Bulletin of the American Physical Society
54th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 68, Number 7
Monday–Friday, June 5–9, 2023; Spokane, Washington
Session H05: Precision Spectroscopy - Experiment and Theory |
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Chair: Nicholas Hutzler, California Institute of Technology Room: 205 |
Wednesday, June 7, 2023 8:00AM - 8:12AM |
H05.00001: RF Measurement of the Hydrogen 2S Hyperfine Interval Ryan Bullis, Cory Rasor, William L Tavis, Scott Johnson, Michael Weiss, Dylan C Yost We will discuss a recent measurement of the hydrogen 2S hyperfine interval using Ramsey spectroscopy and a cryogenic atomic beam. This measurement reduces the experimental uncertainty by a factor of approximately eight as compared with the previous most precise measurement, which used optical spectroscopy of the 1S-2S transition [N. Kolachevsky, et al., Phys. Rev. Lett. 102, 213002 (2009)]. A linear combination of the 1S and 2S hyperfine intervals gives the quantity D21, which has been determined theoretically with high accuracy [Karshenboim and Ivanov, Eur. Phys. J. D 19, 13 (2002)]. Experimental comparisons of D21 with theory provide a stringent test of fourth order bound-state QED, and can be used as a probe of beyond Standard Model physics. |
Wednesday, June 7, 2023 8:12AM - 8:24AM |
H05.00002: Empirical determination of the hyperfine anomaly in cesium and improved tests of atomic theory in precision atomic searches for new physics Jacinda Ginges, George Sanamyan, Benjamin Roberts The finite distribution of the nuclear magnetic moment across the nucleus gives an important contribution to the hyperfine structure known as the Bohr-Weisskopf (BW) effect. We have obtained an empirical value of -0.24(18)% for this effect in the ground and excited s states of atomic cesium-133. This value is found from historical muonic atom measurements in combination with our muonic-atom and atomic many-body calculations. The effect differs by 0.5% in the hyperfine structure from the value found using the uniform magnetization distribution, which has been commonly employed in the community over the last several decades, and it supports the validity of the nuclear single-particle model. This result is important for the testing and development of atomic theory towards the 0.1% uncertainty level in precision atomic searches for new physics, in particular for atomic parity violation in cesium. |
Wednesday, June 7, 2023 8:24AM - 8:36AM |
H05.00003: Theoretical hyperfine splittings of $^{7,9}$Be$^{2+}$ ions for future studies of nuclear properties Zong-Chao Yan, Xiao-Qiu Qi, Pei-Pei Zhang, Ting-Yun Shi, G. W. F. Drake, Ai-Xi Chen, Zhen-Xiang Zhong The hyperfine structures of the $2,^3!S_1$ and $2,^3!P_J$ states of $^7$Be$^{2+}$ and $^9$Be$^{2+}$ are investigated within the framework of the nonrelativistic quantum electrodynamics, including relativistic and radiative corrections up to order $malpha^6$. The uncertainties of the calculated hyperfine splittings are on the order of tens of ppm, and for $^9$Be$^{2+}$ our results improve the previous theoretical and experimental values by at least two orders of magnitude. The improved sensitivity of the hyperfine splittings of $^{7,9}$Be$^{2+}$ to the nuclear Zemach radius and electric quadrupole moment opens the way to future measurements to extract the atomic physics values of these two nuclear properties to an accuracy of 5\% or better. |
Wednesday, June 7, 2023 8:36AM - 8:48AM |
H05.00004: Calculation of energies and hyperfine structure constants of $^{233}$U$^{+}$ and $^{233}$U Sergey G Porsev, Charles Cheung, Marianna Safronova With six valence electrons and a very heavy core, uranium represents a major challenge for precision atomic theory even using large-scale computational resources. |
Wednesday, June 7, 2023 8:48AM - 9:00AM |
H05.00005: Machine learning approach to configuration interaction Charles Cheung, Pavlo Bilous, Marianna Safronova High precision calculations of properties of complex atomic systems are a major challenge due to the exponential scaling of atomic configurations. We have developed a machine learning approach to identify the most important configurations out of a large set of configurations. Our method replaces the configuration interaction calculation for the complete set of configurations with a series of smaller ones performed on an iteratively expanding subset managed by a neural network. This results in significantly reduced computational memory requirements and reduced runtime. We also use this approach to evaluate the importance of the very large set of configurations, inaccessible with direct computation to solve previously intractable problems. |
Wednesday, June 7, 2023 9:00AM - 9:12AM |
H05.00006: Absolute frequency measurements of the D lines in 9Be+ using a single trapped ion. David Fairbank, Alessandro L Banducci, Robert Gunkelman, Jacob B VanArsdale, Megan Vildibill, Samuel M Brewer Optical frequencies of the D lines in 9Be+ were measured using single, laser cooled ions stored in a radio-frequency (rf) Paul trap. The spectroscopy laser was stabilized to an optical frequency comb and referenced to UTC(NIST). From these measurements, we extract the 2P fine-structure interval and 2P1/2 hyperfine constant with results which agree well with theory. The D2 measurement helps to resolve a 7σ discrepancy between previous trap-based measurements and one performed using co-linear laser spectroscopy. Effects relevant to precision measurements of strong transitions in ion traps are discussed, including quantum interference and motional heating due to photon scattering under intermediate confinement in the Lamb-Dicke regime. |
Wednesday, June 7, 2023 9:12AM - 9:24AM |
H05.00007: Observation of the 4f146s2 1S0-4f135d6s2(J=2) transition at 431 nm in ytterbium 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 to the variation of the fine structure constant, and experimental searches for this transition were ongoing. We observed this 431 nm transition in 171Yb atoms laser-cooled by a magneto-optical trap formed with the 6s2 1S0-6s6p3P1 intercombination transition at 556 nm. Some initial characterizations of the transition were performed. Presicion spectroscopy of this transition opens ways to new physics searches with isotope shift measurements and a search for the time-variation of the fine structure constant. |
Wednesday, June 7, 2023 9:24AM - 9:36AM |
H05.00008: High precision spectroscopy of light atoms for future tests of QED Karl J Ahrendsen, Chitose Maruko, Tilila Karani, Madison Whitmore, Will D Williams We report the most recent progress on high precision spectroscopic measurements from the Williams’ Lab at Smith College. We will report on excited-state spectroscopy measurements of oxygen, nitrogen, and beryllium transitions. For oxygen, we report on measurements of nine absolute transition frequencies between the 2s22p3(4S0)3p 5P states and the 2s22p3(4S0)3d 5D0 states. For nitrogen, we report on three absolute transition frequencies between the 2s22p2(3P)3s 2P states and the 2s22p2(3P)3p 2D0 states. For beryllium, we report on the absolute energy of the 2s3s 1S0 state. Combined with future theoretical predictions and experimental results, this work will serve as a test for quantum electrodynamics. |
Wednesday, June 7, 2023 9:36AM - 9:48AM |
H05.00009: Precision spectroscopy studies of radioactive molecules for fundamental physics Silviu-Marian Udrescu, Shane G Wilkins, Alex Breier, Ronald Fernando Garcia Ruiz, Michail Athanasakis-Kaklamanakis, Mia Au, Ivana Belosevic, Robert Berger, Mark L Bissell, Katerina Chrysalidis, Thomas E Cocolios, Ruben de Groote, Anais Dorne, Kieran Flanagan, Serge Franchoo, Konstantin Gaul, Sarina Geldhof, Thomas F Giesen, Dag Hanstorp, Reinhard Heinke, Agota Koszorus, Sonja Kujanpaa, Louis Lalanne, Gerda Neyens Precision molecular experiments provide a unique tool in the search for physics beyond the Standard Model (SM) and exploration of the fundamental forces of nature. Compared to atoms, certain molecules can offer more than eleven orders of magnitude enhanced sensitivity to violations of fundamental symmetries, enabling precision tests of the SM and the possibility to probe energy scales beyond hundreds of TeV. Containing octupole-deformed nuclei, radium monofluoride (RaF) is expected to be particularly sensitive to symmetry violating nuclear properties. In this talk, I will present the latest results obtained from a series of laser spectroscopy experiments performed on short-lived RaF molecules at the ISOLDE facility at CERN. Using a collinear resonant ionization setup, the rotational and hyperfine structure of 225RaF and 226RaF were measured with high precision. This allowed us to establish a laser cooling scheme for these molecules, and to explore nuclear structure effects at the molecular level. Our new results represent an increase in precision of almost 3 orders of magnitude compared to our previous studies, being the first of their kind performed on radioactive, short-lived molecules and opening the way for future precision studies and new physics searches in these systems. |
Wednesday, June 7, 2023 9:48AM - 10:00AM |
H05.00010: Precise measurement of the D2 S1(0) vibrational transition frequency Samuel A Meek, Arthur Fast Precise measurements of vibrational transition frequencies in isotopologues of molecular hydrogen provide a means to test fundamental physical questions and can also help determine physical constants more precisely. Many of the most precise measurements have focused on the heteronuclear isotopologue HD, which has comparatively strong dipole allowed vibrational transitions due to its slight asymmetry. These transitions are forbidden in the homonuclear isotopologues H2 and D2 due to their lack of a permanent dipole moment, and previous studies have instead focused on measuring their much weaker electric quadrupole transitions. In this talk, I will present a measurement of the D2 S1(0) vibrational transition frequency that circumvents this limitation. Instead of relying on the weak quadrupole moment to drive the transition, we instead apply a strong static electric field to induce a permanent dipole moment, enhancing the transition strength by a factor of nine. This approach can also be used to measure transitions with no electric quadrupole moment such as Q1(0), which is expected to be 19 times stronger than S1(0). |
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