Bulletin of the American Physical Society
2020 Fall Meeting of the APS Prairie Section
Volume 65, Number 22
Friday–Sunday, November 13–15, 2020; Virtual
Session C05: Parallel E |
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Chair: Pedro Rivero, Illinois Institute of Technology |
Sunday, November 15, 2020 1:15PM - 1:30PM |
C05.00001: Beam Delivery System for MAGIS-100 Jonah Glick, Noah Curfman, Kenneth Derose, Tejas Deshpande, Ben Garber, Stephen Hahn, Jason Hogan, Yijun Jiang, Jeremiah Mitchell, Robert Plunkett, Natasha Sachdeva, James Santucci, Linda Valerio, Yiping Wang, Timothy Kovachy MAGIS-100 is a 100 meter baseline atom interferometer which will search for wavelike dark matter and serve as a prototype gravitational wave detector in the 0.1-10 Hz frequency range. The interferometer will be assembled in the MINOS access shaft at Fermilab. As clouds of strontium atoms fall freely under gravity, a laser pulse mediated by a single photon transition on the Sr clock resonance will split the atom cloud wave function into a superposition of spatially distinct, phase coherent, momentum eigenstates. Each arm of the interferometer will accumulate phase proportional to its acceleration and, with subsequent pulses, the two states will be spatially recombined and imaged. The phase of the interference pattern produced is proportional to the local gravitational acceleration, certain systematic effects, and possible new physics. Important sources of noise for this instrument are jitter in the pointing of the interferometer beam, Doppler shifts which cause nonzero detuning, inhomogeneous laser phase and intensity profiles, temporal laser intensity and phase fluctuations, and fictitious forces emerging from the rotation of the earth. We present a design of the beam delivery system which compensates for these effects. [Preview Abstract] |
Sunday, November 15, 2020 1:30PM - 1:45PM |
C05.00002: Study of Wavefront Aberrations for MAGIS-100 Laser Beam Delivery System Yiping Wang, Natasha Sachdeva, Jonah Glick, Timothy Kovachy The MAGIS-100 experiment is a 100-m tall atom interferometer being built at Fermilab with a goal to measure gravitational waves in the mid-band frequency range of 0.1--10~Hz which is between the band for LIGO and LISA. For atom interferometry, pulses of light are used to create the atom optics equivalents of beam-splitters and mirrors. Laser wavefront aberrations cause phase distortions across the Sr atom cloud and result in loss of contrast and systematic errors in the interferometer phase. In this talk, we present simulation studies of the propagation of laser beam perturbations through the MAGIS-100 laser beam delivery system in order to determine the beam aberrations at the locations of the atoms. The effect of these aberrations are simulated by numerically evaluating the Rayleigh-Sommerfeld diffraction integral using the FFT convolution theorem. We studied spatial filtering of the beam by free-space propagation in the MAGIS-100 beam delivery system and the effects of specific aberrations such as localized defects and spherical aberrations in optical components. These simulations informed a design of the beam delivery system that minimizes the aberrations experienced by the atoms. [Preview Abstract] |
Sunday, November 15, 2020 1:45PM - 2:00PM |
C05.00003: Channel Competition in Single Ionization of CS$^+$ by Intense Laser Pulses Tiana Townsend, E. Wells, Bethany Jochim, T. Severt, K.D. Carnes, I. Ben-Itzhak Employing a coincidence three-dimensional momentum imaging technique, we investigate the ultrafast, intense laser-induced ionization of CS$^+$. The analysis presented here focuses on the intensity-dependent branching ratio from 3$\times$10$^{14}$ to 3$\times$10$^{16}$ W/cm$^2$. The charge-symmetric C$^+$ + S$^+$ channel is dominant at all measured intensities, followed by CS$^{2+}$ and then C + S$^{2+}$, while C$^{2+}$ + S is not observed. The branching ratio measurement is assisted by {\it in situ} determination of the detection efficiency of all the product channels. [Preview Abstract] |
Sunday, November 15, 2020 2:00PM - 2:15PM |
C05.00004: Molecular rotational movies captured with KeV ultrafast electron diffraction Yanwei Xiong, Kyle Wilkin, Martin Centurion Ultrafast electron diffraction (UED) measurements of isolated molecules have been a powerful tool to study structural dynamics during molecular reactions induced by an ultrafast laser pulse. The molecular wave packet motion can be retrieved with sub-Angstrom resolution from the two-dimensional electron diffraction patterns by the Fourier transform, followed by the Abel inversion. We use a 90-keV high-repetition rate table-top UED setup to capture a time-series of diffraction patterns from nitrogen molecules impulsively aligned by a femtosecond laser pulse. Based on the experimental data, we have retrieved an essentially continuous real-space movie of the rotational motion with high resolution and captured the initial alignment and multiple revivals. [Preview Abstract] |
Sunday, November 15, 2020 2:15PM - 2:30PM |
C05.00005: Switching electromagnetically induced transparency via chiral optical states at exceptional points Changqing Wang, Lan Yang Electromagnetically induced transparency (EIT) is a quantum interference effect that renders an opaque medium transparent with the presence of strong coherent light. Associated with EIT is a strong reduction of the group velocity of light in the medium, which enables extensive applications in slow-light generation, optical storage and quantum memory. Recently, unconventional physical properties of open systems have been widely studied especially around the non-Hermitian singularities, i.e., exceptional points (EPs), where the eigenvalues and the eigenstates of the non-Hermitian systems become degenerate. Here we present a novel way of controlling the EIT process in optical resonator systems by exploiting chiral optical states at the EPs. Optical interference can be switched on and off by tuning one resonator to two different types of EPs with opposite chirality, which enables the switch between EIT and absorption. This novel routes for EIT control leveraging non-Hermitian degeneracies will shed new light on the engineering of slow light and optical memory. The state control approach which is compatible with quantum gate operation may build up a connection between quantum information processing and quantum memory. [Preview Abstract] |
Sunday, November 15, 2020 2:30PM - 2:45PM |
C05.00006: Progress towards Ultrasensitive Gravity Gradiometers using Macroscopically Delocalized Strontium Kenneth DeRose, Natasha Sachdeva, Tejas Makarand, Jayampathi Kangara, Yiping Wang, Jonah Glick, Timothy Kovachy Recent precision measurements based on torsion balances and pendulums disagree on the gravitational constant G by nearly 40 times the smallest reported uncertainty [1,2]. To address this discrepancy, it is important to measure G with a variety of different methods. Quantum sensors based on atom interferometry have proven to be a powerful tool for measuring G, with a different set of systematic errors than the classical techniques used in most measurements [2]. Here, we discuss progress toward a new atom interferometric measurement of G that will leverage recent advances in ultrasensitive atomic gravity gradiometers. We will detail our designs and progress toward the construction of a two-meter fountain capable of delocalizing atomic wavefunctions on a macroscopic scale by utilizing recent advances in large momentum transfer on the strontium transitions. We intend to test our gravity gradiometer with two large single-crystal silicon proof masses. The masses will translate on thick, level granite slabs between measurements where a high-resolution atomic phase readout will allow the determination of G. In addition, the apparatus will be used to test the gravitational inverse square law in order to search for new particles beyond the standard model. [1] A. Mann. PNAS 113, 9949-9952 (2016); Q. Li et al., Nature 560, 582-588 (2018). [2] G. Rosi, F. Sorrentino, L. Cacciapuoti, M. Prevedeli, and G. M. Tino, Nature 510, 518 (2014). [Preview Abstract] |
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