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Specific Heat, Magnetic Susceptibility, And The Effect Of Pressure On Structural Properties And Valence Of Eumn2si2, Euco2si2, And Eu5in2sb6, Brian Edward Light

UNLV Theses, Dissertations, Professional Papers, and Capstones

Many intermetallic solids containing elements from the rare earth series show interesting and unusual behavior associated with 4f electrons. This behavior includes unusual magnetic order, strongly correlated electrons, intermediate valence, heavy fermions, the Kondo effect, superconductivity, and non-Fermi liquid (NFL) to name a few. When long range magnetic order is suppressed to T = 0 K by the application of an external tuning parameter such as pressure, magnetic field, or chemical doping, a quantum critical point (QCP) appears in which strong quantum fluctuations give rise to many of the mentioned unusual properties.

Most of the past studies on unusual 4f …

A Study On Radiative Pion Capture As A Source Of Background In The Search For Muon To Electron Conversion At The Mu2e Experiment., Joseph Leibson

Electronic Theses and Dissertations

The following thesis will cover the process of radiative pion capture in the Mu2e experiment at Fermi National Accelerator Laboratory. Radiative pion capture (RPC) is a process that is able to mimic the signal of an electron spawned from the neutrino-less conversion of a muon. In this paper we will discuss the current Standard Model accepted by physicists, and discuss charged lepton flavor violation, which is the motivation behind Mu2e. This paper will cover the theory behind Mu2e and RPC, as well as the apparatus involved in the Mu2e experiment. Next, software and simulations used to carry out the RPC …

Large-Scale Atomistic Simulations Of Complex And Functional Properties Of Ferroic Materials, Raymond Thomas Walter

Graduate Theses and Dissertations

Ferroelectric (FE) nanostructures have attracted considerable attention as our abilities improve to synthesize them and to predict their properties by theoretical means. Depolarizing field effects at interfaces of FE heterostructures are particularly notable for causing topological defects such as FE vortices and negative dielectric responses in superlattices. In this thesis, I employ two large-scale atomistic techniques, the first-principles-based effective Hamiltonian (HEff) method and the linear-scaling three-dimensional fragment (LS3DF) method. I use these methods to explore optical rotation in FE vortices, electro-optic effects in FE vortices and skyrmions, and voltage amplification via negative capacitance in ferroelectric-paraelectric superlattices. We employ HEff in …

Feedforward And Feedback Signals In The Olfactory System, Srimoy Chakraborty

Graduate Theses and Dissertations

The conglomeration of myriad activities in neural systems often results in prominent oscillations. The primary goal of the research presented in this thesis was to study effects of sensory stimulus on the olfactory system of rats, focusing on the olfactory bulb (OB) and the anterior piriform cortex (aPC). Extracellular electrophysiological measurements revealed distinct frequency bands of oscillations in OB and aPC. However, how these oscillatory fluctuations help the animal to process sensory input is not clearly understood. Here we show high frequency oscillations in olfactory bulb carry feedforward signals to anterior piriform cortex whereas feedback from the aPC is predominantly …

Generation And Use Of Femtosecond, Gigawatt, Near Infrared Laser Pulses From An Amplified, Mode-Locked, Ti:Sapphire Laser, David Anthony Valdés

Optical Science and Engineering ETDs

This work modeled the early to middle successes achieved in the field of ultrafast, high peak power optics, beginning with the work of Nobel Prize winners Donna Strickland and Gérard Mourou in 1985. In our work, 100 fs light pulses of around 800 nm were generated by a Ti:Sapphire oscillator, then amplified to approximately 30 GW peak power using a chirped pulse amplification system that included regenerative and multi-pass amplifiers. As a verification of our pulses having high peak powers and ultrashort durations, they were then used to strike water, glass, and a Kerr Cell. Supercontinuum generation was observed as …

Topological Insulating States In Photonics And Acoustics, Xiang Ni

Dissertations, Theses, and Capstone Projects

Recent surge of interest in topological insulators, insulating in their interior but conducting at the surfaces or interfaces of different domains, has led to the discovery of a variety of new topological states, and their topological invariants are characterized by numerous approaches in the category of topological band theory. The common features shared by topological insulators include, the topological phase transition occurs if the bulk bandgap is formed due to the symmetries reduction, the topological invariants exist characterizing the global properties of the material and inherently robust to disorder and continuous perturbations irrespective of the local details. Most importantly, these …

The International Community Coordinated Modeling Center Space Weather Modeling Capabilities Assessment: Overview Of Ionosphere/Thermosphere Activities, Ludger Scherliess, I. Tsagouri, E. Yizengaw, S. Bruinsma, J. S. Shim, A. Coster, J. M. Retterer

All Physics Faculty Publications

The Earth's ionosphere/thermosphere (I/T) system exhibits complicated weather variability that can have adverse effects on human operations and systems, and consequently, there is a need for both accurate and reliable specifications and forecasts for this region. As part of the international effort to evaluate and assess the predictive capabilities of space weather models, four working groups for the I/T system have been created with the goal to devise a concerted model validation effort for the I/T environment. This paper presents an overview of the team efforts and reports on the progress made. As a first step, the working teams have …

Terahertz Absorption Spectra Of Silicate Cosmic Analog Dusts Using A Novel Spectrometer, Binh Phan

Honors Projects

Metal-containing amorphous silicate grains are expected to be a major component of interstellar dust. Amorphous silicate grains containing magnesium, iron, and calcium have been synthesized in the IWU chemistry department. I have contributed to the construction and testing of an instrument that will be used to measure terahertz absorption spectra of cold samples at astronomically interesting temperatures.

To study cosmic dust analogs, we installed dust samples, embedded in low-density polyethylene (LDPE) pellets, in a sample-exchanger and cooled it down within a cryostat to 3.0 Kelvin. Using a blackbody radiation source, we measured the transmission of terahertz light through those samples …

High Resolution Near-Infrared/Visible Intracavity Laser Spectroscopy Of Small Molecules, Jack Harms

Dissertations

Intracavity laser spectroscopy has been used to study the electronic structure of several small molecules. The molecules studied as part of this dissertation include germanium hydride (GeH), copper oxide (CuO), nickel chloride (NiCl), platinum fluoride (PtF), platinum chloride (PtCl), and copper hydroxide (CuOH). This work encompasses five peer-reviewed publications and two submitted manuscripts.

Search For W Boson Decays To Three Charged Pions, A. M. Sirunyan

Department of Physics and Astronomy: Faculty Publications

For the first time, a search for the rare decay of the W boson to three charged pions has been performed. Proton-proton collision data recorded by the CMS experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 77.3 fb⁻¹, have been analyzed. No significant excess is observed above the background expectation. An upper limit of 1.01 × 10⁻⁶ is set at 95% confidence level on the branching fraction of the W boson to three charged pions. This provides a strong motivation for theoretical calculations of this branching fraction.

Porting Symbolic Libraries From Maple To Python, James Lewis

Physics Capstone Projects

Utah State University has a database of tables of the known solutions of the Einstein Field Equation. This database is primarily recorded in the symbolic computing program Maple. This database needs to be translated into Python code so the information can be more accessible to the general public. This translation was successful for one table, which means that it is possible to translate the entire database.

Jet Shapes Of Isolated Photon-Tagged Jets In Pb-Pb And Pp Collisions At √SNn=5.02 Tev, A. M. Sirunyan

Department of Physics and Astronomy: Faculty Publications

The modification of jet shapes in Pb-Pb collisions, relative to those in pp collisions, is studied for jets associated with an isolated photon. The data were collected with the CMS detector at the LHC at a nucleon-nucleon center-of-mass energy of 5.02 TeV. Jet shapes are constructed from charged particles with track transverse momenta (p_T ) above 1 GeV/c in annuli around the axes of jets with p^jet_T > 30 GeV/c associated with an isolated photon with p^γ_T > 60 GeV/c. The jet shape distributions are consistent between peripheral Pb-Pb and pp collisions, …

Frequency Modulated Hybrid Photonic Crystal Laser By Thermal Tuning, Sharon M. Butler, Andrei P. Bakoz, Praveen K.J. Singaravelu, A. A. Liles, Ben O’Shaughnessy, E. A. Viktorov, Liam O'Faolain, Stephen P. Hegarty

Cappa Publications

We demonstrate frequency modulation (FM) in an external cavity (EC) III-V/silicon laser, comprising a reflective semiconductor optical amplifier (RSOA) and a silicon nitride (SiN) waveguide vertically coupled to a 2D silicon photonic crystal (PhC) cavity. The PhC cavity acts as a tunable narrowband reflector giving wavelength selectivity. The FM was achieved by thermo-optical modulation of the reflector via a p-n junction. Single-mode operation was ensured by the short cavity length, overlapping only one longitudinal laser mode with the reflector. We investigate the effect of reflector modulation theoretically and experimentally and predict a substantial tracking of the resonator by the laser …

Realization Of Tensor Product And Of Tensor Factorization Of Rational Functions, Daniel Alpay, Izchak Lewkowicz

Mathematics, Physics, and Computer Science Faculty Articles and Research

We study the state space realization of a tensor product of a pair of rational functions. At the expense of “inflating” the dimensions, we recover the classical expressions for realization of a regular product of rational functions. Under an additional assumption that the limit at infinity of a given rational function exists and is equal to identity, we introduce an explicit formula for a tensor factorization of this function.

Autonomous Watercraft Simulation And Programming, Nicholas J. Savino

Student Scholar Showcase

Automation of various modes of transportation is thought to make travel more safe and efficient. Over the past several decades, advances to semi-autonomous and autonomous vehicles have led to advanced autopilot systems on planes and boats, and an increasing popularity of self-driving cars. We predicted the motion of an autonomous vehicle using simulations in Python. The simulation models the motion of a small scale watercraft, which can then be built and programmed using an Arduino Microcontroller. We examined different control methods for a simulated rescue craft to reach a target. We also examined the effects of different factors, such as …

Measurements Of Μμ Pairs From Open Heavy Flavor And Drell-Yan In P + P Collisions At Ffiffi S P = 200 Gev, Mike Daugherity, Donald Isenhower, Rusty Towell

Engineering and Physics

PHENIX reports differential cross sections of μμ pairs from semileptonic heavy-flavor decays and the Drell-Yan production mechanism measured in p+p collisions at √s=200  GeV at forward and backward rapidity (1.2<|η|<2.2). The μμ pairs from c¯c, b¯b, and Drell-Yan are separated using a template fit to unlike- and like-sign muon pair spectra in mass and pT. The azimuthal opening angle correlation between the muons from c¯c and b¯b decays and the pair-pT distributions are compared to distributions generated using pythia and powheg models, which both include next-to-leading order processes. The measured distributions for pairs from c¯c are consistent with pythia calculations. The c¯c data present narrower azimuthal correlations and softer pT distributions compared to distributions generated from powheg. The b¯b data are well described by both models. The extrapolated total cross section for bottom production is 3.75±0.24(stat)±0.350.50(syst)±0.45(global)  [μb], which is consistent with previous measurements at the Relativistic Heavy Ion Collider in the same system at the same collision energy and is approximately a factor of 2 higher than the central value calculated with theoretical models. The measured Drell-Yan cross section is in good agreement with next-to-leading-order quantum-chromodynamics calculations.

Testing Quantum Coherence In Stochastic Electrodynamics With Squeezed Schrödinger Cat States, Wayne Cheng-Wei Huang, Herman Batelaan

Department of Physics and Astronomy: Faculty Publications

The interference pattern in electron double-slit diffraction is a hallmark of quantum mechanics. A long-standing question for stochastic electrodynamics (SED) is whether or not it is capable of reproducing such effects, as interference is a manifestation of quantum coherence. In this study, we used excited harmonic oscillators to directly test this quantum feature in SED. We used two counter-propagating dichromatic laser pulses to promote a ground-state harmonic oscillator to a squeezed Schrödinger cat state. Upon recombination of the two well-separated wavepackets, an interference pattern emerges in the quantum probability distribution but is absent in the SED probability distribution. We thus …

Water And Salt At The Lipid-Solvent Interface, James M. Kruczek

USF Tampa Graduate Theses and Dissertations

Lipid bilayers are important biological structures. The changes in bilayer properties are induced by the composition of the bilayer as well as the solvent. In this work, we study the effects of different molecular makeups of lipids and ionic solvents with molecular dynamics simulations to determine their effect on the bilayer interface. In particular, we look at how different carbon chain bindings affect water viscosity at the interface and allow for a less permeable bilayer. Additionally, we examine the changes to the bilayer due to the presence of the most biologically relevant salt ions. Lastly, we show how the pharmacological …

Observation Of Single Top Quark Production In Association With A Z Boson In Proton-Proton Collisions At √S = 13 Tev, A. M. Sirunyan

Department of Physics and Astronomy: Faculty Publications

The observation of single top quark production in association with a Z boson and a quark (tZq) is reported. Events from proton-proton collisions at a center-of-mass energy of 13 TeV containing three charged leptons (either electrons or muons) and at least two jets are analyzed. The data were collected with the CMS detector in 2016 and 2017 and correspond to an integrated luminosity of 77.4fb⁻¹. The increased integrated luminosity, a multivariate lepton identification, and a redesigned analysis strategy improve significantly the sensitivity of the analysis compared to previous searches for tZq production. The tZq signal is …

Observation Of Two Excited B+C States And Measurement Of The B+C (2s) Mass In Pp Collisions At √S = 13 Tev, A. M. Sirunyan

Department of Physics and Astronomy: Faculty Publications

Signals consistent with the B⁺_c (2S) and B*_c⁺(2S) states are observed in proton-proton collisions at √s = 13 TeV, in an event sample corresponding to an integrated luminosity of 143 fb⁻¹, collected by the CMS experiment during the 2015–2018 LHC running periods. These excited []c states are observed in the B⁺_c π⁺π⁻ invariant mass spectrum, with the ground state B⁺_c reconstructed through its decay to J/ψπ⁺. The two states are reconstructed as two well-resolved peaks, separated in mass by 29.1 ± 1.5(stat) ± …

Novel Data Analysis Methods In Multi-Channel And Multi-State Binding Experiments, Joseph Tibbs, Elizabeth Boehm, Wayne Bowie, Todd Washington, Maria Spies, Ali Tabei

Research in the Capitol

Single-Molecule studies use advanced microscopy techniques to view biomolecules, such as proteins and DNA, individually. On a slide, fluorescently-labeled molecules are immobilized and imaged using lasers, and the patterns of fluorescence can give important information about the interactions of multiple molecules. To extract this information, advanced, customizable data analysis tools must be created. The first goal is to create a method to robustly normalize (correct for brightness) single-channel fluorescence data. The second goal is to extend pattern recognition of binding order to multi-state and multi-channel binding patterns. The KERA 3.0 suite links creative pattern-recognition and normalization techniques with the abilities …

Quantification Of Contrast-Enhanced Ultrasound, Joseph Pathoulas

All College Thesis Program, 2016-2019

The aim of this experiment was to investigate the effect of manipulating ultrasound scanner settings on time-intensity curve parameters in a tube perfusion phantom system using contrast-enhanced ultrasound imaging. Imaging was performed using a Philips LOGIQ E9 ultrasound scanner equipped with a C1-6VN transducer and utilized two different microbubble contrast agents: Definity and Lumason. The ultrasound scanner settings manipulated included: gain, dynamic range, and frequency. Additionally, relative microbubble concentration, microbubble type, and perfusion flow rate were manipulated. Four time-intensity curve parameters (time to peak, area under curve, gradient, peak intensity) were measured from linearized pixel data. Time to peak was …

Fluctuating Hydrodynamics Of Electrolytes At Electroneutral Scales, Aleksandar Donev, Andrew Nonaka, Changho Kim, Alejandro Garcia, John Bell

Faculty Publications

At mesoscopic scales electrolyte solutions are modeled by the fluctuating generalized Poisson-Nernst-Planck (PNP) equations [J.-P. Péraud et al., Phys. Rev. Fluids 1, 074103 (2016)]. However, at length and time scales larger than the Debye scales, electrolytes are effectively electroneutral and the charged-fluid PNP equations become too stiff to solve numerically. Here we formulate the isothermal incompressible equations of fluctuating hydrodynamics for reactive multispecies mixtures involving charged species in the electroneutral limit and design a numerical algorithm to solve these equations. Our model does not assume a dilute electrolyte solution but rather treats all species on an equal footing, accounting for …

Recent Evolution Of The Eta Carinae Supernova Imposter System, Greta L. Helmel

Physics and Astronomy Honors Projects

The supernova imposter Eta Carinae and its surrounding Homunculus reflection nebula have been of great interest for the last several decades. As the most massive star known in our Galaxy, this object is of particular importance in understanding high mass loss episodes and final stages in the evolution of other similarly massive stars in the later stages of their lives. Observations using the STIS CCD Instrument have been taken over the past 20 years for both the central star and the Homunculus as part of the Hubble Space Telescope (HST) Treasury Program on Eta Carinae. Recent changes in …

Thermodynamic Properties Of Black Holes, Geoffrey Schulthess

Physics Capstone Projects

Black Holes are some of the most mysterious objects in the known universe. In 1975, Stephen Hawking stated that Black Holes can behave as thermodynamical objects with a finite mass, spin, angular velocity, temperature, and entropy. This has been one of the most fascinating yet perplexing breakthroughs in our understanding of these strongly gravitating objects. In this context, the purpose of this research was to use Wolfram Mathematica to create a program that would calculate the thermodynamic properties of a black hole, given a certain metric.

Thermal Oxidation Of Silicon In A Home-Made Furnace System, Joshua Koskan

Physics Capstone Projects

I approached Dr. Shen with a desire for a project in understanding how to manage and expand the capabilities of a laboratory. After some discussion, my senior project was to complete a gas and water chiller system to an existing furnace for chemical vapor deposition. It should be able to handle temperatures up to 1100 ºC, hold a vacuum to mTorr, be easy to move samples in and out of the furnace, and cost effective.

Exploring A Practical Development Of Quantum Computing, Juliano A. Everett, Andrea N. Zambrano, Carlos Aguayza

Publications and Research

Tasked with describing a Quantum architecture (Superconducting loops), we additionally explored how the chosen architecture is used, developed, and how one could get started in understanding the way in which some quantum algorithms work with this architecture through Python and IBM's tools (Qiskit and IBM Q Experience).

Using Symmetry To Accelerate Materials Discovery, Wiley Spencer Morgan

Theses and Dissertations

Computational methods are commonly used by materials scientists to make predictions about materials. These methods can achieve in hours what would take days or weeks to accomplish in a lab. However, there are limits to what computational methods can do and how accurate the predictions are.A limiting factor for computational materials science is the size of the search space. The space of potential materials is infinite. Selecting specific systems of elements on a fixed lattice to study reduces the number of possible arrangements of atoms in the lattice to a finite number. However, this number can still be very large. …

Investigating The Talbot Effect In Arrays Of Optical Dipole Traps For Neutral Atom Quantum Computing, Sergio Aguayo

Physics

Quantum computers are devices that are able to perform calculations not achievable for classical computers. Although there are many methods for creating a quantum computer, using neutral atoms offers the advantage of being stable when compared to other methods. The purpose of this investigation is to explore possible optical dipole trap configurations that would be useful for implementing a quantum computer with neutral atoms. Specifically, we computationally investigate arrays of pinholes, the diffraction pattern generated by them, and the onset of the Talbot effect in these traps. We manipulate the radius of the pinholes, the number of pinholes in the …

Exploring New Fe-Substituted Rare-Earth-Based High Entropy Alloys, Glendon Rewerts

Honors Capstones

No abstract provided.