Ultra-High Carrier Mobilities In Ferroelectric Domain Wall Corbino Cones At Room Temperature, 2022 Queen’s University Belfast
Ultra-High Carrier Mobilities In Ferroelectric Domain Wall Corbino Cones At Room Temperature, Conor J. Mccluskey, Matthew G. Colbear, James P.V. Mcconville, Shane J. Mccartan, Jesi R. Maguire, Michele Conroy, Kalani Moore, Alan Harvey, Felix Trier, Ursel Bangert, Alexei Gruverman, Manuel Bibes, Amit Kumar, Raymong G.P. Mcquaid, J. Marty Gregg
Alexei Gruverman Publications
Recently, electrically conducting heterointerfaces between dissimilar band-insulators (such as lanthanum aluminate and strontium titanate) have attracted considerable research interest. Charge transport has been thoroughly explored and fundamental aspects of conduction firmly established. Perhaps surprisingly, similar insights into conceptually much simpler conducting homointerfaces, such as the domain walls that separate regions of different orientations of electrical polarisation within the same ferroelectric band-insulator, are not nearly so well-developed. Addressing this disparity, we herein report magnetoresistance in approximately conical 180° charged domain walls, which occur in partially switched ferroelectric thin film single crystal lithium niobate. This system is ideal for such measurements: firstly, …
Applications Of Machine Learning Algorithms In Materials Science And Bioinformatics, 2022 University of New Mexico
Applications Of Machine Learning Algorithms In Materials Science And Bioinformatics, Mohammed Quazi
Mathematics & Statistics ETDs
The piezoelectric response has been a measure of interest in density functional theory (DFT) for micro-electromechanical systems (MEMS) since the inception of MEMS technology. Piezoelectric-based MEMS devices find wide applications in automobiles, mobile phones, healthcare devices, and silicon chips for computers, to name a few. Piezoelectric properties of doped aluminum nitride (AlN) have been under investigation in materials science for piezoelectric thin films because of its wide range of device applicability. In this research using rigorous DFT calculations, high throughput ab-initio simulations for 23 AlN alloys are generated.
This research is the first to report strong enhancements of piezoelectric properties …
Developing A Data Acquisition System For Use In Cold Neutral Atom Traps, 2022 California Polytechnic State University, San Luis Obispo
Developing A Data Acquisition System For Use In Cold Neutral Atom Traps, Jonathan E. Fuzaro Alencar
Physics
The rising interest in quantum computing has led to new quantum systems being developed and researched. Among these are trapped neutral atoms which have several desirable features and may be configured and operated on using lasers in an optical lattice. This work describes the development of a new data acquisition system for use in tuning lasers near the precise hyperfine transition frequencies of Rb 87 atoms, a crucial step in the functionality of a neutral atom trap. This improves on previous implementations that were deprecated and limited in laser frequency sweep range. Integration into the experiment was accomplished using an …
Symmetries, Zero Modes And Light Transport In Non-Hermitian Photonics, 2022 The Graduate Center, City University of New York
Symmetries, Zero Modes And Light Transport In Non-Hermitian Photonics, Jose David Hernandez Rivero
Dissertations, Theses, and Capstone Projects
We approach some fundamental aspects of photonic dissipative systems treated by a non-Hermitian theory. Inspired by the possibilities provided by some major non-Hermitian symmetries, we study systematically the properties of the novel pseudochirality, pseudo-anti-Hermiticity, and supersymmetry. We analyze other aspect of photonics, the zero mode, which has a profound connection to non-Hermitian physics. We propose a scheme to realize a zero mode that exists even in the absence of symmetries. Finally, we approach light transport in non-Hermitian photonic systems, where the introduction of gain and loss can modify drastically the propagation speed of wavepackets.
External Beam Alignment System For Quantitative Proton Induced Gamma-Ray Emission (Pige) Spectroscopy, 2022 Union College - Schenectady, NY
External Beam Alignment System For Quantitative Proton Induced Gamma-Ray Emission (Pige) Spectroscopy, Elias Ottens
Honors Theses
The effects of pollution on the ecosystem are paramount in our society, permeating air, soil, and drinking water. One contaminant of concern is per- and polyfluoroalkyl substances (PFAS), also referred to as "forever chemicals", which contains fluorine (F), a potentially harmful element to humans. To investigate pollution in the environment, it is necessary to make accurate measurements of the distribution and concentrations of these PFAS chemicals. To do this, soil samples are collected and analyzed using Particle Induced Gamma-ray Emission (PIGE) via the Union College Ion Beam Analysis Laboratory's (UCIBAL) particle accelerator. A 2.2 MeV proton beam comes into contact …
Feasibility Of Obtaining Surface Layer Moisture Flux Using An Ir Thermometer, 2022 Air Force Institute of Technology
Feasibility Of Obtaining Surface Layer Moisture Flux Using An Ir Thermometer, Steven T. Fiorino, Lance Todorowski, Jaclyn Schmidt, Yogendra Raut, Jacob Margraf
Faculty Publications
This paper evaluates the feasibility of a method using a single hand-held infrared (IR) thermometer and a mini tower of wet and dry paper towels to psychometrically obtain surface layer temperature and moisture gradients and fluxes. Sling Psychrometers have long been standard measuring devices for quantifying the thermodynamics of near-surface atmospheric gas–vapor mixtures, specifically moisture parameters. However, these devices are generally only used to measure temperature and humidity at one near-surface level. Multiple self-aspirating psychrometers can be used in a vertical configuration to measure temperature and moisture gradients and fluxes in the first 1–2 m of the surface layer. This …
Contributions Of Vibrational Spectroscopy To Virology: A Review, 2022 Technological University Dublin
Contributions Of Vibrational Spectroscopy To Virology: A Review, Iqra Chaudhary, Naomi Jackson, Denise Denning, Luke O'Neill, Hugh Byrne
Articles
Vibrational spectroscopic techniques, both infrared absorption and Raman scattering, are high precision, label free analytical techniques which have found applications in fields as diverse as analytical chemistry, pharmacology, forensics and archeometrics and, in recent times, have attracted increasing attention for biomedical applications. As analytical techniques, they have been applied to the characterisation of viruses as early as the 1970s, and, in the context of the coronavirus disease 2019 (COVID-19) pandemic, have been explored in response to the World Health Organisation as novel methodologies to aid in the global efforts to implement and improve rapid screening of viral infection. This review …
Nonequilibrium And Nonlinear Dynamics In Collective Spin Models And Implementations Using Quantum Feedback Control, 2022 University of New Mexico
Nonequilibrium And Nonlinear Dynamics In Collective Spin Models And Implementations Using Quantum Feedback Control, Manuel H. Munoz Arias
Physics & Astronomy ETDs
Out-of-equilibrium dynamics generalizes the study of ground states of quantum Hamiltonians at zero temperature, to that of dynamical quasi-steady states of quantum systems far from equilibrium. In this dissertation I discuss dynamical quantum phase transitions and out-of-equilibrium phases of matter in models of collective spins with multi-body interactions. These models, based on collective degrees of freedom, allow an exact description of the thermodynamic limit via the mean-field description. In this limit, the nonequilibrium dynamics of properties of quantum states is mapped to the nonlinear dynamics of classical variables, and thus it can be analyzed using tools from the theory of …
Circulation Transfer Between Adjacent Target Bose-Einstein Condensates, 2022 Georgia Southern University
Circulation Transfer Between Adjacent Target Bose-Einstein Condensates, Charles B. Henry
Honors College Theses
We propose an atomtronic rotation sensor design that consists of an array of Bose-Einstein Condensates (BECs) that are confined in a double-target-array potential. The rotation sensor's purpose is to measure the speed of the rotating frame, with respect to the “fixed stars", the sensor rests in. The atomtronic system is an ultracold gas of sodium atoms that have been compressed by laser light into a thin quasi-2D horizontal plane and further confined in the horizontal plane by a double-target-array potential. A target BEC is a combination of disk BEC that is surrounded by a ring BEC. A double-target BEC is …
Lifetime Measurement Of The Xi_C^+ Using Belle Ii Monte Carlo, 2022 University of Mississippi
Lifetime Measurement Of The Xi_C^+ Using Belle Ii Monte Carlo, Paul Gebeline
Honors Theses
This analysis uses simulated data from the Belle II experiment to measure the lifetime of the Xi_c^+ baryon. Three different decay modes are investigated to explore the feasibility and accuracy of such measurements at Belle II. The Xi_c^+ lifetime is measured using one of these modes after reducing backgrounds from sources other than the decay of interest. The final result is 464 +/- 15 fs, which is consistent with the expected result of 442 fs within uncertainty. This result shows that Belle II can make competitive measurements of particle properties and decays.
Structural And Spectroscopic Analysis For Silver Bulk And Nanoparticles, 2022 Department of Applied Science, University of Technology, Baghdad, Iraq.
Structural And Spectroscopic Analysis For Silver Bulk And Nanoparticles, Hajir M. Fadhil, Khaleel I. Hassoon, Hyder A. Salih
Karbala International Journal of Modern Science
In this research work, a pulsed Nd-YْAG laser having a wavelength of 1064 nm and energy (400-700 mJ (has been utilized as a source in an induced breakdown spectroscopy (LIBS) experiment to determine the density of electron and the tem-perature of Ag-plasma. Two forms of silver (as a bulk and as a compressed nano powder) have been used as targets in the LIBSs setup. The aim of the present work is to study the impact of target properties and laser energy on the plasma fea-tures formed by the interaction between a pulsed laser and these two forms of silver. The …
Stabilization Of Phenanthrene Anions In Helium Nanodroplets, 2022 University of Innsbruck
Stabilization Of Phenanthrene Anions In Helium Nanodroplets, Siegfried Kollotzek, Farhad Izadi, Miriam Meyer, Stefan Bergmeister, Fabio Zappa, Stephan Denifl, Olof E. Echt, Paul Scheier, Elisabeth Gruber
Faculty Publications
It has been debated for years if the polycyclic aromatic hydrocarbon phenanthrene exists in its anionic form, or, in other words, if its electron affinity (EA) is positive or negative. In this contribution we confirm that the bare phenanthrene anion Ph- created in a binary collision with an electron at room temperature has a lifetime shorter than microseconds. However, the embedding of neutral phenanthrene molecules in negatively charged helium nanodroplets enables the formation of phenanthrene anions by charge transfer processes and the stabilization of the latter in the ultracold environment. Gentle shrinking of the helium matrix of phenanthrene-doped HNDs …
Automation Of The Transition Identification Procedure For Trapping Rubidium Atoms In A Magneto-Optical Trap, 2022 California Polytechnic State University, San Luis Obispo
Automation Of The Transition Identification Procedure For Trapping Rubidium Atoms In A Magneto-Optical Trap, Michael P. Fletcher
Physics
The words “quantum computer” often conjure images of science fiction and unrealistic technology from an impossible future. Some may even believe that they aren’t real or are only theoretical. The truth is that quantum computers are real, tangible systems with real life uses and rooted in credible scientific research. Today, many groups of scientists collaborate on research into better ways of implementing and improving quantum computing techniques. This paper will be addressing the systems required and phenomena used to achieve neutral atom trapping for quantum computation. This thesis will outline the physical phenomena involved with the frequency tuning process for …
Porous Silicon Photonics For Label-Free Interferometric Biosensing And Flat Optics, 2022 Clemson University
Porous Silicon Photonics For Label-Free Interferometric Biosensing And Flat Optics, Tahmid Hassan Talukdar
All Dissertations
This dissertation uses porous silicon as a material platform to explore novel optical effects in three domains: (i) It studies dispersion engineering in integrated waveguides to achieve high performance group index sensing. With proper design parameters, the sensor waveguides can theoretically achieve 6 times larger group index shift compared to the actual bulk effective refractive index shift. We demonstrate the guided mode confinement factor to be a key parameter in design and implementation of these waveguides. (ii) It explores multicolor laser illumination to experimentally demonstrate perceptually enhanced colorimetric sensing, overcoming the limitations faced by many contemporary colorimetric sensors. Our technique …
Development Of A Vector Magnetometer Based On Electromagnetically Induced Transparency In 87rb Atomic Vapor, 2022 William & Mary
Development Of A Vector Magnetometer Based On Electromagnetically Induced Transparency In 87rb Atomic Vapor, Alexander Toyryla
Undergraduate Honors Theses
We present progress towards the development of an atomic magnetometer capable of accurate scalar and vector magnetic field measurements with high sensitivity and no need for external calibration. The proposed device will use the interaction between a bi-chromatic laser field and rubidium vapor to derive magnetic field magnitude and direction from measured amplitudes of Electromagnetically Induced Transparency (EIT) resonances. Since the proposed method requires precision control of light polarization, we observe the performance capabilities of a liquid crystal device to dynamically rotate the polarization of the laser field. Another goal in this project is to establish a polarization locking mechanism …
Alkali Linewidths Under High Temperatures And Pressures Of 3he, 2022 William & Mary
Alkali Linewidths Under High Temperatures And Pressures Of 3he, Michael Parker
Undergraduate Honors Theses
Current research at Thomas Jefferson National Accelerator Facility is being conducted to study the spin structure of the neutron through collisions with polarized 3He nuclei. The helium is contained in high pressure glass vessels (called cells) along with nitrogen, rubidium, and potassium. To deduce the spin structure from collisions, we need to know the precise number density of 3He in the cell. The process of polarizing 3He through spin-exchange optical pumping requires nitrogen and alkali metal. We can use the absorption linewidths of rubidium and potassium to more accurately determine the density of helium. Throughout my research, I collected absorption …
Co-Planar Waveguides For Microwave Atom Chips, 2022 William & Mary
Co-Planar Waveguides For Microwave Atom Chips, Morgan Logsdon
Undergraduate Honors Theses
This thesis describes research to develop co-planar waveguides (CPW) for coupling microwaves from mm-scale coaxial cables into 50 μm-scale microstrip transmission lines of a microwave atom chip. This new atom chip confines and manipulates atoms using spin-specific microwave AC Zeeman potentials and is particularly well suited for trapped atom interferometry. The coaxial-to-microstrip coupler scheme uses a focused CPW (FCPW) that shrinks the microwave field mode while maintaining a constant 50 Ω impedance for optimal power coupling. The FCPW development includes the simulation, design, fabrication, and testing of multiple CPW and microstrip prototypes using aluminum nitride substrates. Notably, the FCPW approach …
An Atomic Magnetometer Based On Nonlinear Magneto-Optical Polarization Rotation, 2022 William & Mary
An Atomic Magnetometer Based On Nonlinear Magneto-Optical Polarization Rotation, Jiahui Li
Undergraduate Honors Theses
Magnetometers with high precision and accuracy have wide applications across various areas. We are developing an atomic magnetometer based on nonlinear magneto-optical rotation (NMOR). The magnetometer measures the polarization rotation of a light field, which is proportional to the magnetic field strength. However, such a magnetometer usually has a limited operation range and stops working for fields stronger than the Earth's magnetic field. To overcome this shortage, we implement frequency and amplitude modulation that induces side frequencies in the Fourier space which allows us to measure strong magnetic fields, up to 200 mG. We have achieved 60 pT sensitivity for …
Design, Fabrication, And Characterization Of An Array Of Graphene Based Variable Capacitors, 2022 University of Arkansas, Fayetteville
Design, Fabrication, And Characterization Of An Array Of Graphene Based Variable Capacitors, Millicent Nkirote Gikunda
Graduate Theses and Dissertations
Since it was first isolated and characterized in 2004, graphene has shown the potential for a technological revolution. This is due to its amazing physical properties such as high electrical conductivity, high thermal conductivity, and extreme flexibility. Freestanding graphene membranes naturally possesses an intrinsic rippled structure, and these ripples are in constant random motion even room temperatures. Occasionally, the ripples undergo spontaneous buckling (change of curvature from concave to convex and vice versa) and the potential energy associated with this is a double well potential. This movement of graphene is a potential source of vibrational energy.
In this dissertation, we …
Experimental Investigation Of All-Optical Production Of Metastable Krypton, 2022 Old Dominion University
Experimental Investigation Of All-Optical Production Of Metastable Krypton, Joshua Carl Frechem
Physics Theses & Dissertations
Metastable production of noble gases requires significant energy due to their filled valence shells. These transitions from the ground state are in the vacuum ultraviolet and extreme ultraviolet, which are relatively inaccessible to lasers. This necessitates the use of either electron/ion bombardment via inefficient glow discharges or the use of high-power lasers and nonlinear processes. The all-optical production efficiency using these high-power lasers promises to be orders of magnitude higher than glow discharges, but far more costly. This work looks to improve all-optical production of metastable krypton (Kr*) through the use of a commercially available vacuum ultraviolet lamp with a …