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Articles 1 - 30 of 35
Full-Text Articles in Physical Sciences and Mathematics
Driven Dipolariton Transistors In Y-Shaped Channels, Patrick Serafin, Tim Byrnes, German Kolmakov V
Driven Dipolariton Transistors In Y-Shaped Channels, Patrick Serafin, Tim Byrnes, German Kolmakov V
Publications and Research
Exciton-dipolaritons are investigated as a platform for realizing working elements of a polaritronic transistor. Exciton-dipolaritons are three-way superposition of cavity photons, direct and indirect excitons in a bilayer semiconducting system embedded in an optical microcavity. Using the forced diffusion equation for dipolaritons, we study the room-temperature dynamics of dipolaritons in a transition-metal dichalcogenide (TMD) heterogeneous bilayer. Specifically, we considered a MoSe2-WS2 heterostructure, where a Y-shaped channel guiding the dipolariton propagation is produced. We demonstrate that polaritronic signals can be redistributed in the channels by applying a driving voltage in an optimal direction. Our findings open a route …
Schrödinger-Pauli Theory Of Electrons: New Perspectives, Viraht Sahni
Schrödinger-Pauli Theory Of Electrons: New Perspectives, Viraht Sahni
Publications and Research
The Schrödinger-Pauli (SP) theory of electrons in an electromagnetic field explicitly accounts for the electron spin moment. The many-electron theory is complemented via a new descriptive perspective viz. that 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. The external field is the sum of the binding electrostatic and a Lorentz …
Resummation Of Non-Global Logarithms In Cross Sections With Massive Particles, Marcel Balsiger, Thomas Becher, Andrea Ferroglia
Resummation Of Non-Global Logarithms In Cross Sections With Massive Particles, Marcel Balsiger, Thomas Becher, Andrea Ferroglia
Publications and Research
A factorization formalism for jet processes involving massive colored particles such as the top quark is developed, extending earlier results for the massless case. The factorization of soft emissions from the underlying hard process is implemented in an effec tive field theory framework, which forms the basis for the resummation of large logarithms. The renormalization group evolution giving rise to non-global logarithms is implemented into a parton shower code in the large-Nc limit. After a comparison of the massive and massless radiation patterns, the cross section for t¯ t production with a veto on additional central jet activity is computed, …
Control Of Molecular Energetics And Transport Via Strong Light-Matter Interaction, Rong Wu
Control Of Molecular Energetics And Transport Via Strong Light-Matter Interaction, Rong Wu
Dissertations, Theses, and Capstone Projects
Strong light-matter coupling in excitonic systems results in the formation of half-light half-matter quasiparticles called exciton polaritons. These hybrid quasiparticles take on the best of both systems, namely, the long-range propagation and coherence arising from the photonic component and the nonlinear interaction from the excitonic component. We develop methods for making high quality factor cavities and investigate the potential applications of these strongly coupled states arising specifically in organic molecular systems.
In the first project we investigate the potential of organic dye molecules to undergo condensation in an optical cavity at room temperature. The second study involves the use of …
An Accurate Solution Of The Self-Similar Orbit-Averaged Fokker-Planck Equation For Core-Collapsing Isotropic Globular Clusters: Properties And Application, Yuta Ito
Dissertations, Theses, and Capstone Projects
Hundreds of dense star clusters exist in almost all galaxies. Each cluster is composed of approximately ten thousand through ten million stars. The stars orbit in the clusters due to the clusters' self-gravity. Standard stellar dynamics expects that the clusters behave like collisionless self-gravitating systems on short time scales (~ million years) and the stars travel in smooth continuous orbits. Such clusters temporally settle to dynamically stable states or quasi-stationary states (QSS). Two fundamental QSS models are the isothermal- and polytropic- spheres since they have similar structures to the actual core (central part) and halo (outskirt) of the clusters. The …
Particle Dynamics In Anti-De Sitter Space By Eih Method, Jiusi Lei
Particle Dynamics In Anti-De Sitter Space By Eih Method, Jiusi Lei
Dissertations, Theses, and Capstone Projects
Following the work of Einstein, Infeld and Hoffmann, we show that particle dynamics in Anti-de Sitter spacetime can be built up by regarding singularities in spacetime manifold as the source of particles.
Since gauge fields play a foundational role in the action, the singularities are chosen to be point-like instantons. Their winding number, defined by an integration on the spheres surrounding those singularities, will turn out to be related to their masses. And their action, derived from the Chern-Simons forms, will be a co-adjoint orbit action, with group element g ∈ SO(4, 2) describing the collective coordinates of the particle. …
Wave Propagation In Random And Topological Media, Yuhao Kang
Wave Propagation In Random And Topological Media, Yuhao Kang
Dissertations, Theses, and Capstone Projects
This thesis discusses wave propagation in two kinds of systems, random media and topological insulators. In a disordered system, the wave is randomized by multiple scattering. The scattering matrix and associated delay times are powerful tools with which to describe wave transport. We discuss the relation among the Wigner time, the transmission time, and energy density in a lossless or lossy system. We propose the zeros of the transmission matrix and show how to manipulate the zero-transmission mode in a nonunitary system. In a photonic topological insulator, we realize an edge mode and discuss its robustness in the face of …
Emulating Condensed Matter Systems In Classical Wave Metamaterials, Matthew Weiner
Emulating Condensed Matter Systems In Classical Wave Metamaterials, Matthew Weiner
Dissertations, Theses, and Capstone Projects
One of the best tools we have for the edification of physics is the analogy. When we take our classical set of states and dynamical variables in phase space and treat them as vectors and Hermitian operators respectively in Hilbert space through the canonical quantization, we lose out on a lot of the intuition developed with the previous classical physics. With classical physics, through our own experiences and understanding of how systems should behave, we create easy-to-understand analogies: we compare the Bohr model of the atom to the motion of the planets, we compare electrical circuits to the flow of …
Linear And Non-Linear Elastic Constants Of Crystalline Materials From First-Principles Calculations, David Cuffari
Linear And Non-Linear Elastic Constants Of Crystalline Materials From First-Principles Calculations, David Cuffari
Dissertations, Theses, and Capstone Projects
Novel methods based on the use of density functional theory (DFT) calculations are developed and applied to calculate linear and non-linear elastic constants of materials at zero and finite temperature. These methods rely on finite difference techniques and are designed to be general, numerically accurate, and suitable to investigate the thermoelastic properties of anharmonic materials. A first method was developed to compute the third-order elastic constants of crystalline materials at zero temperature, a task that is numerically challenging and is currently undertaken by using approaches typically applicable to cubic and hexagonal crystalline systems. This method relies on numerical differentiation of …
Snow-Albedo Feedback In Northern Alaska: How Vegetation Influences Snowmelt, Lucas C. Reckhaus
Snow-Albedo Feedback In Northern Alaska: How Vegetation Influences Snowmelt, Lucas C. Reckhaus
Theses and Dissertations
This paper investigates how the snow-albedo feedback mechanism of the arctic is changing in response to rising climate temperatures. Specifically, the interplay of vegetation and snowmelt, and how these two variables can be correlated. This has the potential to refine climate modelling of the spring transition season. Research was conducted at the ecoregion scale in northern Alaska from 2000 to 2020. Each ecoregion is defined by distinct topographic and ecological conditions, allowing for meaningful contrast between the patterns of spring albedo transition across surface conditions and vegetation types. The five most northerly ecoregions of Alaska are chosen as they encompass …
Qwasi: The Quantum Walk Simulator, Warren V. Wilson
Qwasi: The Quantum Walk Simulator, Warren V. Wilson
Theses and Dissertations
As quantum computing continues to evolve, the ability to design and analyze novel quantum algorithms becomes a necessary focus for research. In many instances, the virtues of quantum algorithms only become evident when compared to their classical counterparts, so a study of the former often begins with a consideration of the latter. This is very much the case with quantum walk algorithms, as the success of random walks and their many, varied applications have inspired much interest in quantum correlates. Unfortunately, finding purely algebraic solutions for quantum walks is an elusive endeavor. At best, and when solvable, they require simple …
Evolutionary Algorithms Converge Towards Evolved Biological Photonic Structures, Mamadou Aliou Barry, Vincent Berthier, Bobo D. Wilts, Marie-Claire Cambourieux, Pauline Bennet, Rémi Pollès, Olivier Teytaud, Emmanuel Centeno, Nicolas Biais, Antoine Moreau
Evolutionary Algorithms Converge Towards Evolved Biological Photonic Structures, Mamadou Aliou Barry, Vincent Berthier, Bobo D. Wilts, Marie-Claire Cambourieux, Pauline Bennet, Rémi Pollès, Olivier Teytaud, Emmanuel Centeno, Nicolas Biais, Antoine Moreau
Publications and Research
Nature features a plethora of extraordinary photonic architectures that have been optimized through natural evolution in order to more efciently refect, absorb or scatter light. While numerical optimization is increasingly and successfully used in photonics, it has yet to replicate any of these complex naturally occurring structures. Using evolutionary algorithms inspired by natural evolution and performing particular optimizations (maximize refection for a given wavelength, for a broad range of wavelength or maximize the scattering of light), we have retrieved the most stereotypical natural photonic structures. Whether those structures are Bragg mirrors, chirped dielectric mirrors or the gratings on top of …
Circuits With Broken Fibration Symmetries Perform Core Logic Computations In Biological Networks, Ian Leifer, Flaviano Morone, Saulo D. S. Reis, José S. Andrade Jr., Mariano Sigman, Hernán A. Makse
Circuits With Broken Fibration Symmetries Perform Core Logic Computations In Biological Networks, Ian Leifer, Flaviano Morone, Saulo D. S. Reis, José S. Andrade Jr., Mariano Sigman, Hernán A. Makse
Publications and Research
We show that logic computational circuits in gene regulatory networks arise from a fibration symmetry breaking in the network structure. From this idea we implement a constructive procedure that reveals a hierarchy of genetic circuits, ubiquitous across species, that are surprising analogues to the emblematic circuits of solid-state electronics: starting from the transistor and progressing to ring oscillators, current-mirror circuits to toggle switches and flip-flops. These canonical variants serve fundamental operations of synchronization and clocks (in their symmetric states) and memory storage (in their broken symmetry states). These conclusions introduce a theoretically principled strategy to search for computational building blocks …
Fabrication Of Magnetocaloric La(Fe,Si)13 Thick Films, N H. Dung, N B. Doan, P De Rango, L Ranno, Karl G. Sandeman, N M. Dempsey
Fabrication Of Magnetocaloric La(Fe,Si)13 Thick Films, N H. Dung, N B. Doan, P De Rango, L Ranno, Karl G. Sandeman, N M. Dempsey
Publications and Research
La(Fe,Si)13–based compounds are considered to be very promising magnetocaloric materials for magnetic refrigeration applications. Many studies have focused on this material family but only in bulk form. In this paper we report on the fabrication of thick films of La(Fe,Si)13, both with and without post-hydriding. These films exhibit magnetic and structural properties comparable to bulk materials. We also observe that the ferromagnetic phase transition has a negative thermal hysteresis, a phenomenon not previously found in this material but which may have its origins in the availability of a strain energy reservoir, as in the cases of …
At The Interface Of Algebra And Statistics, Tai-Danae Bradley
At The Interface Of Algebra And Statistics, Tai-Danae Bradley
Dissertations, Theses, and Capstone Projects
This thesis takes inspiration from quantum physics to investigate mathematical structure that lies at the interface of algebra and statistics. The starting point is a passage from classical probability theory to quantum probability theory. The quantum version of a probability distribution is a density operator, the quantum version of marginalizing is an operation called the partial trace, and the quantum version of a marginal probability distribution is a reduced density operator. Every joint probability distribution on a finite set can be modeled as a rank one density operator. By applying the partial trace, we obtain reduced density operators whose diagonals …
Proton Pumping Mechanism In Cytochrome C Oxidase, Xiuhong Cai
Proton Pumping Mechanism In Cytochrome C Oxidase, Xiuhong Cai
Dissertations, Theses, and Capstone Projects
Cytochrome c Oxidase (CcO), is the terminal electron acceptor in the membrane bound aerobic respiratory chain. It reduces O2 to water. The energy released by this reaction is stored by pumping protons from the high pH, N-side of the membrane to the low pH, P-side. The generated proton gradient provides the motive force for synthesis of ATP by the ATP synthase.
Building a proton gradient across the membrane requires that proton transport must occur along controllable proton pathways to prevent proton leakage to the N-side. It has been suggested that CcO function requires proton transfer channels in both the …
Small-X Qcd Calculations With A Biased Ensemble, Gary Kapilevich
Small-X Qcd Calculations With A Biased Ensemble, Gary Kapilevich
Dissertations, Theses, and Capstone Projects
In this dissertation, I will argue that we can study functional fluctuations in unintegrated gluon distributions, in the MV model as well as JIMWLK, using reweighting techniques, which will allow me to calculate QCD observables with "biased ensembles". This technique will enable me to study rare functional configurations of the gluon distributions, that might have been selected for in, for example, the centrality criteria used by the ATLAS and ALICE collaborations. After a review of these techniques, as well as a review of QCD physics at high energy in general, I will use biased ensembles to compute observables in two …
Generating Entanglement With The Dynamical Lamb Effect, Mirko Amico
Generating Entanglement With The Dynamical Lamb Effect, Mirko Amico
Dissertations, Theses, and Capstone Projects
According to quantum field theory, the vacuum is filled with virtual particles which can be turned into real ones under the influence of external perturbations. Phenomena of this kind are commonly referred to as quantum vacuum phenomena. Several quantum vacuum phenomena related to the peculiar nature of the quantum vacuum have been predicted, some of which, such as the Lamb shift and the Casimir effect, have been experimentally found. Other examples of quantum vacuum phenomena include the Unruh effect, the dynamical Casimir effect and the dynamical Lamb effect. The dynamical Lamb effect was first predicted by considering the situation of …
Generalized Four-Dimensional Effective Hadronic Supersymmetry Based On Quantum Chromodynamics (Qcd), Enxi Yu
Generalized Four-Dimensional Effective Hadronic Supersymmetry Based On Quantum Chromodynamics (Qcd), Enxi Yu
Dissertations, Theses, and Capstone Projects
New discovery in multiple laboratories around the globe has shown a supersymmetry between hadrons—baryons and mesons. In order to generalize the phenomenological hadronic supersymmetry, the spin-flavor SU(6) symmetry need an extension. This thesis present how we can extend SU(6) symmetry so that hadronic supersymmetry can be included. In the future, this extension can be also applied to pentaquark and tetraquark bags, for which there is an ongoing research in laboratories.
Optically Pumped Spin Polarization As A Probe Of Many-Body Thermalization, Daniela Pagliero, Pablo R. Zangara, Jacob Henshaw, Ashok Ajoy, Rodolfo H. Acosta, Jeffrey A. Reimer, Alexander Pines, Carlos A. Meriles
Optically Pumped Spin Polarization As A Probe Of Many-Body Thermalization, Daniela Pagliero, Pablo R. Zangara, Jacob Henshaw, Ashok Ajoy, Rodolfo H. Acosta, Jeffrey A. Reimer, Alexander Pines, Carlos A. Meriles
Publications and Research
Disorder and many body interactions are known to impact transport and thermalization in competing ways, with the dominance of one or the other giving rise to fundamentally different dynamical phases. Here we investigate the spin diffusion dynamics of 13C in diamond, which we dynamically polarize at room temperature via optical spin pumping of engineered color centers. We focus on low-abundance, strongly hyperfine-coupled nuclei, whose role in the polarization transport we expose through the integrated impact of variable radio-frequency excitation on the observable bulk 13C magnetic resonance signal. Unexpectedly, we find good thermal contact throughout the nuclear spin bath, …
Fibration Symmetries Uncover The Building Blocks Of Biological Networks, Flaviano Morone, Ian Leifer, Hernán A. Makse
Fibration Symmetries Uncover The Building Blocks Of Biological Networks, Flaviano Morone, Ian Leifer, Hernán A. Makse
Publications and Research
A major ambition of systems science is to uncover the building blocks of any biological network to decipher how cellular function emerges from their interactions. Here, we introduce a graph representation of the information flow in these networks as a set of input trees, one for each node, which contains all pathways along which information can be transmitted in the network. In this representation, we find remarkable symmetries in the input trees that deconstruct the network into functional building blocks called fibers. Nodes in a fiber have isomorphic input trees and thus process equivalent dynamics and synchronize their activity. Each …
Microfluidic Study Of The Electrocoalescence Of Aqueous Droplets In Crude Oil, Thomas Leary, Mohsen Yeganeh, Charles Maldarelli
Microfluidic Study Of The Electrocoalescence Of Aqueous Droplets In Crude Oil, Thomas Leary, Mohsen Yeganeh, Charles Maldarelli
Publications and Research
In electrocoalescence, an electric field is applied to a dispersion of conducting water droplets in a poorly conducting oil to force the droplets to merge in the direction of the field. Electrocoalescence is used in petroleum refining to separate water from crude oil and in droplet-based microfluidics to combine droplets of water in oil and to break emulsions. Using a microfluidic design to generate a two-dimensional (2D) emulsion, we demonstrate that electrocoalescence in an opaque crude oil can be visualized with optical microscopy and studied on an individual droplet basis in a chamber whose height is small enough to make …
Syllabus Ee330 Electromagnetics, Nicholas Madamopoulos
Syllabus Ee330 Electromagnetics, Nicholas Madamopoulos
Open Educational Resources
Concepts covered in the undergraduate electrical engineering class of electromagnetics
Density Functional Theory Study Of Two-Dimensional Boron Nitride Films, Pradip R. Niraula
Density Functional Theory Study Of Two-Dimensional Boron Nitride Films, Pradip R. Niraula
Dissertations, Theses, and Capstone Projects
Since graphene was isolated in 2004, the number of two-dimensional (2D) materials and their scientific relevance have grown exponentially. Besides graphene, one of the most important and technolocially promizing 2D materials that has emerged in recent years is hexagonal boron nitride, in its monolayer or multilayer form. In my thesis work, I used density functional theory (DFT) calculations to investigate the properties of boron nitride films. In particular, I first studied the properties (i.e. formation energy, defect states, and structure) of point charged defects in monolayer and bilayer hexagonal boron nitride, and subsequently, I focused on the linear and nonlinear …
Computational Modeling Of Charge And Excitation Energy Transfer Dynamics In Complex Environments, Ning Chen
Computational Modeling Of Charge And Excitation Energy Transfer Dynamics In Complex Environments, Ning Chen
Dissertations, Theses, and Capstone Projects
This thesis describes computational simulations of charge and exciton dynamics and quantum calculations of organic conjugated oligomers. A comprehensive computational study of charge hopping dynamics was conducted for a model of disordered chain of sites coupled to quantum environments. Time-dependent mean square displacement, diffusion constant, and mobility were calculated by three different computational methods for solving the master equation, which validate the accuracy of calculations. Approximate rate kernels were also tested to understand the effects of approximations in representing quantum environments. In addition to the effects of temperature and disorder, different values of the gradient in the site energy were …
Duality In A Model Of Layered Superfluids And Sliding Phases, Steven Vayl
Duality In A Model Of Layered Superfluids And Sliding Phases, Steven Vayl
Dissertations, Theses, and Capstone Projects
The intent of my project is to determine if the proposal of sliding phases in XY layered systems has physical ground. It will be done by comparing numerical and analytical results for a layered XY models. Sliding phases were first proposed in the context of DNA complexes and then extended to XY models, 1D coupled wires and superfluid films. The existence of the sliding phase would mean that there is a phase transition from 3D to 2D behavior. Such systems have been studied both in the clean case and with disorder. The idea of the sliding phases is based on …
Ii-Vi Type-Ii Quantum Dot Superlattices For Novel Applications, Vasilios Deligiannakis
Ii-Vi Type-Ii Quantum Dot Superlattices For Novel Applications, Vasilios Deligiannakis
Dissertations, Theses, and Capstone Projects
In this thesis, we discuss the growth procedure and the characterization results obtained for epitaxially grown submonolayer type-II quantum dot superlattices made of II-VI semiconductors. We have investigated the spin dynamics of ZnSe layers with embedded type-II ZnTe quantum dots and the use of (Zn)CdTe/ZnCdSe QDs for intermediate band solar cell (IBSC). Samples with a higher quantum dot density exhibit longer electron spin lifetimes, up to ~1 ns at low temperatures. Tellurium isoelectronic centers, which form in the ZnSe spacer regions as a result of the growth conditions, were also probed. A new growth sequence for type-II (Zn)CdTe/ZnCdSe (QDs) was …
Effect Of Direct-Current Magnetic Field On The Specific Absorption Rate Of Metamagnetic Comnsi: A Potential Approach To Switchable Hyperthermia Therapy, K C. Ugochukwu, M M. Sadiq, E S. Biegel, L Meagher, M R. Hill, Karl G. Sandeman, A Haydon, K Suzuki
Effect Of Direct-Current Magnetic Field On The Specific Absorption Rate Of Metamagnetic Comnsi: A Potential Approach To Switchable Hyperthermia Therapy, K C. Ugochukwu, M M. Sadiq, E S. Biegel, L Meagher, M R. Hill, Karl G. Sandeman, A Haydon, K Suzuki
Publications and Research
Materials with 1st order antiferromagnetic (AFM) to high-magnetization (MM) phase transition known for their inverse magnetocaloric effect, abrupt rise in magnetization and magnetoelastic coupling, are promising for application in combined simultaneous diagnosis and targeted cancer therapy. A therapy that combines alternating-current (ac) and direct-current (dc) magnetic fields for simultaneous magnetic hyperthermia therapy (MHT) and magnetic resonance imaging (MRI), using same magnetic particles for heating and as con- trast agents. We report a proof-of-concept study on the induction heating ability of 1st order metamagnetic material with moderate specific absorption rates (SAR) and no tendency for agglomeration, for potential MHT and MRI …
Universal Gravitation And Circular Motion, Xin Gao
Universal Gravitation And Circular Motion, Xin Gao
Open Educational Resources
This is designed to serve as a pre-lab. Students will be asked to watch videos linked to in the instructions before the lecture and complete a worksheet with thought- provoking questions guiding them to relating circular motion with the motion of a satellite or planet, and then think about what force is serving as the centripetal force for planets when they move around the sun. Students will also be prompted to think about whether or not there is really no gravity in space, so as to realize how misleading those terms, such as “weightless” or “zero gravity in space” are.
Double Inclusive Small-X Gluon Production And Their Azimuthal Correlations In A Biased Ensemble, Gary Kapilevich
Double Inclusive Small-X Gluon Production And Their Azimuthal Correlations In A Biased Ensemble, Gary Kapilevich
Publications and Research
We consider double gg → g production in the presence of a bias on the unintegrated gluon distribution of the colliding hadrons or nuclei. Such bias could be due to the selection of configurations with a greater number of gluons or higher mean transverse momentum squared or, more generally, due to a modified spectral shape of the gluon distribution in the hadrons. Hence, we consider reweighted functional averages over the stochastic ensemble of small-x gluons. We evaluate explicitly the double inclusive gluon transverse momentum spectrum in high-energy collisions, and their azimuthal correlations, for a few simple examples of biases.