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Full-Text Articles in Physics

Physics And Mathematics Of Graded Quivers, Azeem Hasan Sep 2019

Physics And Mathematics Of Graded Quivers, Azeem Hasan

All Dissertations, Theses, and Capstone Projects

A graded quiver with superpotential is a quiver whose arrows are assigned degrees c ∈ {0, 1, · · · , m}, for some integer m ≥ 0, with relations generated by a superpotential of degree m − 1. For m = 0, 1, 2, 3 they often describe the open string sector of D-brane systems; in particular, they capture the physics of D(5 − 2m)-branes at local Calabi-Yau (CY) (m + 2)- fold singularities in type IIB string theory. We introduce m-dimers, which fully encode the m-graded quivers and their superpotentials, in the case in which the CY (m + 2)-folds are toric. A key result is ...


Sequential Discrimination Between Non-Orthogonal Quantum States, Dov L. Fields Sep 2019

Sequential Discrimination Between Non-Orthogonal Quantum States, Dov L. Fields

All Dissertations, Theses, and Capstone Projects

The problem of discriminating between non-orthogonal states is one that has generated a lot of interest. This basic formalism is useful in many areas of quantum information. It serves as a fundamental basis for many quantum key distribution schemes, it functions as an integral part of other quantum algorithms, and it is useful in experimental settings where orthogonal states are not always possible to generate. Additionally, the discrimination problem reveals important fundamental properties, and is intrinsically related to entanglement. In this thesis, the focus is on exploring the problem of sequentially discriminating between non-orthogonal states. In the simplest version these ...


On Different Parametrizations Of Feynman Integrals, Ray Daniel Sameshima Sep 2019

On Different Parametrizations Of Feynman Integrals, Ray Daniel Sameshima

All Dissertations, Theses, and Capstone Projects

In this doctoral thesis, we discuss and apply advanced techniques for the calculations of scattering amplitudes which, on the one hand, allow us to compute cross sections and differential distributions at high precision and, on the other hand, give us deep mathematical insights on the mathematical structures of Feynman integrals.

We start by presenting phenomenological calculations relevant for the experimental analyses at the Large Hadron Collider. We use the resummation of soft gluon emission corrections to study the associated production of a top pair and a Z boson to next-to-next-to-leading logarithmic accuracy, and compute the total cross section and differential ...


Optical And Collective Properties Of Excitons In 2d Semiconductors, Matthew N. Brunetti Sep 2019

Optical And Collective Properties Of Excitons In 2d Semiconductors, Matthew N. Brunetti

All Dissertations, Theses, and Capstone Projects

We study the properties of excitons in 2D semiconductors (2DSC) by numerically solving the Schr\"{o}dinger equation for an interacting electron and hole in the effective mass approximation, then calculating optical properties such as the transition energies, oscillator strengths, and absorption coefficients. Our theoretical approach allows us to consider both direct excitons in monolayer (ML) 2DSC and spatially indirect excitons in heterostructures (HS) consisting of two 2DSC MLs separated by few-layer insulating hexagonal boron nitride (h-BN). In particular, we study indirect excitons in TMDC HS, namely MoS2, MoSe2, WS2, and WSe2; both direct and ...


Coulomb Excitation And Transport Properties Of Monolayer Graphene And The Alpha-T3 Lattice, Dipendra Dahal Sep 2019

Coulomb Excitation And Transport Properties Of Monolayer Graphene And The Alpha-T3 Lattice, Dipendra Dahal

All Dissertations, Theses, and Capstone Projects

In the past few years, I focused my attention in the study of 2D material's behavior, specifically graphene . We investigated several properties of graphene like transmission of particle through a potential barrier and demonstrated the effect of band gap to suppress the Klein tunneling at head on collision, we presented the results to get the criteria of negative refractive index and Klein tunneling through multiple barrier. Next, we have carried out the calculation of polarization function of graphene in the presence of magnetic field. The effect of integer Landau filling factor is shown and the portrayed results are presented ...


Inference Of Language Functional Network In Healthy, Cancerous And Bilingual Brains By Fmri And Network Modeling, Qiongge Li Sep 2019

Inference Of Language Functional Network In Healthy, Cancerous And Bilingual Brains By Fmri And Network Modeling, Qiongge Li

All Dissertations, Theses, and Capstone Projects

We study the underlying mechanism by which language processing occurs in the human brain using inference methods on functional magnetic resonance imaging data. The data analyzed stems from several cohorts of subjects; a monolingual group, a bilingual group, a healthy control group and one diseased case. We applied a complex statistical inference pipeline to determine the network structure of brain components involved with language. This healthy network reveals a fully connected triangular relationship between the pre-Supplementary Motor Area (pre-SMA), the Broca's Area (BA), and the ventral Pre-Motor Area (PreMA) in the left hemisphere. This "triangle'' shows consistently in all ...


Nuclear Magnetic Resonance Characterization Of Dynamics In Novel Electrochemical Materials, Christopher T. Mallia May 2019

Nuclear Magnetic Resonance Characterization Of Dynamics In Novel Electrochemical Materials, Christopher T. Mallia

School of Arts & Sciences Theses

As our daily use of electronics and electronic technology grows, so does the societal need for sustainable, renewable and portable electrical power. To this end, materials of interest in the electrochemical world are needed to advance the frontier of battery science and energy storage technologies so that a safer, more efficient and reliable electrical future can be realized. This work focuses on characterization of materials primarily of interest for use as electrolytes in rechargeable Lithium-Ion Batteries (LIBs). Despite their extraordinary power, LIB application in certain fields, such as in electric vehicles, has been limited due to performance and safety concerns ...


Emergent Critical Properties In Liquid-Gas Transition And Single Dislocations In Solid He4, Max Yarmolinsky Feb 2019

Emergent Critical Properties In Liquid-Gas Transition And Single Dislocations In Solid He4, Max Yarmolinsky

All Dissertations, Theses, and Capstone Projects

My research focuses on the analytical and numerical study of seemingly completely different systems - the classical critical point of the liquid-gas transition and a quantum topological defect (dislocation) in solid Helium-4. The unifying theme, though, is Emergence - the appearance of unexpected qualities at large distance and time scales in these systems. Our results resolve the long standing controversy about the nature of the liquid-gas criticality by showing with high confidence that it is the same as that of Ising ferromagnet. In solid 4He, a quantum superclimbing dislocation, which is expected to be violating space-time symmetry according to the elementary ...


Magnetic Resonance Studies Of Free Radicals Generation And Their Impact In Different Polymers, Sunita Humagain Feb 2019

Magnetic Resonance Studies Of Free Radicals Generation And Their Impact In Different Polymers, Sunita Humagain

All Dissertations, Theses, and Capstone Projects

Studies of free radicals in the physics, chemistry, biology, and materials science have contributed to advancements in those fields. The presence of radicals can damage the material and system in some instances and, in some cases, they may enhance the property of the material as well. Knowledge of free radical transformations helps in resilience of certain polymers and inhibition of the oxidation of food and medicine. In this thesis, using the magnetic resonance techniques, EPR and NMR, the generation of free radicals and their effect on the structure of the material is being studied.

Kapton Polyimide (PI, Kapton®) used in ...


Control Of Light-Matter Interactions Via Nanostructured Photonic Materials, Nicholas Proscia Feb 2019

Control Of Light-Matter Interactions Via Nanostructured Photonic Materials, Nicholas Proscia

All Dissertations, Theses, and Capstone Projects

The thesis here investigates the manipulation of light-matter interactions via nanoscale engineering of material systems. When material systems are structured on the nanoscale, their optical responses can be dramatically altered. In this thesis, this is done in two primary ways: One method is by changing the geometry of nanostructures to induce a resonant behavior with incident electromagnetic field of optical wavelengths. This allows field enhancement in highly localized areas to strengthen exotic light-matter interactions that would otherwise be too weak to measure or for practical use. In this regard, the work presented here studies a voltage produced in a metal ...


Peculiar Optical Properties Of Bilayer Silicene Under The Influence Of External Electric And Magnetic Fields, Thi-Nga Do, Godfrey Gumbs, Po-Hsin Shih, Danhong Huang, Chih-Wei Chiu, Chia-Yun Chen, Ming-Fa Lin Jan 2019

Peculiar Optical Properties Of Bilayer Silicene Under The Influence Of External Electric And Magnetic Fields, Thi-Nga Do, Godfrey Gumbs, Po-Hsin Shih, Danhong Huang, Chih-Wei Chiu, Chia-Yun Chen, Ming-Fa Lin

Publications and Research

We conduct a comprehensive investigation of the effect of an applied electric field on the optical and magneto-optical absorption spectra for AB-bt (bottom-top) bilayer silicene. The generalized tightbinding model in conjunction with the Kubo formula is efficiently employed in the numerical calculations. The electronic and optical properties are greatly diversified by the buckled lattice structure, stacking configuration, intralayer and interlayer hopping interactions, spin-orbital couplings, as well as the electric and magnetic fields (Ez ˆz & Bz ˆz ). An electric field induces spin-split electronic states, a semiconductor-metal phase transitions and the Dirac cone formations in different valleys, leading to the special absorption ...


Computational Techniques For Scattering Amplitudes, Juliano A. Everett Dec 2018

Computational Techniques For Scattering Amplitudes, Juliano A. Everett

Publications and Research

Scattering amplitudes in quantum field theory can be described as the probability of a scattering process to happen within a high energy particle interaction, as well as a bridge between experimental measurements and the prediction of the theory.

In this research project, we explore the Standard Model of Particle Theory, it’s representation in terms of Feynman diagrams and the algebraic formulas associated with each combination.

Using the FeynArts program as a tool for generating Feynman diagrams, we evaluate the expressions of a set of physical processes, and explain why these techniques become necessary to achieve this goal.


Impact Of Fiber Parameters On Edfa And/Or Raman Amplified High-Spectral-Efficiency Coherent Wdm Transmissions, Lufeng Leng Nov 2018

Impact Of Fiber Parameters On Edfa And/Or Raman Amplified High-Spectral-Efficiency Coherent Wdm Transmissions, Lufeng Leng

Publications and Research

The impact of fiber properties is investigated for coherent systems employing polarization-division multiplexed high-level quadrature amplitude modulation, wavelength-division multiplexing, and erbium-doped fiber amplifier and/or distributed Raman amplification. This is done by comparing the performances of fiber links of various attenuation coefficients and effective areas via experimentally verified analytical methods. Results show that the excess noise, which originates at amplifiers compensating for the losses of filters and switches located between fiber spans, can weaken or even diminish the performance enhancement brought about by lowering the fiber attenuation coefficient, especially if distributed Raman amplification is employed. This leads to the difference ...


The Diverse Magneto-Optical Selection Rules In Bilayer Black Phosphorus, Jhao-Ying Wu, Szu-Chao Chen, Thi-Nga Do, Wu-Pei Su, Godfrey Gumbs, Ming-Fa Lin Sep 2018

The Diverse Magneto-Optical Selection Rules In Bilayer Black Phosphorus, Jhao-Ying Wu, Szu-Chao Chen, Thi-Nga Do, Wu-Pei Su, Godfrey Gumbs, Ming-Fa Lin

Publications and Research

The magneto-optical properties of bilayer phosphorene is investigated by the generalized tight-binding model and the gradient approximation. The vertical inter-Landau-level transitions, being sensitive to the polarization directions, are mainly determined by the spatial symmetries of sub-envelope functions on the distinct sublattices. The anisotropic excitations strongly depend on the electric and magnetic fields. A uniform perpendicular electric field could greatly diversify the selection rule, frequency, intensity, number and form of symmetric absorption peaks. Specifically, the unusual magneto-optical properties appear beyond the critical field as a result of two subgroups of Landau levels with the main and side modes. The rich and ...


Quantum And Classical Transport Of 2d Electrons In The Presence Of Long And Short Range Disorder, Jesse Kanter Sep 2018

Quantum And Classical Transport Of 2d Electrons In The Presence Of Long And Short Range Disorder, Jesse Kanter

All Dissertations, Theses, and Capstone Projects

This work focuses on the study of electron transport of 2-D electron gas systems in relation to both fundamental properties of the systems such as disorder and scattering mechanisms, as well as unique magnetoresistance (MR) effects. A large portion of the discussion is built around the use of an in plane magnetic field to vary the ratio between the Zeeman energy between electrons of different spins and the Landau level spacing, creating a tool to control the quantization of the density of states (DOS).

This tool is first used to isolate Quantum Positive Magnetoresistance (QPMR), which grants insight to the ...


Charge State Dynamics And Quantum Sensing With Defects In Diamond, Jacob D. Henshaw Sep 2018

Charge State Dynamics And Quantum Sensing With Defects In Diamond, Jacob D. Henshaw

All Dissertations, Theses, and Capstone Projects

In recent years, defect centers in wide band gap semiconductors such as diamond, have received significant attention. Defects offer great utility as single photon emitters, nanoscale sensors, and quantum memories and registers for quantum computation. Critical to the utility of these defects, is their charge state.

In this dissertation, experiments surrounding the charge state dynamics and the carrier dynamics are performed and analyzed. Extensive studies of the ionization and recombination processes of defects in diamond, specifically, the Nitrogen Vacancy (NV) center, have been performed. Diffusion of ionized charge carriers has been imaged indirectly through the recapture of said carriers by ...


Nmr Characterizations Of Candidate Battery Electrolytes, Stephen A. Munoz Sep 2018

Nmr Characterizations Of Candidate Battery Electrolytes, Stephen A. Munoz

All Dissertations, Theses, and Capstone Projects

Enormous strides have been made in next-generation power sources to build a more sustainable society. Energy storage has become a limiting factor in our progress, and there are huge environmental and financial incentives to find the next step forward in battery technology. This work discusses NMR methods for characterizing materials for use in battery application, with a special focus on relaxometry and diffusometry. Examples are provided of various recent investigations involving novel candidate electrolyte materials with different collaborators. Works discussed in this thesis include: the characterization of a new disruptive solid polymer electrolyte technology, investigations of the dynamics of super ...


A Network Theoretical Approach To Real-World Problems: Application Of The K-Core Algorithm To Various Systems, Kate Burleson-Lesser Sep 2018

A Network Theoretical Approach To Real-World Problems: Application Of The K-Core Algorithm To Various Systems, Kate Burleson-Lesser

All Dissertations, Theses, and Capstone Projects

The study of complex networks is, at its core, an exploration of the mechanisms that control the world in which we live at every scale, from particles no bigger than a grain of sand and amino acids that comprise proteins, to social networks, ecosystems, and even countries. Indeed, we find that, regardless of the physical size of the network's components, we may apply principles of complex network theory, thermodynamics, and statistical mechanics to not only better understand these specific networks, but to formulate theories which may be applied to problems on a more general level. This thesis explores several ...


Finding Paths Via Quantum Systems And Its Application For Quantum Algorithms, Daniel S. Koch May 2018

Finding Paths Via Quantum Systems And Its Application For Quantum Algorithms, Daniel S. Koch

All Dissertations, Theses, and Capstone Projects

The field of Quantum Information Theory provides the theoretical foundation for the pursuit of quantum computers. The ongoing questions of how quantum computers will be realized and what they will achieve, are both very uncertain. However, worldwide efforts are beginning to converge on some answers, and the future of quantum computers is looking brighter than ever. In contribution to the grand goal that is quantum computing, this thesis serves as a demonstration to the usefulness of quantum over classical computing. The central theme of my work, and my collaborators, is the exploration of using quantum systems as a tool for ...


The Advection-Diffusion Equation And The Enhanced Dissipation Effect For Flows Generated By Hamiltonians, Michael Kumaresan May 2018

The Advection-Diffusion Equation And The Enhanced Dissipation Effect For Flows Generated By Hamiltonians, Michael Kumaresan

All Dissertations, Theses, and Capstone Projects

We study the Cauchy problem for the advection-diffusion equation when the diffusive parameter is vanishingly small. We consider two cases - when the underlying flow is a shear flow, and when the underlying flow is generated by a Hamiltonian. For the former, we examine the problem on a bounded domain in two spatial variables with Dirichlet boundary conditions. After quantizing the system via the Fourier transform in the first spatial variable, we establish the enhanced-dissipation effect for each mode. For the latter, we allow for non-degenerate critical points and represent the orbits by points on a Reeb graph, with vertices representing ...


Optimization Of Cuinxga1-Xse2 Solar Cells With Post Selenization, Zehra Cevher May 2018

Optimization Of Cuinxga1-Xse2 Solar Cells With Post Selenization, Zehra Cevher

All Dissertations, Theses, and Capstone Projects

The chalcopyrite semiconductor CuInxGa1-xSe2 is considered as the most promising material for high efficiency thin film solar cells due to its exceptional radiation stability, tunable direct bandgap, high light absorption coefficient and low cost preparation methods. In this thesis, we present the systematic investigation of the deposition conditions to optimize the CuInxGa1-xSe2 device performance using the two-step deposition method. Further, we utilized nonlinear optical methods to investigate the deposition parameters to optimize the bulk and interface properties of photovoltaic devices.

First, we investigated the deposition parameters to optimize the structural ...


Physical Applications Of The Geometric Minimum Action Method, George L. Poppe Jr. May 2018

Physical Applications Of The Geometric Minimum Action Method, George L. Poppe Jr.

All Dissertations, Theses, and Capstone Projects

This thesis extends the landscape of rare events problems solved on stochastic systems by means of the \textit{geometric minimum action method} (gMAM). These include partial differential equations (PDEs) such as the real Ginzburg-Landau equation (RGLE), the linear Schroedinger equation, along with various forms of the nonlinear Schroedinger equation (NLSE) including an application towards an ultra-short pulse mode-locked laser system (MLL).

Additionally we develop analytical tools that can be used alongside numerics to validate those solutions. This includes the use of instanton methods in deriving state transitions for the linear Schroedinger equation and the cubic diffusive NLSE.

These analytical solutions ...


Pregnancy Induced Alterations Of Reproductive Tract Collagen And Elastin In A Murine Model, Basant K. Dhital May 2018

Pregnancy Induced Alterations Of Reproductive Tract Collagen And Elastin In A Murine Model, Basant K. Dhital

All Dissertations, Theses, and Capstone Projects

This thesis reports on structural and dynamical modifications of reproductive tract elastin and collagen as a function of parity. Pelvic floor dysfunction, including pelvic organ prolapse (POP) is a major concern affecting female health worldwide, leading to surgeries costing billions of dollars annually. Collagen, elastic fibers, and proteoglycans are major extracellular matrix (ECM) components found in connective tissues. Vaginal child birth, advancing age, and disruption or dysfunction of connective tissue are major risk factors of POP. In the female reproductive tract, the assembly of elastic fibers is crucial for the pelvic floor support. Any disturbance in the synthesis, assembly, and ...


N-Representability In The Quantum Kernel Energy Method, Walter Polkosnik May 2018

N-Representability In The Quantum Kernel Energy Method, Walter Polkosnik

All Dissertations, Theses, and Capstone Projects

The Kernel Energy Method (KEM) delivers accurate full molecule energies using less computational resources than standard ab-initio quantum chemical approaches. KEM achieves this efficiency by decomposing a system of atoms into disjoint subsets called kernels. The results of full ab-initio calculations on each individual single kernel and on each double kernel formed by the union of each pair of single kernels are combined in an equation of a form that is specific to KEM to provide an approximation to the full molecule energy. KEM has been demonstrated to give accurate molecular energies over a wide range of systems, chemical methods ...


Standard And Anomalous Wave Transport Inside Random Media, Xujun Ma May 2018

Standard And Anomalous Wave Transport Inside Random Media, Xujun Ma

All Dissertations, Theses, and Capstone Projects

This thesis is a study of wave transport inside random media using random matrix theory. Anderson localization plays a central role in wave transport in random media. As a consequence of destructive interference in multiple scattering, the wave function decays exponentially inside random systems. Anderson localization is a wave effect that applies to both classical waves and quantum waves. Random matrix theory has been successfully applied to study the statistical properties of transport and localization of waves. Particularly, the solution of the Dorokhov-Mello-Pereyra-Kumar (DMPK) equation gives the distribution of transmission.

For wave transport in standard one dimensional random systems in ...


Multi Institutional Quantitative Phantom Study Of Yttrium-90 Pet In Pet/Mri: The Mr-Quest Study, Nicole M. Maughan, Mootaz Eldib, David Faul, Maurizio Conti, Mattijs Elschot, Karin Knešaurek, Francesca Leek, David Townsend, Frank P. Difilippo, Kimberly Jackson, Stephan G. Nekolla, Mathias Lukas, Michael Tapner, Parag J. Parikh, Richard Laforest Apr 2018

Multi Institutional Quantitative Phantom Study Of Yttrium-90 Pet In Pet/Mri: The Mr-Quest Study, Nicole M. Maughan, Mootaz Eldib, David Faul, Maurizio Conti, Mattijs Elschot, Karin Knešaurek, Francesca Leek, David Townsend, Frank P. Difilippo, Kimberly Jackson, Stephan G. Nekolla, Mathias Lukas, Michael Tapner, Parag J. Parikh, Richard Laforest

Publications and Research

Background

Yttrium-90 (90Y) radioembolization involves the intra-arterial delivery of radioactive microspheres to treat hepatic malignancies. Though this therapy involves careful pre-treatment planning and imaging, little is known about the precise location of the microspheres once they are administered. Recently, there has been growing interest post-radioembolization imaging using positron-emission tomography (PET) for quantitative dosimetry and identifying lesions that may benefit from additional salvage therapy. In this study, we aim to measure the inter-center variability of 90Y PET measurements as measured on PET/MRI in preparation for a multi-institutional prospective phase I/II clinical trial.

Eight institutions participated in this ...


Diy Science Sims, James Hedberg Apr 2018

Diy Science Sims, James Hedberg

Open Educational Resources

No abstract provided.


Dissipation Effects In Schrödinger And Quantal Density Functional Theories Of Electrons In An Electromagnetic Field, Xiao-Yin Pan, Viraht Sahni Mar 2018

Dissipation Effects In Schrödinger And Quantal Density Functional Theories Of Electrons In An Electromagnetic Field, Xiao-Yin Pan, Viraht Sahni

Publications and Research

Dissipative effects arise in an electronic system when it interacts with a time-dependent environment. Here, the Schrödinger theory of electrons in an electromagnetic field including dissipative effects is described from a new perspective. Dissipation is accounted for via the effective Hamiltonian approach in which the electron mass is time-dependent. The perspective is that of the individual electron: the corresponding equation of motion for the electron or time-dependent differential virial theorem—the ‘Quantal Newtonian’ second law—is derived. According to the law, each electron experiences an external field comprised of a binding electric field, the Lorentz field, and the electromagnetic field ...


Investigation Of Novel Electrolytes For Use In Lithium-Ion Batteries And Direct Methanol Fuel Cells, Kartik Pilar Feb 2018

Investigation Of Novel Electrolytes For Use In Lithium-Ion Batteries And Direct Methanol Fuel Cells, Kartik Pilar

All Dissertations, Theses, and Capstone Projects

Energy storage and conversion plays a critical role in the efficient use of available energy and is crucial for the utilization of renewable energy sources. To achieve maximum efficiency of renewable energy sources, improvements to energy storage materials must be developed. In this work, novel electrolytes for secondary batteries and fuel cells have been studied using nuclear magnetic resonance and high pressure x-ray scattering techniques to form a better understanding of dynamic and structural properties of these materials. Ionic liquids have been studied due to their potential as a safer alternative to organic solvent-based electrolytes in lithium-ion batteries and composite ...


Effects Of Structural And Electronic Disorder In Topological Insulator Sb2te3 Thin Films, Inna Korzhovska Feb 2018

Effects Of Structural And Electronic Disorder In Topological Insulator Sb2te3 Thin Films, Inna Korzhovska

All Dissertations, Theses, and Capstone Projects

Topological quantum matter is a unique and potentially transformative protectorate against disorder-induced backscattering. The ultimate disorder limits to the topological state, however, are still not known - understanding these limits is critical to potential applications in the fields of spintronics and information processing. In topological insulators spin-orbit interaction and time-reversal-symmetry invariance guarantees - at least up to a certain disorder strength - that charge transport through 2D gapless Dirac surface states is robust against backscattering by non-magnetic disorder. Strong disorder may destroy topological protection and gap out Dirac surface states, although recent theories predict that under severe electronic disorder a quantized topological conductance ...