Digital Commons Network^™

Characterization And Coherent Spin Selective Manipulation Of Quantum Dot Energy Levels, Tristan Anthony Wilkinson

Graduate Theses, Dissertations, and Problem Reports (ETD)

Semiconductor quantum dots (QDs) are promising candidates to fulfill a wide range of applications in real-world quantum computing, communication, and networks. Their excellent optical properties such as high brightness, single-photon purity, and narrow linewidths show potential utility in many areas. In order to realize long term goals of integration into complex and scalable quantum information systems, many current challenges must be overcome. One of these challenges is accomplishment of all necessary computing operations within a QD, which might be enabled by coherent manipulation of single QD energy level structures. In the realm of scalability for quantum devices, a way to …

Ion Velocity Distribution Functions In Cutting-Edge Plasmas, Mitchell Cameron Paul

Graduate Theses, Dissertations, and Problem Reports (ETD)

Cutting-edge plasma experiments continue to push the frontiers of plasma science. Two such groups of experiments, helicon sources and laboratory magnetic reconnection, are the focus of this thesis. The relatively high plasma density achieved for modest input powers makes helicon source plasmas ideal testbeds for fusion-relevant phenomena without the complexities associated with fusion devices. Examples include plasma-material interaction (PMI) studies, divertor region studies, and boundary physics studies. As advancements in helicon source design and technology make operation at higher power for longer times possible, understanding of the plasma dynamics, particularly ion dynamics, is vital.

Laboratory experiments are essential to advancing …

Charge Dynamics Of Inas Quantum Dots Under Resonant And Above-Band Excitation, Gary R. Lander Jr

Graduate Theses, Dissertations, and Problem Reports (ETD)

Research involving light-matter interactions in semiconductor nanostructures has been an interesting topic of investigation for decades. Many systems have been studied for not only probing fundamental physics of the solid state, but also for direct development of technological advancements. Research regarding self-assembled, epitaxially grown quantum dots (QDs) has proven to be prominent in both regards. The development of a reliable, robust source for the production of quantum bits to be utilized in quantum information protocols is a leading venture in the world of condensed matter and solid-state physics. Fluorescence from resonantly driven QDs is a promising candidate for the production …

Microwave Enhanced Electron Energy Distribution Functions, John Samuel Mckee

Graduate Theses, Dissertations, and Problem Reports (ETD)

The use of two (or more) radio frequency (RF) sources at different frequencies is a common technique in the plasma processing industry to control ion energy characteristics separately from plasma generation. A similar approach is presented here with the focus on modifying the electron population in argon and helium plasmas. The plasma is generated by a helicon source at a frequency f0 = 13.56 MHz. Microwaves of frequency f1 = 2.45 GHz are then injected into the helicon source chamber perpendicular to the background magnetic field. The microwaves damp on the electrons via R-mode (anti-parallel to the background magnetic field …

Scaling Theory Of 3d Magnetic Reconnection X-Line Spreading, Milton Arencibia

Graduate Theses, Dissertations, and Problem Reports (ETD)

Magnetic reconnection is fundamental process in plasmas that converts magnetic energy into kinetic and thermal energy via a change in magnetic topology. Magnetic reconnection is known to mediate eruptive solar flares, geomagnetic substorms that create the Northern lights, heating and particle acceleration in controlled fusion devices, and is thought to be an important process in numerous settings in high-energy astrophysics. Classical models of reconnection are two-dimensional (2D), but naturally occurring reconnection is three-dimensional (3D), and a manifestation of the 3D nature is that the x-line where the magnetic field topology changes has a finite extent in the direction normal to …

Reciprocity Of Thermal Diffusion In Time-Modulated Systems, Jiaxin Li, Ying Li, Pei-Chao Cao, Minghong Qi, Xu Zheng, Yu-Gui Peng, Baowen Li, Xue-Feng Zhu, Andrea Alù, Hongsheng Chen, Cheng-Wei Qiu

Advanced Science Research Center

The reciprocity principle governs the symmetry in transmission of electromagnetic and acoustic waves, as well as the diffusion of heat between two points in space, with important consequences for thermal management and energy harvesting. There has been significant recent interest in materials with time-modulated properties, which have been shown to efficiently break reciprocity for light, sound, and even charge diffusion. However, time modulation may not be a plausible approach to break thermal reciprocity, in contrast to the usual perception. We establish a theoretical framework to accurately describe the behavior of diffusive processes under time modulation, and prove that thermal reciprocity …

Polarized Gluon Pseudodistributions At Short Distances, Ian Balitsky, Wayne Morris, Anatoly Radyushkin

Physics Faculty Publications

We formulate the basic points of the pseudo-PDF approach to the lattice calculation of polarized gluon PDFs. We present the results of our calculations of the one-loop corrections for the bilocal G_μα(z)G̃_λβ(0) correlator of gluonic fields. Expressions are given for a general situation when all four indices are arbitrary, and also for specific combinations of indices corresponding to three matrix elements that contain the twist-2 invariant amplitude related to the polarized PDF. We study the evolution properties of these matrix elements, and derive matching relations between Euclidean and light-cone Ioffe-time distributions. These relations are necessary for …

Cebaf Injector Model For KL Beam Conditions, Sunil Pokharel, Geoffrey A. Krafft, A. S. Hofler, R. Kazimi, M. Bruker, J. Grames, S. Zhang

Physics Faculty Publications

The Jefferson Lab KL experiment will run at the Continuous Electron Beam Accelerator Facility with a much lower bunch repetition rate (7.80 or 15.59 MHz) than nominally used (249.5 or 499 MHz). While the proposed average current of 2.5 - 5.0 µA is relatively low compared to the maximum CEBAF current of approximately 180 µA, the corresponding bunch charge is atypically high for CEBAF injector operation. In this work, we investigated the evolution and transmission of low-rep-rate, high-bunch-charge (0.32 to 0.64 pC) beams through the CEBAF injector. Using the commercial software General Particle Tracer, we have simulated and analyzed the …

Study Of The Λ/Σ⁰ Electroproduction In The Low-Q² Region At Jlab, K. Okuyama, K. Itabashi, S. Nagao, S. N. Nakamura, K. N. Suzuki, T. Gogami, B. Pandey, L. Tang, D. Abrams, T. Akiyama, D. Androic, K. Aniol, C. Ayerbe Gayoso, J. Bane, S. Barcus, J. Barrow, V. Bellini, H. Bhatt, D. Bhetuwal, D. Biswas, A. Camsonne, J. Castellanos, J.- P. Chen, J. Chen, S. Covrig, D. Chrisman, R. Cruz-Torres, R. Das, E. Fuchey, K. Gnanvo, F. Garibaldi, T. Gautam, J. Gomez, P. Gueye, T. J. Hague, O. Hansen, W. Henry, Florian Hauenstein, D. W. Higinbotham, Charles E. Hyde, M. Kaneta, C. Keppel, T. Kutz, N. Lashley-Colthirst, S. Li, H. Liu, J. Mammei, P. Markowitz, R. E. Mcclellan, F. Meddi, D. Meekins, R. Michaels, M. Mihovilovic, A. Moyer, D. Nguyen, M. Nycz, V. Owen, C. Palatchi, S. Park, T. Petkovic, S. Premathilake, P. E. Reimer, J. Reinhold, S. Riordan, V. Rodriguez, C. Samanta, S. N. Santiesteban, B. Sawatzky, S. Širca, K. Slifer, T. Su, Y. Tian, Y. Toyama, K. Uehara, G. M. Urciuoli, D. Votaw, J. Williamson, B. Wojtsekhowski, S. A. Wood, B. Yale, Z. Ye, J. Zhang, X. Zheng

Physics Faculty Publications

We performed an experiment using tritium and hydrogen cryogenic gas targets at Thomas Jefferson National Accelerator Facility (JLab) in 2018 (E12-17-003)[1, 2]. In this article, we discuss the Λ/Σ⁰ hyperon electroproduction from hydrogen target. Elementary Λ/Σ⁰ hyperon production processes are important not only for an absolute mass scale calibration in our experiment, but also for the study of the electroproduction mechanisms themselves. In this article, we reported the results of the differential cross section for the p(e, e’K⁺)Λ/Σ⁰ reaction at Q² ∼ 0.5 (GeV/c)².

Cross-Section Measurement Of Virtual Photoproduction Of Iso-Triplet Three-Body Hypernucleus, ⋀Nn, T. Gogami, K. N. Suzuki, B. Pandey, K. Itabashi, S. Nagao, K. Okuyama, S. N. Nakamura, L. Tang, D. Abrams, T. Akiyama, D. Androic, K. Aniol, C. Ayerbe Gayoso, J. Bane, S. Barcus, J. Barrow, V. Bellini, H. Bhatt, D. Bhetuwal, D. Biswas, A. Camsonne, J. Castellanos, J-P. Chen, J. Chen, S. Covrig, D. Chrisman, R. Cruz-Torres, R. Das, E. Fuchey, K. Gnanvo, F. Garibaldi, T. Gautam, J. Gomez, P. Gueye, T.J. Hague, O. Hansen, W. Henry, F. Hauenstein, D. W. Higinbotham, C. E. Hyde, M. Kaneta, C. Keppel, T. Kutz, N. Lashley-Colthirst, S. Li, H. Liu, J. Mammei, P. Markowitz, R. E. Mcclellan, F. Meddi, D. Meekins, R. Michaels, M. Mihovilovic, A. Moyer, D. Nguyen, M. Nycz, V. Owen, C. Palatchi, S. Park, T. Petkovic, S. Premathilake, P.E. Reimer, J. Reinhold, S. Riordan, V. Rodriguez, C. Samanta, S. N. Santiesteban, B. Sawatzky, S. Širca, K. Slifer, T. Su, Y. Tian, Y. Toyama, K. Uehara, G. M. Urciuoli, D. Votaw, J. Williamson, B. Wojtsekhowski, S. A. Wood, B. Yale, Z. Ye, J. Zhang, X. Zheng

Physics Faculty Publications

Missing-mass spectroscopy with the ³H(e, e′K⁺) reaction was carried out at Jefferson Lab’s (JLab) Hall A in Oct–Nov, 2018. The differential cross section for the ³H(γ^∗, K⁺)Λnn was deduced at ω = Ee − E_e′ = 2.102 GeV and at the forward K⁺-scattering angle (0^° ≤ θ_γ∗K ≤ 5^°) in the laboratory frame. Given typical predicted energies and decay widths, which are (B_Λ, Γ) = (−0.25, 0.8) and (−0.55, 4.7) MeV, the cross sections were found …

Improved Electrostatic Design Of The Jefferson Lab 300 Kv Dc Photogun And The Minimization Of Beam Deflection, M. A. Mamun, D. B. Bullard, J. R. Delayen, J. M. Grames, C. Hernandez-Garcia, Geoffrey A. Krafft, M. Poelker, R. Suleiman, S.A.K. Wijethunga

Physics Faculty Publications

An electron beam with high bunch charge and high repetition rate is required for electron cooling of the ion beam to achieve the high luminosity required for the proposed electron-ion colliders. An improved design of the 300 kV DC high voltage photogun at Jefferson Lab was incorporated toward overcoming the beam loss and space charge current limitation experienced in the original design. To reach the bunch charge goal of ~ few nC within 75 ps bunches, the existing DC high voltage photogun electrodes and anode-cathode gap were modified to increase the longitudinal electric field (Ez) at the photocathode. The anode-cathode …

The Effects Of An Ultrafast Pulsed Laser On Ybco Thin Film Circuit Transients, Matthew L. Rustad

Browse all Theses and Dissertations

Terahertz (THz) frequency light has shown promise for a wide variety of applications due to its material characterization and imaging capabilities. Its nondestructive nature coupled with its submillimeter spatial resolution provides the most value for terahertz light as an imaging tool. The application of terahertz technology has been limited by a lack of novel and powerful sources. It has been shown that that Yttrium Barium Copper Oxide (YBCO), a type II superconductor, has certain properties that would allow YBCO to be an effective source for THz light. Recent microwave work has shown that when a persistent supercurrent is placed on …

Third Order Nonlinear Optics In Solids, Nicholas Cox

Electronic Theses and Dissertations, 2020-2023

Nonlinear optical effects occur when strong electromagnetic waves induce changes in a medium that affect its own propagation or that of another wave. Third order optical nonlinearities scale linearly with irradiance and lead to effects like two-photon absorption and nonlinear refraction. This work focuses on the experimental and theoretical study of two-photon absorption in crystalline solids. We begin by detailing the quantum mechanical states of electrons in solids along with the computational approaches to calculate their band structure. Next, a theoretical model for the linear and nonlinear optical interaction of light with matter is presented in a many-body formalism. This …

Optimization-Based Approaches To Low-Coherence Optical Diffraction Tomography, Seth Smith-Dryden

Electronic Theses and Dissertations, 2020-2023

Quantitative optical phase imaging techniques, such as optical diffraction tomography (ODT), are useful tools for refractive-index profiling. Many of them, however, rely on the weak-scattering assumptions, thus cannot be applied to multiple-scattering objects, or turbid media. In this thesis, I report several approaches for expanding the efficacy of ODT techniques and adapting them to new applications by use of low-coherence broadband illumination. First, I developed a method for ODT reconstruction using regularized convex optimization with a new phase-based fidelity criterion. The new criterion is necessary because objects with very different refractive-index distributions may produce similar diffracted fields (magnitude and principal-phase) …

Topical Review: Greybody Factors And Quasinormal Modes For Black Holes Invarious Theories - Fingerprints Of Invisibles, İzzet Sakalli, Sara Kanzi

Turkish Journal of Physics

We give a pedagogical introduction to black holes (BHs) greybody factors (GFs) and quasinormal modes (QNMs) and share the recent developments on those subjects. To this end, we present some particular analytical and approximation techniques for the computations of the GFs and QNMs. We first review the gravitational GFs and show how they are analytically calculated for static and spherically symmetric higher dimensional BHs, consisting the charged BHs and existence of cosmological constant (i.e. de Sitter (dS)/anti-de Sitter (AdS)AdS BHs). The computations performed involve both the low-energy (having real and small frequencies) and the asymptotic (having extremely high frequency of …

Extinction And Growth On An Inhomogeneous Seascape, Tung Tran, Mehran Kardar

Turkish Journal of Physics

The effects of noise and nonuniformity on dynamics of populations are relevant and timely subjects of investigation. One form of variation is the time dependence of the reproduction rate (fitness), referred to as ?seascape? noise; another is time-independent intrinsic dependencies of fitness on location (in the parlance of statistical physics, corresponding to annealed and quenched disorder, respectively). The former was studied recently and demonstrated to lead to novel universality classes for extinction and growth. To reduce the gap between this theoretical model and reality, we develop a new formalism for seascape noise where growth and migration parameters are inhomogeneous. In …

On An Econophysics Model, Miron Kaufman

Turkish Journal of Physics

Krugman has proposed a continuous in time and space model for the emergence of polycentric urban areas in the regional space. By using a discrete version of this model on spatial networks, we predicted the distribution of jobs among the different localities inside a couple of economic regions in Ohio and Texas. The time evolution of the distribution of jobs is governed by a market potential. Employment gradually moves towards locations considered relatively attractive if their market potential is above the spatial average. Similarly, jobs move away from locations with below-average market potential. First, I will show that the market …

What Happens When Transition Metal Trichalcogenides Are Interfaced With Gold?, Archit Dhingra, Dmitri E. Nikonov, Alexey Lipatov, Alexander Sinitskii, Peter Dowben

Peter Dowben Publications

Transition metal trichalcogenides (TMTs) are two-dimensional (2D) systems with quasi-one-dimensional (quasi-1D) chains. These 2D materials are less susceptible to undesirable edge defects, which enhances their promise for low-dimensional optical and electronic device applications. However, so far, the performance of 2D devices based on TMTs has been hampered by contact-related issues. Therefore, in this review, a diligent effort has been made to both elucidate and summarize the interfacial interactions between gold and various TMTs, namely, In₄Se₃, TiS₃, ZrS₃, HfS₃, and HfSe₃. X-ray photoemission spectroscopy data, supported by the results …

Direct Observation Of Ferroelectric Switching In Two-Dimensional Mos2, A. Lipatov, P. Chaudhary, Z. Guan, H. Lu, G. Li, O. Crégut, K. D. Dorkenoo, R. Proksch, Ding-Fu Shao, Evgeny Y. Tsymbal, J. Íñiguez, A. Sinitskii, Alexei Gruverman

Evgeny Tsymbal Publications

No abstract provided.

Nonlinear Light - Matter Interactions Of Ultrafast High Intensity Laser Pulses, Henry Meyer

Dissertations and Theses

This thesis focuses on the key nonlinear optical effects that arise from the interactions of intense ultrafast laser pulses with various states of matter. These interactions involve electronic and molecular states and yield new information on the underlying fundamental processes that govern the molecular world. Modern day lasers offer ultrashort pulses, high intensities, and complex polarizations and wavefronts. These extreme conditions have profound effect on the optical properties and behaviors of electronic and molecular states within a material. The changes in these mechanisms effect generation of nonlinear optics, such supercontinuum (SC), stimulated Raman (SRS), self-focusing and filamentation, conical emission (CE), …

Parallels Of Quantum Mechanics And Mahāyāna Buddhist Philosophy: An Argument For Relational Quantum Mechanics, Axel I. Palapa

CMC Senior Theses

Western orthodoxy philosophy is based on the principle of noncontradiction and thus, the philosophy of science is as well. The most prominent interpretations of quantum mechanics, since its inception, have followed this principle. In this paper, two quantum phenomena, the Observer Problem (measurement problem) and quantum entanglement will be analyzed from a Mahayana Buddhism ontological perspective. I will analyze the mathematical and philosophical arguments proposed by Graham Priest and Jay Garfield, based on dialethism, pertaining to Nagarjuna and the Net of Indra. Demonstrating the parallels and adaptability of the arguments to further the philosophical groundwork for Carlo Reveille’s Relational Quantum …

Periodic Trends In The Infrared And Optical Absorption Spectra Of Metal Chalcogenide Clusters, Alain Ward

Theses and Dissertations

We have investigated the Optical absorption, Infrared spectra, Binding Energies, and various other cluster properties to determine the existence of periodic trend for Transition Metal Chalcogenide Clusters ligated with CO ligands. We were motivated to answer the question of whether periodic behavior can be observed in properties of octahedral metal-chalcogenide clusters. We have used the Amsterdam Density Functional code to calculate the electronic structure of Transition Metal Chalcogenide Clusters using gradient-corrected density functional theory. We determined the existence of several periodic trends in properties of octahedral Transition Metal Chalcogenide Clusters TM₆Se₈(CO)₆. To investigate these …

Direction Modulated Brachytherapy For The Treatment Of Cervical Cancer, Dylan Richeson

Theses and Dissertations

Purpose: To evaluate and compare the performance of 9 experimental DMBT tandem models of varying physical dimensions in relation to 24 previously planned HDR cervical cancer treatment plans from multiple institutions that used conventional tandem and rings or ovoid applicators.

Methods and Materials: The DMBT tandem is designed to be used concurrently with IGABT and is made from an MRI-compatible tungsten-alloy rod with 6 channels grooved out of its periphery. 9 experimental DMBT tandem prototypes were provided. Each of the models was of equal lengths but varied in thickness, channel diameter size, and circle channel diameter size. Replanning …

Precise Phase Space Control For Future Linear Colliders, Tianzhe Xu

Graduate Research Theses & Dissertations

The design of future linear colliders is highly constrained by their cost and footprint. Phase space partitioning offers an attractive path towards cost and complexity reduction through precise tailoring of particle beam distributions. In this dissertation, we discuss a phase space manipulation technique for generating flat electron beams---a type of beam distribution of particular interest to linear colliders. We report the experimental generation of flat beams with transverse-emittance ratio up to 200 at Argonne Wakefield Accelerator facility. We further expand the technique by combining it with transverse-to-longitudinal emittance exchange. We present the conceptual design of an electron injector capable of …

Search For Charged Higgs Bosons In The Tau+Nu Final State With 139 Inverse Fb Of Pp Collision Data At Sqrt(S)=13 Tev With The Atlas Experiment, Elliot Wesley Parrish

Graduate Research Theses & Dissertations

This dissertation uses 139 inverse fb of pp collision data collected at a center of mass energy of sqrt(s)=13 TeV by the ATLAS detector to search for charged Higgs bosons decaying to a tau lepton and a neutrino in association with a top quark. Two subchannels are defined based on the leptonic decay (tau+lepton) or hadronic decay (tau+jets) of the associated top quark. Parameterized Neural Networks are investigated and optimized to improve signal separation from background in both subchannels across a wide charged Higgs boson mass range of 80 GeV to 3000 GeV. Expected exclusion limits at 95% confidence on …

Studies Of Vector Boson Scattering In The Semileptonic Zv Channel With The Cms Detector At √S = 13 Tev, Ramanpreet Singh

Graduate Research Theses & Dissertations

This dissertation reports on the search for the vector boson scattering (VBS) in semileptonicZV channel, where the Z boson decays to a pair of leptons (electrons or muons), and the other vector boson V (either W or Z) decays hadronically to a pair of jets, in association of two large pseudorapidity jets i.e. ZVjj → l+l−jjjj, l = e or μ. The search used 137 fb−1 of proton-proton collision data collected by the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) with center-of-mass energy (√s) of 13 TeV from 2016 to 2018. VBS is a key process …

Searching For An Enhanced Signal Of The Onset Of Color Transparency In Baryons With D(E,E′P)N Scattering, Shujie Li, Carlos Yero, Jennifer Rittenhouse West, Clare Bennett, Wim Cosyn, Douglas Higinbotham, Misak Sargsian, Holly Szumila-Vance

Physics Faculty Publications

Observation of the onset of color transparency in baryons would provide a new means of studying the nuclear strong force and would be the first clear evidence of baryons transforming into a color-neutral point-like size in the nucleus as predicted by quantum chromodynamics. Recent C (e, e′p) results from electron-scattering did not observe the onset of color transparency (CT) in protons up to spacelike four-momentum transfers squared, Q² = 14.2 GeV ² . The traditional methods of searching for CT in (e, e′p) scattering use heavy targets favoring kinematics with already initially reduced final state interactions (FSIs) such that …

Enhancements To Uniformity Of Magnetic Fields At The Sns Nedm Experiment, Ahmad Saftah

Theses and Dissertations--Physics and Astronomy

The nEDM experiment at the Spallation Neutron Source (SNS) aims to increase
experimental sensitivity to hadronic CP violation by nearly two orders of magnitude.To do that the nEDMSNS experiment requires an extremely uniform magnetic field to maintain ³He polarization during transit to the measurement cell. The Magnetic Shield Enclosure (MSE) coil provides the required field. However, the superconducting shield distorts the MSE field.

This thesis discusses a magnetic cloak for the nEDM@SNS experiment that can restore the MSE field uniformity and cos theta coils designed to test the magnetic cloak in the first part. The second part of this …

Angular Distribution Of Electron-Helium Scattering In The Presence Of A 1.17 Ev Laser Field, Brian N. Kim

Theses and Dissertations--Physics and Astronomy

We have measured relative differential cross sections for 350 eV electrons scattered by a helium target in the presence of 1.17 eV photons from an Nd:YAG laser. We report an angular distribution of free-free electrons that were scattered elastically at angles between 15^o and 80^o and of free-free electrons that underwent the process of electron-impact excitation of helium to its unresolved (1s2s)¹S and (1s2p)¹P excited states at angles between 1^o and 80^o. Our experiments test the momentum transfer dependence and the relationship between elastic and inelastic scattering in the Kroll-Watson approximation. …

An Energy-Integrated Analysis For Measuring The Anomalous Precession Frequency For The Muon G − 2 Experiment At Fermilab, Laura Kelton

Theses and Dissertations--Physics and Astronomy

In the search for physics beyond the Standard Model, the Muon g − 2 Experiment at Fermilab (E989) will make the most precise measurement of the anomalous magnetic moment of the muon, a_μ. Improvements in precision come from both increased statistics and new techniques to significantly reduce previous systematic uncertainties. The muon a_μ is determined by extracting both the anomalous spin precession frequency, ω_a, and the average magnetic field sampled by the muons, B. Traditionally an energy threshold analysis method which requires reconstruction of decay positrons from the muon decay, μ⁺ → e^{+ …}