can thus be calculated ab initio to very high precision. Combined with spectroscopy this allows to determine fundamental constants and test fundamental theory at record precision. Spectroscopy should improve substantially by performing experiments with single H2+ ions, reducing systematic uncertainties and improving signal strength. This necessitates quantum control. |
Tuesday, May 31, 2022 3:54PM - 4:06PM |
E11.00008: Broadband (3.1-5.4 µm) mid-IR dual-comb molecular spectroscopy with sub-MHz resolution. Andrey Muraviev, Dmittri Konnov, Konstantin L Vodopyanov We demonstrated a broadband mid-IR spectroscopy with sub-MHz resolution using a dual-comb spectroscopy (DCS) system based on two subharmonic optical parametric oscillators (OPOs) pumped by two phase-locked, tied to Rb clock, 1.93-µm thulium (Tm) combs. Each OPO spectrum consists of 350,000 spectral modes with 115 MHz intermodal spacing covering a wavelength range of 3.1-5.4 µm. Each mode linewidth and the uncertainty of the absolute frequency referencing (optical lock of Tm-combs to the 3kHz-linewidth 'RIO' laser at 1.56μm) do not exceed 50 kHz, which determines the spectral resolution. Massively parallel simultaneous detection of 22 molecular species with 115 MHz spacing was demonstrated earlier. Here, scanning the RIO reference laser, we continuously tune both combs with 50 kHz steps within 115 MHz interval, covering the entire 3.1-5.4 µm range at 50 kHz resolution, potentially providing up to 109 spectral data points in a single spectrum. The technique was verified by measuring the ν1+ν3 band of the CS2 molecule in 4.5–4.7 µm range with 15 MHz step, sufficient to resolve 981 strongest Doppler-broadened transitions of the CS2 molecule and its isotopologues. Most of the line intensities, accurately measured for the first time, are now included in HITRAN2020 database. |
Tuesday, May 31, 2022 4:06PM - 4:18PM |
E11.00009: Dissociation energy of the strontium van der Waals dimer Kon H Leung, Emily Tiberi, Brandon Iritani, Tanya Zelevinsky Alkaline-earth metals in the electronic ground state form weakly bound molecules due to the van der Waals attraction. The closed-shell nature of these molecules gives rise to narrow dipole-forbidden transitions between ground vibrational states that are insensitive to external fields. We leverage this to determine the dissociation energy of the strontium dimer (88Sr2), improving the measurement uncertainty by 5 orders of magnitude over early experiments with rare-gas matrices and heat-pipe ovens. We achieve this through frequency-comb-assisted Raman spectroscopy of the vibrational splitting between the absolute ground state and the least bound vibrational state, and two-color photodissociation to reference the binding energy of the latter with respect to the atomic threshold. |
Tuesday, May 31, 2022 4:18PM - 4:30PM |
E11.00010: Global Fits for AlCl, BiCl, and BiF: Benchmarks for Novel Physics Sean Jackson, Alexander Preston, Richard J Mawhorter New global fits combining existing rotational spectroscopy data for the Cl isotopologues of both AlCl (e.g. Hensel, et al. 1993 & Hoeft, et al. 1973) and BiCl (Kuijpers, et al. 1976) provide much improved precision in important molecular parameters for their use in novel physics applications, including hyperfine and Born-Oppenheimer Breakdown (BOB) terms. Another new fit combining data for a range of several rotational transitions in a number of vibrational states achieves similar results for BiF (Kuijpers & Dymanus 1977), providing another benchmark molecule for theoretical work on molecules used in eEDM and related searches. For example, uncertainties in the bismuth nuclear electric quadrupole eQq hyperfine values for BiF and BiCl are reduced by a factor of 3 and 8, respectively. The resulting precise ratios of the nuclear electric quadrupole moments Q(37Cl):Q(35Cl) for disparate AlCl and BiCl are quite consistent with each other as well as with further atomic and molecular spectroscopic measurements. This information bears directly on the oft-complicated nuclear physics reference work Q-value choices for both Cl isotopes. |
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