Physics Commons^™

Static Solid Relaxation Ordered Spectroscopy: Ss-Rosy, Gregory S. Boutis, Ravinath Kausik

Publications and Research

A two-dimensional pulse sequence is introduced for correlating nuclear magnetic resonance anisotropic chemical shifts to a relaxation time (e.g., T1) in solids under static conditions. The sequence begins with a preparatory stage for measuring relaxation times, and is followed by a multiple pulse sequence for homonuclear dipolar decoupling. Data analysis involves the use of Fourier transform, followed by a one-dimensional inverse Laplace transform for each frequency index. Experimental results acquired on solid samples demonstrate the general approach, and additional variations involving heteronuclear decoupling and magic angle spinning are discussed.

Graded Quivers, Generalized Dimer Models And Toric Geometry, Sebastián Franco, Azeem Hasan

Publications and Research

The open string sector of the topological B-model on CY (m+2)-folds is described by m-graded quivers with superpotentials. This correspondence extends to general m the well known connection between CY (m+2)-folds and gauge theories on the world-volume of D(5-2m)-branes for m = 0, ..., 3. 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. Generalizing the well known m = 1,2 cases, m-dimers significantly simplify the connection between geometry and m-graded quivers. A key …

Planck's And Callendar's Blackbody Radiation Formulas And Their Fitness To Experimental Data, Max Tran

Publications and Research

In this paper, we compare the blackbody radiation density formula obtained with classical physics by Hugh L Callendar and the formula obtained by Max Planck using quantization of energy. We use R and Maxima to analyze their fitness on coordinating experimental data and indicate some limitations with experiments in this area.

Biophysics In Applications, Marilyn R. Gunner

Open Educational Resources

No abstract provided.

Exciton Polaritons In Two-Dimensional Transition Metal Dichalcogenides, Jie Gu

Dissertations, Theses, and Capstone Projects

Strong interaction between photons and excitons in semiconductors results in the formation of half-light half-matter quasiparticles termed exciton-polaritons. Owing to their hybrid character, they inherit the strong interparticle interaction from their excitonic (matter) component via Coulomb interaction while the photonic component lends the small mass (~10⁵ times lighter than free electrons) and long propagation distances. Additionally, exciton-polaritons also carry properties of the host material excitons such as spin and valley polarization and can be probed via the photons that leak out of the cavities since the photon carries all the information owing to conservation laws. Since the first demonstration …

Interplay Of Magnetism, Superconductivity, And Topological Phases Of Matter, Cody Youmans

Dissertations, Theses, and Capstone Projects

Multiband superconducting materials, such as iron pnictides and doped topological insulators, have shown to be particularly promising platforms for realizing unconventional electronic behavior of both fundamental and practical importance. Similarly, new innovations in the engineering of gapped topological phases, like semiconductor based Kitaev chains and topological insulator based heterostructures, have opened new directions for solid-state design. Central to much of the excitement generated by such multifaceted electronic systems is a rich interplay between various inherent structural ordering tendencies and topologically non-trivial properties.

In some classes of pnictides, spin density wave order coexists with superconductivity over a range of doping and …

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

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 …

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

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 the …

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

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 …

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

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; …

Stability And Application Of The K-Core Dynamical Model To Biological Networks, Francesca Beatrice Arese Lucini

Dissertations, Theses, and Capstone Projects

The objective of the dissertation is to illustrate the importance of the k-core dynamical model, by first presenting the stability analysis of the nonlinear k-core model and compare its solution to the most widely used linear model. Second, I show a real world application of the k-core model to describe properties of neural networks, specifically, the transition from conscious to subliminal perception.

On Different Parametrizations Of Feynman Integrals, Ray Daniel Sameshima

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 …

Physics And Mathematics Of Graded Quivers, Azeem Hasan

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 …

Yields Of Weakly Bound Light Nuclei As A Probe Of The Statistical Hadronization Model, Yiming Cai, Thomas D. Cohen, Boris A. Gelman, Yukari Yamauchi

Publications and Research

The statistical hadronization model successfully describes the yields of hadrons and light nuclei from central heavy-ion collisions over a wide range of energies. It is a simple and efficient phenomenological framework in which the relative yields for very high energy collisions are essentially determined by a single model parameter—the chemical freeze-out temperature. Recent measurements of yields of hadrons and light nuclei covering over nine orders of magnitudes from the ALICE collaboration at the Large Hadron Collider were described by the model with remarkable accuracy with a chemical freeze-out temperature of 156.5 ± 1.5 MeV. A key physical question is whether …

Master Integrals For The Two-Loop, Non-Planar Qcd Corrections To Top-Quark Pair Production In The Quark-Annihilation Channel, Matteo Becchetti, Roberto Bonciani, Valerio Casconi, Andrea Ferroglia, Simone Lavacca, Andreas Von Manteuffel

Publications and Research

We present the analytic calculation of the Master Integrals for the two-loop, non-planar topologies that enter the calculation of the amplitude for top-quark pair hadroproduction in the quark-annihilation channel. Using the method of differential equations, we expand the integrals in powers of the dimensional regulator ε and determine the expansion coefficients in terms of generalized harmonic polylogarithms of two dimensionless variables through to weight four.

Optimization Of Information Storage With Quantum Walks, Gui Zhen Lu

Theses and Dissertations

A four-vertex quantum graph was analyzed with the objective of storing the highest ampli- tude of an incoming qubit. The procedure included the use of phase shifters to allow the user to store and release information when he or she chooses. Several parameters, such as the phase shift, location of the phase shifter, the size and shape of the binding graph and initial incoming state were varied independently to optimize the storage capacity of the graph.

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

Theses and Dissertations

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. …

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 …

Optical Detection And Storage Of Entanglement In Plasmonically Coupled Quantum-Dot Qubits, M. Otten, S.K. Gray, German Kolmakov V

Publications and Research

Recent proposals and advances in quantum simulations, quantum cryptography, and quantum communications substantially rely on quantum entanglement formation. Contrary to the conventional wisdom that dissipation destroys quantum coherence, coupling with a dissipative environment can also generate entanglement. We consider a system composed of two quantum-dot qubits coupled with a common, damped surface plasmon mode; each quantum dot is also coupled to a separate photonic cavity mode. Cavity quantum electrodynamics calculations show that upon optical excitation by a femtosecond laser pulse, entanglement of the quantum-dot excitons occurs, and the time evolution of the g(2) pair correlation function of the cavity photons …

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

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 Energy Transfer And Molecular Energetics Using Photonic Nanostructures, Rahul Deshmukh

Dissertations, Theses, and Capstone Projects

In the last three decades, the design and fabrication of different types of photonic nanostructures have allowed us to control and enhance the interaction of light (or photons) with matter (or excitons). In this work, we demonstrate the use of three different nanostructures to control different material properties. The design and fabrication of the nanostructures is discussed along with the results obtained using characterization techniques of angle-resolved white light reflectivity and transmission, and time-resolved and steady-state photoluminescence experiments. Specifically, we demonstrate the use of Optical Topological Transitions (OTT) in metamaterials to show enhanced efficiency in the non-radiative transfer of energy …

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

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 …

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

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

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 …

Using Fundamental Properties Of Light To Investigate Photonic Effects In Condensed Matter And Biological Tissues, Laura A. Sordillo

Dissertations and Theses

Light possesses characteristics such as polarization, wavelength and coherence. The interaction of light and matter, whether in a semiconductor or in a biological sample, can reveal important information about the internal properties of a system. My thesis focuses on two areas: photocarriers in gallium arsenide and biomedical optics. Varying the excitation wavelength can be used to study both biological tissue and condensed matter. I altered the excitation wavelengths to be in the longer near-infrared (NIR) optical windows, in the shortwave infrared (SWIR) range, a wavelength region previously thought to be unusable for medical imaging. With this method, I acquired high …

New Perspectives On The Schrödinger-Pauli Theory Of Electrons: Part Ii: Application To The Triplet State Of A Quantum Dot In A Magnetic Field, Marlina Slamet, Viraht Sahni

Publications and Research

The Schrödinger-Pauli (SP) theory of electrons in the presence of a static electromagnetic field can be described from the perspective of the individual electron via its equation of motion or 'Quantal Newtonian' first law. The law is in terms of 'classical' fields whose sources are quantum-mechanical expectation values of Hermitian operators taken with respect to the wave function. The law states that the sum of the external and internal fields experienced by each electron vanishes. The external field is the sum of the binding electrostatic and Lorentz fields. The internal field is the sum of fields representative of properties of …

New Perspectives On The Schrödinger-Pauli Theory Of Electrons: Part I, Viraht Sahni

Publications and Research

Schrödinger-Pauli (SP) theory is a description of electrons in the presence of a static electromagnetic field in which the interaction of the magnetic field with both the orbital and spin moments is explicitly considered. The theory is described from the new perspective of the individual electron via its equation of motion or ‘Quantal Newtonian’ first law. The law is in terms of ‘classical’ fields whose sources are quantum mechanical expectation values of Hermitian operators taken with respect to the system wave function. The law states that each electron experiences an external and an internal field, the sum of which vanish. …

Top-Quark Pair Hadroproduction In Association With A Heavy Boson At Nlo+Nnll Including Ew Corrections, Alessandro Broggio, Andrea Ferroglia, Rikkert Frederix, Davide Pagani, Benjamin D. Pecjak, Ioannis Tsinikos

Publications and Research

This work studies the associated production of a top-quark pair with a W, Z, or Higgs boson at the LHC. Predictions for the total cross sections as well as for several differential distributions of the massive particles in the final state are provided. These predictions, valid for the LHC operating at 13 TeV, include without any approximation all the NLO electroweak and QCD contributions of O(αⁱ_sα^j+1) with i + j = 2, 3. In addition, the predictions presented here improve upon the NLO QCD results by adding the effects of soft gluon emission …

Measuring The Weizsäcker-Williams Distribution Of Linearly Polarized Gluons At An Electron-Ion Collider Through Dijet Azimuthal Asymmetries, Adrian Dumitru, Vladimir Skokov, Thomas Ullrich

Publications and Research

The production of a hard dijet with small transverse momentum imbalance in semi-inclusive DIS probes the conventional and linearly polarized Weizsäcker-Williams (WW) transverse momentum dependent (TMD) gluon distributions. The latter, in particular, gives rise to an azimuthal dependence of the dijet cross section. In this paper we analyze the feasibility of a measurement of these TMDs through dijet production in DIS on a nucleus at an electron-ion collider. We introduce the MCDIJET Monte Carlo generator to sample quark-antiquark dijet configurations based on leading-order parton level cross sections with WW gluon distributions that solve the nonlinear small-x QCD evolution equations. …

Microfluidic Study Of Gravity-Driven Drainage And Coalescence Of Aqueous Two Dimensional Foams, Justin D. Heftel

Dissertations and Theses

Foams, a two-phase dispersion, are staples of the cosmetic, personal care, petroleum, pharmaceutical, and other industries. Central to these applications is the stability of the dispersion against separation. Foams break down by two mechanisms: the first is bubble coalescence, which is driven by the gravity drainage of the continuous phase. The drainage acts to push the bubbles against each other, and leads to the formation of thin lamellae, which break and cause the coalescence. The second is the mass transfer of the dispersed phase through the continuous phase, which is caused by the difference in pressures between the bubbles and …