Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session K66: General AMO Physics |
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Sponsoring Units: DAMOP Chair: Francisco Machado, ITAMP, Harvard-Smithsonian Center for Astrophysics Room: Room 413 |
Tuesday, March 7, 2023 3:00PM - 3:12PM |
K66.00001: VMC with ultra-compact, explicitly-correlated wave functions for the study of the Li isoelectronic sequence Daniel J Nader, Brenda M Rubenstein Variational Monte Carlo (VMC) is one of the simplest Quantum Monte Carlo (QMC) methods, which leverages random sampling to optimize the parameters of a given wave function. VMC is therefore a powerful tool for optimizing and evaluating the properties of explicitly-correlated wave functions. Explicitly-correlated wave functions are relatively simple, and therefore compact, and can be used as trial wave functions for more advanced quantum Monte Carlo methods. In this contribution, we optimize explicitly-correlated wave functions, with only seven nonlinear parameters, using VMC to describe the lowest quartet state (1s2s2p) of the Li isoelectronic sequence with nuclear charges between 3-10. The trial wave function is motivated by the exact solution for the limit case of infinite nuclear charge multiplied by exponentials with explicit dependence on relative distances between the electrons. The variational parameters admit an interpretation of screened electric charges as seen from the electrons. After the optimization, it is found that the compact wave function correctly describes the cusp conditions in the vicinity of the nucleus and that the variational parameters can be fit by quadratic functions of the nuclear charge. |
Tuesday, March 7, 2023 3:12PM - 3:24PM |
K66.00002: Exact energy eigenstates of the Coulomb-Stark Hamiltonian Seyedmohammad Yusofsani, Miroslav Kolesik We propose an approximation-free solution to the problem of an electron subject to a central Coulomb potential and a constant uniform electric field of high intensity i.e. the Stark-Coulomb problem. We introduce an algorithm to calculate the eigenstates of the Coulomb-Stark problem using a modest computational setup together with their proper normalization. Using this algorithm, calculating the Coulomb-Stark eigenstates is not harder than other special functions. |
Tuesday, March 7, 2023 3:24PM - 3:36PM |
K66.00003: Magnetic Control of Bound Electron Spins with Cavity-bunched Electron Beams Jakob Grzesik, Dominic Catanzaro, Dylan Black, Kenneth Leedle, Eric I Rosenthal, Joel England, Robert L Byer, Olav Solgaard, Jelena Vuckovic Advances in longitudinally structured electron beams have offered a new mode of materials investigation through merging the advantages of a spatial resolution of an energetic electron beam with the temporal resolution and spectral resolutions achievable by mode-locked lasers. Theoretical investigations on the interaction between a bound electron and a longitudinally bunched electron beam suggests that a properly structured beam may resonantly excite a bound electron, but the spatial extent of such an interaction remains unclear. We experimentally investigate the interaction between a longitudinally structured electron beam via cavity-based microbunching and report on its interaction with the bound electron spin in a diamond nitrogen vacancy center. |
Tuesday, March 7, 2023 3:36PM - 3:48PM |
K66.00004: Experimental Spectroscopic Data of SnO2 Powder and Films Investigated Over a Temperature Range of −193 °C to 400 °C Hawazin Alghamdi, Albert F Rigosi, Angela R Hight Walker, Prabhakar Misra Powders and films composed of Tin Dioxide (SnO2) are promising candidates for a variety of high-impact sensing applications; the material remains at high importance for demands of the industries that it would most benefit. Imaging techniques, such as atomic force microscopy (AFM) and scanning electron microscopy (SEM), were used in conjunction with X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS), to assess the structure and quality of the powder and film samples. Thermal effects associated with the vibrational features were determined by Raman spectroscopy over the temperature range −193 °C − 400 °C. We have observed a red-shift in the Raman spectra for the powder sample. The SnO2 powder peak shifts and FWHM features of spectra were consistent for both increasing and decreasing temperatures. |
Tuesday, March 7, 2023 3:48PM - 4:00PM |
K66.00005: Vibrational Characterization of Spatial Inhomogeneity of Single Surface-Adsorbed DMP Isocyanides Liya Bi, Amanda Chen, Krista Balto, Qingyi Zhu, Joshua Figueroa, Tod A Pascal, Shaowei Li We studied the site-dependent adsorption geometries and vibrational fingerprints of the 2,6-dimesitylphenyl (DMP) isocyanides on Au(111) with scanning tunneling microscopy (STM) and inelastic electron tunneling spectroscopy (IETS) at 5 K and 77K. The STM topographic images reveal that the DMP isocyanides preferably bind to the surface sites with a relatively large curvature, such as the step edges and the herringbone elbow sites. IETS measurement shows a series of molecular vibrational features which demonstrate obvious spatial inhomogeneity among molecules adsorbed at different sites. It was found that certain vibrational modes exhibit energy shifts upon altering the electric field between the tip and molecules, which was tentatively assigned to first-order perturbation to the Hamiltonian by coupling to the molecular dipole or the Stark effect. Furthermore, the varying energy shifts of the same vibrational modes at different sites could indicate a spatial variation of the molecular dipole moments due to different adsorption geometries. |
Tuesday, March 7, 2023 4:00PM - 4:12PM |
K66.00006: Recent Activities at the Merged-Beams Apparatus at Oak Ridge National Laboratory Arian G Dovald, Anjali Filinovich, Ac Hybl, Sean Ives, Timothy Suzuki, Vola M Andrianarijaona, Charles C Havener The merged-beams apparatus at Oak Ridge National Laboratory has been a successful technique for measuring the absolute cross sections of charge transfer from bare ions to atomic hydrogen, including recently results of N7+ and O7+ on atomic H [1]. The technique was also used to explore for the first time the fundamental system H2+ + H at low energy where vibrational effects were expected [2]. In addition, a cryogenic micro-calorimeter has been installed on the apparatus to study X-ray emission from charge transfer of solar wind ions interacting with He, H2, etc [3]. |
Tuesday, March 7, 2023 4:12PM - 4:24PM |
K66.00007: Solute segregation of Co in Al grain boundary structures with varying crystallographic character Lydia S Harris Serafin, Ethan R Cluff, Gus L Hart, Eric R Homer Solute segregation in materials with grain boundaries (GBs) is an area of interest in materials engineering in part due to its potential to stabilize the distribution of size and character of GBs. We lack a robust computational description of solute segregation in GBs. Recent studies of solute segregation in GBs have explored small subsections of the 5D space (Huber et al. npj Comp. Mat. 4, 64, 2018; Mahmood et al. Sci Rep. 12, 6673, 2022) or focused on polycrystalline structures (Wagih et al. Nat Comm. 11, 6376, 2020). We propose to explore trends across the entire 5D space using the dataset detailed in (Homer et al. Acta Mat. 234, 118006, 2022). We also plan to create a model of solute segregation that can predict segregation energy based on the local atomic environment of the atoms in the solute-free GB. |
Tuesday, March 7, 2023 4:24PM - 4:36PM |
K66.00008: Atom-Surface Interactions: New Perspectives Ulrich D Jentschura This talk will focus on a much-improved understanding of atom-surface interactions, which include both an improved understanding of the dielectric function of important classes of materials, as well as recent advances in the understanding of multipole corrections, which will be presented at the conference. On the side of the dielectric function, an example is given by a recent publication [Phys. Rev. B 106, 045202 (2002)] which addresses the temperature-dependent, dielectric function of intrinsic silicon and leads to a uniform description valid over wide temperature ranges. The results will be complemented, at the meeting, by new formulas for multipole corrections, as well as analytic expansions of atom-surface interactions which include distance-dependent Bethe logarithms which enter the logarihmic potentials. Applications to quantum reflection will also be outlined. |
Tuesday, March 7, 2023 4:36PM - 4:48PM |
K66.00009: Intense THz-Driven Dynamical Franz-Keldysh Effect in MAPbI3 Chia-Yen Lu, Wei-Hsuan Hsu, Ying-Ting Wang, Mei-Hsin Chen, Chan-Shan Yang*, Yu-Chieh Wen* Perovskites have attracted great attention due to the high conversion efficiency. In this work, we introduce and analyze the properties of dynamical Franz-Keldysh Effect in MAPbI3 by applying one strong THz electric filed with ~70 KV/cm and ~0.2 ps duration. At the THz frequencie of around 1.0 THz, we examine the properties of the near-bandgap optical MAPbI3 and the absorption spectrum which can be perfectly described by the DC Franz-Keldysh effect (DFKE). In other words, these findings aim to prove that a strong AC and time-dependent electric field has significantly alter the light absorption spectrum at the band edge in MAPbI3. |
Tuesday, March 7, 2023 4:48PM - 5:00PM |
K66.00010: Superoscillations Made Super Simple Gerard McCaul, Peisong Peng, Monica Martinez, Dustin R Lindberg, Diyar Talbayev, Denys I Bondar In ordinary circumstances the highest frequency present in a wave is the highest frequency in its Fourier decomposition. It is however possible for there to be a spatial or temporal region of the wave which locally oscillates at a still greater frequency, in a phenomenon known as superoscillation. Superoscillations find application in wide range of disciplines, but at present their generation is based upon constructive approaches which are difficult to implement. Here we address this, exploiting the fact that superoscillations are a product of destructive interference to produce a prescription for generating superoscillations from the superposition of arbitrary waveforms. As a first test of the technique, we use it to combine four THz laser fields generated by periodically poled Lithium Niobate. From this, we are able to predict and observe for the first time THz optical superoscillations in the temporal domain. The ability to generate superoscillations in this manner has potential application in a wide range of fields. It may for example contribute to the experimental realization of the complex pulses required by quantum control, and the generation of attosecond pulses without resorting to nonlinear processes. |
Tuesday, March 7, 2023 5:00PM - 5:12PM |
K66.00011: Atomic manipulation theory Mohamed K Ibrahim theory summary |
Tuesday, March 7, 2023 5:12PM - 5:24PM |
K66.00012: Linear String Theory for the single hole-doped Quantum Dimer Model Helene M. Lösl, Annabelle Bohrdt, Fabian Grusdt The single hole problem in a 2d quantum antiferromagnet (AFM) attracts attention due to its relevance for high-temperature superconductivity. A microscopic justification for describing mobile holes in an AFM background as bound spinon-chargon states is provided by Linear string theory (LST). For a spin liquid, it is instead often assumed that a hole can move freely through the spin background, which however lacks definite confirmation or refutation. Here, we thus investigate the motion of a single hole through a short-ranged resonating valence bond state as described by the quantum dimer model (QDM) on a square lattice. Therefore, we construct a new model Hamiltonian for the doped QDM where longer-range singlet states are allowed configurations and which explicitly features the string tension. The corresponding potential is calculated in the framework of LST for two different dopings. First, we consider a single chargon before extending the calculation to a spinon-chargon pair. This is done by explicitly calculating the energy of the string states at the Rokhsar-Kivelson point. We find that in both cases the energy increases linearly with the string length. |
Tuesday, March 7, 2023 5:24PM - 5:36PM |
K66.00013: Mode Resolved Protocol for Measuring the In-Plane Mode Temperatures in a 2D Ion Crystal in a Penning Trap Bryce B Bullock, Jennifer F Lilieholm, Allison L Carter, Matthew J Affolter, John J Bollinger Two dimensional crystals of 100's of ions in a Penning trap have demonstrated numerous promising results in quantum simulation and sensing. One recent result was the demonstration of electric field sensing of 240 ± 10 nV/m in 1 second, with sensitivity to motional displacements 8.8 ± 0.4 dB below the standard quantum limit. A fundamental limitation was 40 Hz fluctuations of the center of mass mode, believed to be in part caused by elevated in-plane mode temperatures of order 10 mK. We present a new experimental protocol to directly measure the in-plane temperature in the rotating frame of the crystal in a mode resolved way. Finally, we summarize ideas for improving the cooling of the in-plane modes. |
Tuesday, March 7, 2023 5:36PM - 5:48PM |
K66.00014: Physical insights from imaginary-time density--density correlation functions Tobias Dornheim The accurate theoretical description of the dynamic properties of correlated quantum many-body systems such as the dynamic structure factor S(q,ω) constitutes an important task in many fields. Unfortunately, highly accurate quantum Monte Carlo methods are usually restricted to the imaginary time domain, and the analytic continuation of the imaginary time density--density correlation function F(q,τ) to real frequencies is a notoriously hard problem. In this work, we argue that no such analytic continuation is required as F(q,τ) contains, by definition, the same physical information as S(q,ω), only in an unfamiliar representation. Specifically, we show how we can directly extract key information such as the temperature or quasi-particle excitation energies from the τ-domain, which is highly relevant for equation-of-state measurements of matter under extreme conditions. As a practical example, we consider ab initio path integral Monte Carlo results for the uniform electron gas (UEG), and demonstrate that even nontrivial processes such as the oton feature of the UEG at low density straightforwardly manifest in F(q,τ). In fact, directly working in the τ-domain is advantageous for many reasons and holds the enticing promise for unprecedented agreement between theory and experiment. |
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