Bulletin of the American Physical Society
88th Annual Meeting of the Southeastern Section of the APS
Volume 66, Number 16
Thursday–Saturday, November 18–20, 2021; University Center Club, Florida State University, Tallahassee, Florida
Session A03: Atomic Molecular and Optical Physics I |
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Chair: Michael Chapman, Georgia Tech Room: Stadium |
Thursday, November 18, 2021 9:30AM - 10:00AM |
A03.00001: Precision Atomic Mass Measurements of Light Ions Invited Speaker: Edmund Myers The atomic masses of the proton, deuteron, triton and helion (nuclei of hydrogen, deuterium, tritium and helium-3) are regarded as fundamental constants impacting wide areas of physics. In particular, a high-precision value for the difference in mass between tritium and helium-3 is needed for testing systematics in the ongoing KATRIN neutrino mass experiment, while the mass ratio of the deuteron to proton is important for interpreting the results of recent, high-precision laser and terahertz spectroscopy of the HD$^{+}$ molecular ion. This leads to an improved electron-proton mass ratio and limits on a hypothetical Angstrom-scale nucleon-nucleon force. At FSU we measure precision mass ratios by simultaneously trapping the two ions in a Penning trap. Our measurements of mass-3 ions, besides providing an important datum for KATRIN, revealed significant errors in the previously accepted masses of p, d and h. They also provided an experimental demonstration of metastable, high-$J,K$ rotational levels in the H$_{3}^{+}$ ion. Recently we have been able to place two ions in a coupled magnetron orbit and measure their cyclotron frequencies simultaneously, suppressing the effect of variation in the magnetic field several orders of magnitude. Using this technique with a deuteron and a H$_{2}^{+}$ ion we have been able to resolve molecular vibrational energy, and partly resolve rotational energy, as mass changes of the H$_{2}^{+}$. This resulted in the first light-ion mass ratio with an uncertainty 5 x $10^{-12}$, a value for $m_{d}/m_{p}$ at 5 x $10^{-12}$, and an atomic mass of the proton at $10^{-11}$. [Preview Abstract] |
Thursday, November 18, 2021 10:00AM - 10:15AM |
A03.00002: Positron elastic scattering by semifilled-shell atoms: the $e^{+}+ \rm{Mn}$ case Valeriy Dolmatov, Miron Amusia, Larissa Chernysheva Atoms with semifilled shells are special atoms because they possess the highest spin multiplicity among other atoms from the same raw of the periodic table. The current knowledge of positron elastic scattering by atoms with multielectron semifilled shells is lacking. We provide the first initial knowledge on this process. As a case study, we focus on positron elastic scattering of a semifilled-shell Mn($...3d^{5}$$4s^{2}$, $^{6}S$) atom. Scattering phases and total cross sections are calculated and scrutinized. Electron correlation is accounted for in the frameworks of the self-energy part of the positron's Green function and the RPAE theory. The ``spin-polarized'' Hartree-Fock approximation is chosen as the zeroth-order approximation. We also account for the formation of virtual Ps and its impact on the scattering process in a simplified but fairly good approximation, as in Amusia \textit{et al.}, Elastic scattering of slow positrons on atoms, \textit{JETP} \textbf{97} $34$ ($2003$). We unravel the specificity of the impacts of both the virtually formed Ps and electron correlation on $e^{+}+ \rm{Mn}$ elastic scattering. The spectacular differences between the electron and positron scattering by Mn are revealed and interpreted as well. [Preview Abstract] |
Thursday, November 18, 2021 10:15AM - 10:30AM |
A03.00003: Absolute nuclear radii of Ir isotopes determined by EUV spectroscopy of highly charged Os and Ir Adam Hosier, Fnu Dipti, Roshani Silwal, Alain Lapierre, Steve Blundell, Samuel Sanders, Yang Yang, Paul Szypryt, Joseph Tan, Aung Naing, John Gillaspy, Joan Dreiling, Gerald Gwinner, Antonio Villari, Yuri Ralchenko, Endre Takacs The absolute nuclear radius of iridium isotopes can be determined and improved through the relative nuclear radii difference between osmium and iridium using a novel approach in intensive, high statistics EUV spectroscopy. The electron beam ion trap (EBIT) at NIST was used to produce highly charged ions of Os and Ir with a beam energy of about 18 keV. The spectra from electron impact excitations were recorded over a range of 4.05 nm to 19.95 nm with a flat-field grazing EUV CCD spectrometer with a pixel resolution of about 0.005 nm. Observed transitions were Na-like 3s -- 3p$_{1/2}$ and the Mg-like 3s$^{2}$ -- 3p$_{1/2}$ of both Os and Ir. The shifts in the wavelength between the corresponding Ir and Os transitions were measured continuously over the course of several days by cycling the injection of Os, Ir, and Ne (used for calibration) into the EBIT. The wavelength shifts measured with our experimental accuracy are directly related to with the difference of the mean square radii through the expansion of the nuclear Seltzer moment. Calculation of necessary nuclear parameters were performed by GRASP2K $^{[}$and RMBPT packages. [Preview Abstract] |
Thursday, November 18, 2021 10:30AM - 10:45AM |
A03.00004: Development of Chip Platform Magneto-Optical Traps Integrating Machine Learning Techniques for Testbed Parameter Optimization Alexandra Crawford, Luke Bemish, Spencer Olson, Chandra Raman The process of miniaturizing atomic experiments and developing chip-platform integrated techniques to effectively slow and trap atoms is a step towards making compact atomic clocks and inertial sensors for commercial use. Integrating Machine Learning (ML) techniques to improve the rigidity and stability of the testbed also provides the ability to continually optimize the system parameters based on fluctuating environmental conditions. This project contains two related setups that approach the same problem from two different directions. 1) A ColdQuanta RuBECi platform looks to integrate new compact electronics and home-built software to implement ML techniques for parameter optimization of a commercial product. Assembly of the platform and implementation of the optimization software to properly develop ML libraries will be discussed. 2) A business card-sized double magneto-optical trap system is a developmental approach to the chip-scaling of a Bose-Einstein Condensate (BEC) generating platform for atomic interferometry, where future ML implementation will enable autonomy from a controlled laboratory environment. Manufacture and assembly of the Business Card platform will also be discussed. [Preview Abstract] |
Thursday, November 18, 2021 10:45AM - 11:00AM |
A03.00005: Resolving the Ro-Vibrational State of Single H$_2^+$ Ions to Increase the Precision of a Cyclotron Frequency Ratio Measurement of H$_2^+/$D$^+$ David Fink Redevelopment of a technique of simultaneous cyclotron frequency measurement [1] has allowed us to measure the cyclotron frequencies of H$_2^+$ and D$^+$ with enough mass resolution to differentiate (using the mass-energy relation) between vibrational states of the H$_2^+$ ion in a few hours of data taking. By repeated measurements over several weeks we have tracked the ro-vibrational decays of single H$_2^+$ ions to the vibrational ground state, and, in some cases, identified specific rotational levels. This allowed us to more precisely correct the measured H$_2^+/$D$^+$ mass ratios for H$_2^+$ rotational energy, which was the largest source of uncertainty in our previous measurement of the H$_2^+/$D$^+$ CFR [2]. Details of the ro-vibrational analysis will be presented along with final results for a deuteron-to-proton mass ratio [3]. [1] S. Rainville, J. K. Thompson and D. E. Pritchard, Science 303, 334 (2004). [2] D. J. Fink and E.G. Myers, PRL 124, 013001 (2020). [3] D. J. Fink and E. G. Myers, submitted to Phys. Rev. Lett. [Preview Abstract] |
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