Bulletin of the American Physical Society
APS April Meeting 2022
Volume 67, Number 6
Saturday–Tuesday, April 9–12, 2022; New York
Session H08: Precision Tests of Physics Laws IIRecordings Available
|
Hide Abstracts |
Sponsoring Units: GPMFC Chair: Tim Kovachy, Stanford University Room: Juilliard |
Sunday, April 10, 2022 10:45AM - 10:57AM |
H08.00001: Polyatomic Molecules for Fundamental Symmetries and Quantum Science Nicholas R Hutzler Polyatomic molecules offer unique advantages to precision measurement, quantum sensing, and fundamental physics as they can be engineered to match the needs of a wide range of scientific goals. In particular, they can combine the intrinsic sensitivity of polar molecules to fundamental symmetry violations with the ability to implement advanced quantum control methods. This provides a pathway to improvements by orders of magnitude in sensitivity to both leptonic and hadronic CP-violation, and other sources of physics beyond the Standard Model. This talk will present an overview of experimental and theoretical work in our lab toward this end, including experimental searches for the electron EDM and nuclear magnetic quadrupole moments, and theoretical work designing polyatomic molecules containing exotic nuclei to explore fundamental nuclear physics and novel structures to provide new tools for quantum sensing. |
Sunday, April 10, 2022 10:57AM - 11:09AM |
H08.00002: Neutrality of matter search with levitated microspheres Nadav Priel, Alexander Fieguth, Charles P Blakemore, Emmett Hough, Akio Kawasaki, Denzal Martin, Gautam Venugopalan, Giorgio Gratta It is commonly accepted that the charge of the electron is equal in magnitude to the charge of the proton. This observation has been tested with great precision over the last century and has supporting arguments from the theory side. However, the measurement of this equality is a sensitive tool to probe new physics as it is breaking down in few suggested extensions of the standard model. We report on a neutrality of matter test conducted with optically levitated microspheres. In this test, the electrostatic response of a micron size sphere with an equal number of protons and electrons is measured with very high sensitivity. This technique is complementary to other methods used to test matter neutrality in the past. The current sensitivity is not due to fundamental physical limitations and ongoing improvements of the system targeting better background mitigation and modeling, together with improved force sensitivity, are expected to further extend the parameter space covered by the technique. |
Sunday, April 10, 2022 11:09AM - 11:21AM |
H08.00003: Ultra-sensitive momentum detection using levitated microspheres Jiaxiang Wang, Fernando Monteiro, Gadi Afek, Benjamin Siegel, Molly Watts, Theophilus L Human, Juan Recoaro, Sarah Dickson, David Moore Searching for small momentum transfers to micron-scale sensors is a promising approach to search for dark matter and to enable spectroscopy of nuclear decays in small particles. Levitated sensors can minimize thermal noise and have been shown to reach acceleration sensitivity as low as ~100ng/sqrt(Hz). These sensors also allow the detection of small momentum impulses. Applications of these techniques will be described, including searches for asymmetric dark matter recoils from the optically trapped sensors, as well as the mechanical detection of single nuclear decays with a momentum threshold <50MeV/c. |
Sunday, April 10, 2022 11:21AM - 11:33AM |
H08.00004: Towards levitated, macroscopic-scale atom interferometry with strontium for precision gravity gradiometry Natasha Sachdeva, Zilin Chen, Kenneth DeRose, Tejas Deshpande, Jonah Glick, Kefeng Jiang, Sharika Saraf, Yiping Wang, Tim Kovachy Light-pulse atom interferometry is a versatile and powerful tool for conducting precise measurements of fundamental constants, testing general relativity, searching for signatures of new physics, and investigating quantum mechanics on a macroscopic scale. For atom interferometry, pulses of light are used to create the atom optics equivalents of beam-splitters and mirrors. Recent advances in atomic clocks have illustrated the advantages of using strontium, an alkali-earth atom, over the typically used alkali atoms due to its decreased sensitivity to backgrounds such as magnetic fields. We present progress toward the realization of a two-meter atomic fountain at Northwestern University that will be used to develop atom interferometry with large spatial separations between the clouds and long interrogation times by levitating the atoms using optical lattices. The two meter fountain will be used for precision gravitational measurements such as a measurement of the gravitational constant G and for a precise test of the inverse-square law for gravity. |
Sunday, April 10, 2022 11:33AM - 11:45AM |
H08.00005: Towards a better determination of big G Muchuan Hua, Emily N Ord, Evan Liang, Marvin Q Jones, Grace C Mattingly, Hilde F Isachsen, Rutuj Gavankar, Nicholas Fuller, Ian S Guerrero, William M Snow, Charles D Hoyle, Stefan W Ballmer, Ricardo S Decca The Newtonian gravitational constant G is ill determined when compared to other universal constants due to its extremely weak interaction strength. Meanwhile, more questions are raised in the accuracy among the G measurements as results disagree with each other. To improve both the measurement accuracy and precision of G, a new apparatus based on the angular-acceleration-feedback torsion pendulum system was designed and assembled in IUPUI. The idea is to reveal potential unknown systematic errors by allowing three different methods (i) the time-of-swing method with large amplitudes, (ii) extracting the resonance frequency of the pendulum through noise measurements and (iii) the angular-acceleration feedback method to be carried out in the apparatus. A precision of 2 ppm is expected to be achieved by increasing the system size to reduce the error introduced by metrological uncertainties. System characterization data and preliminary results will be shown in the presentation. |
Sunday, April 10, 2022 11:45AM - 11:57AM |
H08.00006: Tilt Control System for Tests of Gravity Under 50 Microns Claire J Rogers, Alyssa M Johnson, Michael E Gengo, Jesse P Mendez, Emily N Ord, Charles D Hoyle Undergraduate researchers and faculty at Humboldt State University are conducting tests of gravity at distances under 50 microns with the goal of searching for violations of the Inverse Square Law of gravity or the Weak Equivalence Principle. Violations of either of these principles could support models attempting to unify the Standard Model and General Relativity. The short-range gravity tests at Humboldt State University are being conducted using a torsion pendulum with equal masses of aluminum and titanium arranged as a composition dipole and a sinusoidally oscillating copper attractor mass in a parallel-plate arrangement. Due to the sensitivity of these tests, environmental effects such as the thermal conditions of the laboratory, electrical and magnetic fields from the environment and surrounding systems, and the tilt of the building housing the apparatus all must be understood and reduced as much as possible. We have implemented various systems to reduce the noise from each of these sources as much as possible. In this talk we will describe the ways in which the motion of the laboratory building affects our measurements and a system developed to actively level the apparatus to reduce tilt-related effects. |
Sunday, April 10, 2022 11:57AM - 12:09PM |
H08.00007: Capacitance Alignment for Future Yukawa Interaction Experiment Thomas Bsaibes, Ricardo S Decca Yukawa-like interactions arising from hypothetical new bosons are poorly constrained below 1 μm. Using a 500 μm long cylinder with a radius of 150 μm instead of a spherical test mass, we will further improve the limits on Yukawa-like interactions in the sub-micron regime by an order of magnitude. However, to perform a successful experiment the orientation of the cylindrical test mass with respect to a planar source mass needs to be determined to within 3 nm. A scheme is being developed to use the capacitance between the cylinder and the planar source mass to determine the cylinder's relative position and orientation. The method is currently being tested on a scaled up system comprising a 5 cm long brass cylinder with a diameter of 5 cm, standing in for the test mass, and a brass plate acting as the planar source mass. On this scale the position needs to be known to within 1000 nm and the angle to within 100 μrads to ensure that in the final application the position is known to within 3 nm and the angle to within 1 μrad. The strategy involves comparing actual capacitance measurements to capacitance values obtained from a COMSOL simulation with the cylinder in different positions. In this presentation I will show the progress made in using capacitance as an alignment indicator. |
Sunday, April 10, 2022 12:09PM - 12:21PM |
H08.00008: Parity-mixed coupled-cluster formalism for computing 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. |
Sunday, April 10, 2022 12:21PM - 12:33PM |
H08.00009: Search for the Expected Radiation due to Photoejection of an Inner Shell Electron Carl Franck, Philip Jacobson, Andrija Rasovic, Arthur Campello Pratt et al have called attention to the unsettled observational status for the radiation (intraatomic bremstahllung, IAB) expected upon the photoejection of inner shell electrons. We tested for such radiation in the 3 to 7 keV band produced by photoelectrons from the K shell of a copper target upon absorption of an incident 46 keV photon. Exploting a prediction for the major background process: ordinary bremsstrahlung due to the encounter of the photoelectron with atoms other than that of its point of origin, we conclude that for our thinnest (40 nm) targets within statistical limits we observe no IAB radiation. In this manner, contemporary theory is ruled out by over 5 sigmas. Assuming no particular secondary process the intensity of observed IAB radiation is 4 sigmas below expectations. We conclude that in contrast to the sister nuclear process of internal bremsstrahlung observed upon beta decay, our understanding of intratomic bremsstrahlung remains lacking. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700