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 CCC03: V: General Physics III |
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Sponsoring Units: APS Chair: Ramakrishna Podila, Clemson University Room: Virtual Room 3 |
Wednesday, March 22, 2023 3:00PM - 3:12PM |
CCC03.00001: Differentiable Gaussian Process Force Constants Keerati Keeratikarn, Jarvist M Frost Gaussian processes are one machine learning method to describe Potential Energy Surfaces (PESs). Gaussian processes are naturally Bayesian (probabilistic). |
Wednesday, March 22, 2023 3:12PM - 3:24PM |
CCC03.00002: Cluster Spin Glass State and Observation of Giant Exchange Bias in Tetragonal Mn-Ni-Sn Heusler Alloys: Experiment and Theory Jyoti Sharma, K. G Suresh, Aftab Alam We have done a combined experimental and Density functional theoretical (DFT) study of the exchange bias (EB), structural and magnetic properties of Mn rich Mn50Ni41.5+xSn8.5-x Heusler alloys. These alloys were synthesized experimentally by arc melting method, and found to possess the tetragonal structure at room temperature (RT) with increasing tetragonal distortion with x. DC magnetization (M vs. T) measurements have suggested that the martensitic transition occur above RT for all the compositions. A large splitting between zero field cooling (ZFC) and field cooled cooling (FCC) M vs. T curves is observed at low temperatures, which is a suggestive of the coexistence of AFM/FM or spin glass/FM or ferrimagnetic phases. DFT simulation on off-stoichiometric Mn50Ni42.1875Sn7.8125 alloy (nearly exp. composition) predicts the tetragonal structure with the ferrimagnetic ground state, which is in good agreement with the experimental results. These alloys are found to exhibit giant exchange bias at low temperatures, with a maximum EB field of around 7100 Oe at 2 K for x=1, which is significantly larger than that reported for any other tetragonal Heusler systems. Frequency dependence of spin freezing temperature on scaling law through AC susceptibility measurements confirms the presence of cluster spin glass (CSG) like state in these alloys. CSG state has also been confirmed from the memory and aging effects recorded in various ZFC and FC protocols. Such a large EB is attributed to the strong exchange coupling between the CSG clusters embedded in an otherwise ferrimagnetic matrix. The exchange mechanism behind the EB effect has been verified in the light of varying bond lengths between different magnetic atoms and hence the magnetic coupling, due to the large tetragonal distortion. Thus, the present study provides not only an insight into the complex magnetism of the ground state of Mn rich tetragonal Heusler alloys but also facilitates in search of new Heusler systems in this family with enhanced physical properties, from fundamental as well as application point of view. |
Wednesday, March 22, 2023 3:24PM - 3:36PM |
CCC03.00003: Mapping AC Susceptibility with Quantum Diamond Microscope Shishir Dasika, Madhur Parashar, Kasturi Saha Measurement of AC susceptibility is critical and indispensable in investigating magnetic |
Wednesday, March 22, 2023 3:36PM - 3:48PM |
CCC03.00004: Characterizing Field-Dependent Strength and Orientation of Superparamagnetic Bead Magnetization Via DNA Origami Microlevers Stephanie Lauback, Dylan Roderick, Khadija Hamisi, Linnea Larson, Abigail Gilreath, Kayla Loescher, Avery Buchanan, Ratnasingham Sooryakumar Many advancements in biomedical and nanotechnologies have been realized through the ability to precisely control the spatial and temporal movement of micro- and nano-actuators using superparamagnetic beads. Despite the range of applications, the nature of the magnetization of the MyOne Dynabeads has not been fully investigated. To quantify the torque on superparamagnetic beads in precessing external magnetic fields, it is important to understand how the individual magnetic dipoles within a bead respond to the changing magnetic fields. This research establishes a novel approach to investigate the field-dependent magnetization of individual MyOne Dynabeads for external fields between 10 Oe to 100 Oe. To overcome the challenges of tracking the movement of single beads, the bead is tethered to the surface through attachment to a stiff DNA microrod which is assembled using the DNA origami technique. By applying in-plane external fields to the DNA-rod tethered beads, the strength and orientation of the magnetization can be determined from the response and thermal fluctuations of the bead. Preliminary results show that there are two contributing factors to the net magnetic moment: the permanent moment which dominates at lower fields, and the induced anisotropic component which dominates at higher fields. |
Wednesday, March 22, 2023 3:48PM - 4:00PM |
CCC03.00005: Preparing angular-momentum eigenstates by quantum walk on su(2)×su(2) algebra Yuan Shi, Kristin M Beck, Michael K Kruse, Jonathan L DuBois, Stephen B Libby To enable quantum computation of atomic and nuclear physics problems, we develop an efficient state preparation scheme for combining two angular momenta J1 and J2 to form eigenstates of their total angular momentum J=J1+J2. Compared to a brute force approach, which performs the basis change using O(j3) nonzero Clebsch–Gordan (CG) coefficients, our scheme prepares the |j,m>eigenstate using quantum walk with O(j) steps generated by su(2)×su(2) algebra. To prepare states deterministically, we choose a series of evolution Hamiltonians, each is sparse and confines the quantum walk to a two-dimensional Hilbert space. We encode the ground state as the top state |j1+j2, j1+j2>. When m ≥ 0, our scheme walks the state from |j'+1, m'+1>to |j',m'>until j'=j. Then, keeping j constant, another series of walks moves |j,m'+1>to |j,m'>until m'=m. Analogously, when m<0, a series of steps reaches the desired final state from the bottom state |j1+j2, -j1-j2>after swapping it with the ground state. We test our state preparation scheme on classical computers, reproducing known CG coefficients, and implement small test problems on current quantum hardware. The state preparation scheme paves the way towards quantum calculation of full matrix elements. |
Wednesday, March 22, 2023 4:00PM - 4:12PM |
CCC03.00006: Coupling Rydberg atoms to a superconducting millimeter-wave resonator: quantum transduction and progress towards spin-squeezing Lavanya Taneja, Aishwarya Kumar, Zeyang Li, Aziza Suleymanzade, Mark J Stone, David Schuster, Jonathan Simon High quality factors of superconducting resonators and strong atomic transitions in the millimeter-wave and microwave regime can enable strong interactions in a neutral atom cavity-QED system. Our platform features a unique 3D superconducting millimeter-wave resonator at 5 K intersecting with an optical Fabry-Perot cavity, allowing for atoms at the intersection to interact with both cavities simultaneously. Harnessing the strengths of our system, we recently demonstrated quantum transduction between mm-wave photons and optical photons using Rydberg atoms. The interactions between the mm-wave cavity and atoms can also enable spin-squeezing on the ground-Rydberg transition, with potential applications for entanglement-enhanced quantum sensing and metrology. In the talk, I will describe our platform and present recent transduction results from the experiment. I will also discuss our efforts towards spin squeezing, including our plans to upgrade to colder resonator temperatures for stronger atom-cavity coupling. |
Wednesday, March 22, 2023 4:12PM - 4:24PM |
CCC03.00007: Effects on the electronic and magnetic transitions by light in CdS/La0.7Sr0.3MnO3 heterostructures Henry Navarro, ALI C BASARAN, Fernando Ajejas, Lorenzo Fratino, Soumen Bag, Tianxing D Wang, Erbin Qiu, Victor Rouco, Isabel Tenreiro, Felipe Torres, Alberto Rivera, Jacobo Santamaria, Marcelo J Rozenberg, IVAN K SCHULLER The strongly correlated material, La0.7Sr0.3MnO3 (LSMO) exhibits a metal-to-insulator (MIT) coincidental with a magnetic transition near room temperature. Although the physical properties of LSMO can be manipulated by strain, chemical doping, temperature, or magnetic field, they often require large external stimuli. In order to add additional flexibility and tunability we developed a hybrid optoelectronic heterostructure, that uses photocarrier injection from cadmium sulfide (CdS) to an LSMO layer to change its electrical conductivity. Although LSMO exhibits no significant optical response, our ultra-thin CdS/LSMO heterostructures show an enhanced conductivity, with ~ 37 % resistance drop, at the transition temperature under light stimuli. This enhanced conductivity in response to light is comparable to the effect a 9 T magnetic field in pure LSMO. Surprisingly, the optical and magnetic responses of our heterostructures showed different effects when both stimuli are applied. This shows that incorporation of quantum materials into heterostructure may provide the means to add new functionalities. |
Wednesday, March 22, 2023 4:24PM - 4:36PM |
CCC03.00008: Quantum fluctuation of ferroelectric order in polar metals Fangyuan Gu Since its discovery in less than a decade ago, "polar metallic phase" has ignited significant research interest, as it further functionalizes the switchable electric polarization with additional electric transport capability, granting them great potential in next-generation electronic devices. The polar metallic phase is a metallic phase of matter containing long-range ferroelectric order in atomic position, typically found in carrier-doped FE materials. Distinct from the typical FE insulating phase, this phase hosts FE order as a spontaneous inversion symmetry breaking in the absence of global FE polarization. Unexpectedly, FE order is found to be dramatically suppressed by metallic carriers and destroyed at only moderate ∼ 12% carrier density. Here, we propose a general mechanism based on carrier-induced quantum fluctuations to explain this puzzling phenomenon. Owing to their kinetic energy, quantum carriers can be strongly dressed by a polarizable medium and form polaronic quasi-particles, inside which the local FE correlation is disrupted. Consequently the long-range FE order must diminish before the size and density of the polarons is large enough to disconnect the remaining FE-allowed region. We demonstrate such polaron formation and its kinetic-driven growth via a simple model using exact diagonalization, perturbation and quantum Monte Carlo approaches. This proposed quantum mechanism also provides an intuitive picture for many unexplained experimental findings, which can facilitate new designs of multifunctional FE-electronic nanodevices through additional quantum effects. |
Wednesday, March 22, 2023 4:36PM - 4:48PM |
CCC03.00009: A Solvable Model for Discrete Time Crystal Enforced by Nonsymmorphic Dynamical Symmetry Ziang Hu, Bo Fu, Shun-Qing Shen Discrete time crystal is a class of non-equilibrium quantum systems that exhibits subharmonic response to periodic driven. In this paper, we propose a kind of discrete time crystal enforced by nonsymmorphic dynamical symmetry. When a system hosts certain nonsymmorphic dynamical symmetry, the symmetry will enforce the instantaneous states Mobius twisted and double the period of the instantaneous state. When the evolution speed of the system equals proper parameters, or the system is in the long-period limit, it will spontaneously exhibit a period expansion without undergoing quantum superposition states. The system also hosts a half-integer topological invariance and a pi Berry phase after two periods of evolution. |
Wednesday, March 22, 2023 4:48PM - 5:00PM |
CCC03.00010: Unambiguous Empirical Evidence of a Nonlocal Superdeterministic Universe Manuel S Morales The entirety of what we call the universe consists of two mutually exclusive and jointly exhaustive fundamental domains: existence, and nonexistence. As understood in academia and generally practiced in science, the domain of existence is used to obtain internal and external validity from within the same domain. The bias of existence causation is such that the domain of existence is understood to be a self-causal closed system thus conserved. However, unambiguous empirical evidence has confirmed that the domain of nonexistence gives rise to predetermined variables that can only come-to-exist, not preexist or be existent. Without the nonlocal variables of motion, direct and indirect selection, it is mechanically impossible for any local experiment to be conducted. The findings also revealed that experiments that fail to account for the hidden variables of motion are subject to false-positive and false-negative empirical results. Note, the predetermined laws of a superdeterministic universe can be tested by all human beings via the Final Selection Experiment for absolute external validity. Therefore, to advance from the bias of using the mechanics of existence causation, e.g., classical mechanics and quantum mechanics, to hide the fundamental mechanics of domain causation a paradigm shift in empirical methods is necessary. How to apply fundamental mechanics to empirical methods and how to apply the codes of the predetermined variables of motion to results of past experiments such as CERN's LHC are presented. |
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