Physics Commons^™

Laser-Induced Breakdown Spectroscopy For Elemental Analysis In Bioarchaeology And Forensic Anthropology, Kelsi N. Kuehn

USF Tampa Graduate Theses and Dissertations

Within bioarchaeology and forensic anthropology, the current processes of differentiating between individual human skeletal remains are imprecise, costly, and inefficient. A novel analytical technique within anthropology, laser-induced breakdown spectroscopy (LIBS) can aid in the identification of human remains using rapid laser ablation occurring at the micro-scale, making the technique virtually non-destructive to the sample. Considering this, LIBS could offer a superior method for materials discrimination and human identification. This research sought to examine whether LIBS can be used to obtain elemental signatures within bones to distinguish individuals from one another in a rapid, non-destructive manner. Seven human skeletal donors and …

Truncations Of W (Infinity) Algebras, Mohammed Akram Fellah

Department of Physics Faculty Publications

We introduce a new class of Vertex Operator Algebras Y+ and their duals, which generalize the standard W-algebras WN of type sl(N). These algebras can be defined in terms of junctions of boundary conditions and interfaces in the GL-twisted N = 4 Super Yang Mills gauge theory.

The aim of these technical calculations is to find the relation of these ortho-symplectic Y-algebras to truncations of even W\infinity.

Microfluidic Study Of The Electrocoalescence Of Aqueous Droplets In Crude Oil, Thomas Leary, Mohsen Yeganeh, Charles Maldarelli

Publications and Research

In electrocoalescence, an electric field is applied to a dispersion of conducting water droplets in a poorly conducting oil to force the droplets to merge in the direction of the field. Electrocoalescence is used in petroleum refining to separate water from crude oil and in droplet-based microfluidics to combine droplets of water in oil and to break emulsions. Using a microfluidic design to generate a two-dimensional (2D) emulsion, we demonstrate that electrocoalescence in an opaque crude oil can be visualized with optical microscopy and studied on an individual droplet basis in a chamber whose height is small enough to make …

Coherent Virtual Absorption Of Light In Microring Resonators, Q. Zhong, L. Simonson, T. Kottos, Ramy El-Ganainy

Michigan Tech Publications

Light trapping and radiation process from linear reciprocal photonic resonators is one of the fundamental processes in optical science and engineering. Recently, the concept of coherent virtual absorption (CVA) of light was introduced and investigated for planar and cylindrical optical structures. The key feature of CVA is that by engineering the time dependence of the excitation waveform, one can temporarily store all the input energy in the optical structure without any leakage. Here we further explore this concept in integrated photonic setups made of microring resonators. By using coupled-mode theory, we derive an analytical expression for CVA in this platform. …

Gw190425: Observation Of A Compact Binary Coalescence With Total Mass ∼ 3.4 M⊙, B. P. Abbott, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Karla E. Ramirez, Satzhan Sitmukhambetov, Robert Stone, D. Tuyenbayev, Wenhui Wang, Adam Zadrozny

Physics and Astronomy Faculty Publications and Presentations

On 2019 April 25, the LIGO Livingston detector observed a compact binary coalescence with signal-to-noise ratio 12.9. The Virgo detector was also taking data that did not contribute to detection due to a low signal-to-noise ratio, but were used for subsequent parameter estimation. The 90% credible intervals for the component masses range from to (– if we restrict the dimensionless component spin magnitudes to be smaller than 0.05). These mass parameters are consistent with the individual binary components being neutron stars. However, both the source-frame chirp mass and the total mass of this system are significantly larger than those of …

On The Complexity Of Boson Sampling Using Atoms In Optical Lattices, Gopikrishnan Muraleedharan

Physics & Astronomy ETDs

The extended Church-Turing thesis says that any computation that can be done by a physically realizable model of computers can be efficiently computed by the simplest model of classical computer, a Turing machine. Since the introduction of the concept of quantum computers, a central goal has been to find instances where the extended Church- Turing thesis fails. In the current noisy intermediate-scale quantum devices era, one looks for such instances that can be simulated on modest devices of small scale in the presence of noise. In this thesis, we work with one such problem, namely the Boson Sampling problem. We …

The Crystal Structure Of (Cuxzn1-X)0:456in1:084ge0:46o3 (Cuzigo) Using Neutron And X-Ray Diffraction, Boluwatife A. Adekoya

College of Science and Health Theses and Dissertations

The solid solution (CuxZn(1-x))0.456In1.084Ge0.46O3 (CuZIGO) has a complex structure where zinc and copper partially occupy a site shared by indium and germanium. ZIGO, the x = 0 endpoint, is a potential transparent conducting oxide (TCO) with similar conductivity and transparency to cubic In2O3, which, when doped with Sn4+, is the most prevalent TCO. ZIGO structure possesses a tetragonal structure and has the ability to produce multiple new phases with an array of properties that are beneficial to identify and understand. Analyzing this structure is best done through chemical substitution to identify the newly produced phases. Copper is a suitable choice …

Experimental Investigation Of The Secondary And Backscatter Electron Emission From New Spacecraft Surface Materials, Millan F. Diaz-Aguado, John W. Bonnell, Stuart D. Bale, Justin Christensen, Phillip Lundgreen, Jordan Lee, Jr Dennison, Justin Dekany, Brian Wood, Mike Gruntman

Journal Articles

The emission of secondary and backscattered electrons influences spacecraft surface potentials and the surrounding plasma. Modern spacecraft use new materials for which secondary emission properties have been unavailable. In this work, the total electron yield (i.e., the sum of secondary and backscattered electron yields) was measured for niobium-C103 alloy, molybdenum Titanium, Zirconium, Molybdenum (TZM) alloy, tantalum-tungsten alloy, Elgiloy®, graphite lubricant (DAG 213®), and titanium nitride. The surface properties of tungsten were also measured for comparison with past test data. The materials were readied as spacecraft flight materials and temperature-treated ("annealed") to predicted peak flight temperatures. The yield properties for 10 …

Loops Versus Lines And The Compression Stiffening Of Cells, Mahesh C. Gandikota, Katarzyna Pogoda, Anne Van Oosten, Tyler A. Engstrom, Alison E. Patteson, Paul E. Janmey, J. M. Schwarz

Physics - All Scholarship

Both animal and plant tissue exhibit a nonlinear rheological phenomenon known as compression stiffening, or an increase in moduli with increasing uniaxial compressive strain. Does such a phenomenon exist in single cells, which are the building blocks of tissues? One expects an individual cell to compression soften since the semiflexible biopolymer-based cytoskeletal network maintains the mechanical integrity of the cell and in vitro semiflexible biopolymer networks typically compression soften. To the contrary, we find that mouse embryonic fibroblasts (mEFs) compression stiffen under uniaxial compression via atomic force microscopy studies. To understand this finding, we uncover several potential mechanisms for compression …

Reformulating Bell's Theorem: The Search For A Truly Local Quantum Theory, Mordecai Waegell, Kelvin J. Mcqueen

Philosophy Faculty Articles and Research

The apparent nonlocality of quantum theory has been a persistent concern. Einstein et al. (1935) and Bell (1964) emphasized the apparent nonlocality arising from entanglement correlations. While some interpretations embrace this nonlocality, modern variations of the Everett-inspired many worlds interpretation try to circumvent it. In this paper, we review Bell's “no-go” theorem and explain how it rests on three axioms, local causality, no superdeterminism, and one world. Although Bell is often taken to have shown that local causality is ruled out by the experimentally confirmed entanglement correlations, we make clear that it is the conjunction of the …

Loop-Closure Kinetics Reveal A Stable, Right-Handed Dna Intermediate In Cre Recombination, Massa J. Shoura, Stefan M. Giovan, Alexandre A. Vetcher, Riccardo Ziraldo, Andreas Hanke, Stephen D. Levene

Physics and Astronomy Faculty Publications and Presentations

In Cre site-specific recombination, the synaptic intermediate is a recombinase homotetramer containing a pair of loxP DNA target sites. The enzyme system's strand-exchange mechanism proceeds via a Holliday-junction (HJ) intermediate; however, the geometry of DNA segments in the synapse has remained highly controversial. In particular, all crystallographic structures are consistent with an achiral, planar Holliday-junction (HJ) structure, whereas topological assays based on Cre-mediated knotting of plasmid DNAs are consistent with a right-handed chiral junction. We use the kinetics of loop closure involving closely spaced (131–151 bp) loxP sites to investigate the in-aqueo ensemble of conformations for the longest-lived looped DNA …

Perturbed Field Ionization For Improved State Selectivity, Vincent C. Gregoric, Jason Bennett, Bianca R. Gualtieri, Hannah P. Hastings, Ankitha Kannad, Zhimin Cheryl Liu, Maia R. Rabinowitz, Zoe A. Rowley, Maio Wang, Lauren Yoast, Thomas J. Carroll, Michael W. Noel

Physics and Astronomy Faculty Publications

Selective field ionization (SFI) is used to determine the state or distribution of states to which a Rydberg atom is excited. By evolving a small perturbation to the ramped electric field using a genetic algorithm, the shape of the time-resolved ionization signal can be controlled. This allows for the separation of signals from pairs of states that would be indistinguishable with unperturbed SFI. Measurements and calculations are presented that demonstrate this technique and shed light on how the perturbation directs the pathway of the electron to ionization. Pseudocode for the genetic algorithm is provided. Using the improved resolution afforded by …

Nuclear-Modification Factor Of Charged Hadrons At Forward And Backward Rapidity In P + Al And P + Au Collisions At √Snn=200gev, Mike Daugherity, Donald Isenhower, Rusty Towell

Engineering and Physics

The PHENIX experiment has studied nuclear effects in p+Al and p+Au collisions at √sNN=200GeV on charged hadron production at forward rapidity (1.4<η<2.4, p-going direction) and backward rapidity (−2.2<η<−1.2, A-going direction). Such effects are quantified by measuring nuclear modification factors as a function of transverse momentum and pseudorapidity in various collision multiplicity selections. In central p+Al and p+Au collisions, a suppression (enhancement) is observed at forward (backward) rapidity compared to the binary scaled yields in p+p collisions. The magnitude of enhancement at backward rapidity is larger in p+Au collisions than in p+Al collisions, which have a smaller number of participating nucleons. However, the results at forward rapidity show a similar suppression within uncertainties. The results in the integrated centrality are compared with calculations using nuclear parton distribution functions, which show a reasonable agreement at the forward rapidity but fail to describe the backward rapidity enhancement.

Oscillating Scalar Fields And The Hubble Tension: A Resolution With Novel Signatures, Tristan L. Smith, V. Poulin, M. A. Amin

Physics & Astronomy Faculty Works

We present a detailed investigation of a subdominant oscillating scalar field [“early dark energy” (EDE)] in the context of resolving the Hubble tension. Consistent with earlier work, but without relying on fluid approximations, we find that a scalar field frozen due to Hubble friction until log10(zc)∼3.5, reaching ρEDE(zc)/ρtot∼10% and diluting faster than matter afterwards, can bring cosmic microwave background (CMB), baryonic acoustic oscillations, supernovae luminosity distances, and the late-time estimate of the Hubble constant from the SH0ES Collaboration into agreement. A scalar field potential that scales as V(ϕ)∝ϕ2n with 2≲n≲3.4 around the minimum is preferred at the 68% confidence level, …

J/Ψ And Ψ(2s) Production At Forward Rapidity In P+P Collisions At √S=510  Gev, Mike Daugherity, Donald Isenhower, Rusty Towell

Engineering and Physics

The PHENIX experiment at the Relativistic Heavy Ion Collider has measured the differential cross section, mean transverse momentum, mean transverse momentum squared of inclusive J/ψ, and cross section ratio of ψ(2S) to J/ψ at forward rapidity in p+p collisions at √s=510  GeV via the dimuon decay channel. Comparison is made to inclusive J/ψ cross sections measured at √s=200  GeV and 2.76–13 TeV. The result is also compared to leading-order nonrelativistic QCD calculations coupled to a color-glass-condensate description of the low-x gluons in the proton at low transverse momentum (pT) and to next-to-leading order nonrelativistic QCD calculations for the rest of …

The Emergence Of The Local Moment Molecular Spin Transistor, Guanhua Hao, Ruihua Cheng, Peter Dowben

Peter Dowben Publications

Local moment molecular systems have now been used as the conduction channel in gated spintronics devices, and some of these three terminal devices might even be considered molecular spin transistors. In these systems, the gate voltage can be used to tune the molecular level alignment, while applied magnetic fields have an influence on the spin state, altering the magnetic properties, and providing insights to the magnetic anisotropy. More recently, the use of molecular spin crossover complexes, as the conduction channel, has led to devices that are both nonvolatile and have functionality at higher temperatures. Indeed, some devices have now been …

Syllabus Ee330 Electromagnetics, Nicholas Madamopoulos

Open Educational Resources

Concepts covered in the undergraduate electrical engineering class of electromagnetics

Characterization Of A Trochoidal Electron Monochromator, Jesse Kruse

Honors Theses

This thesis presents a quantitative study of a trochoidal electron monochromator and attempts to observe the 2p^53p^2 resonance in neon. A detailed description of the experimental apparatus, including the electron beam system, the vacuum system, and the light analysis system, is presented first. Then, we discuss the theory of how the electron beam is monochromatized, how we measured monochomatization, and how we analyze the light being emitted from the collision cell. The light analysis system is capable of accurately measuring the relative Stokes parameters for any polarization of light, and the electron beam system is capable of producing electron beams …

Strain-Driven Disproportionation At A Correlated Oxide Metal-Insulator Transition, T. H. Kim, Tula R. Paudel, R. J. Green, K. Song, H.-S. Lee, S.-Y. Choi, J. Irwin, B. Noesges, L. J. Brillson, M. S. Rzchowski, G. A. Sawatzky, Evgeny Y. Tsymbal, C. B. Eom

Department of Physics and Astronomy: Faculty Publications

Metal-to-insulator phase transitions in complex oxide thin films are exciting phenomena which may be useful for device applications, but in many cases the physical mechanism responsible for the transition is not fully understood. Here we demonstrate that epitaxial strain generates local disproportionation of the NiO₆ octahedra, driven through changes in the oxygen stoichiometry, and that this directly modifies the metal-to-insulator phase transition in epitaxial (001) NdNiO₃ thin films. Theoretically, we predict that the Ni-O-Ni bond angle decreases, while octahedral tilt and local disproportionation of the NiO₆ octahedra increases resulting in a small band gap in an otherwise …

High Dielectric Ternary Oxides From Crystal Structure Prediction And High-Throughput Screening, Jingyu Qu, David Zagaceta, Weiwei Zhang, Qiang Zhu

Physics & Astronomy Faculty Research

The development of new high dielectric materials is essential for advancement in modern electronics. Oxides are generally regarded as the most promising class of high dielectric materials for industrial applications as they possess both high dielectric constants and large band gaps. Most previous researches on high dielectrics were limited to already known materials. In this study, we conducted an extensive search for high dielectrics over a set of ternary oxides by combining crystal structure prediction and density functional perturbation theory calculations. From this search, we adopted multiple stage screening to identify 441 new low-energy high dielectric materials. Among these materials, …