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Articles 1 - 30 of 112
Full-Text Articles in Physical Sciences and Mathematics
Probability Distributions Of The Scalar Potential, Candace Mathews
Probability Distributions Of The Scalar Potential, Candace Mathews
Legacy Theses & Dissertations (2009 - 2024)
In the study of cosmological inflation, string theory and supersymmetry have motivated a wide range of possible inflationary models. These models can be parameterized by a scalar potential V, which is a function of N scalar fields, and determines cosmological parameters such as the vacuum stability and energy density. In principle, we can determine V through high energy physics, such as string theory. In practice, though we may not know the details of V we might have clues about a distribution of plausible V’s, which we can build statistics on to further analyze. The purpose of this thesis defense is …
Turning Density Functional Theory Calculations Into Molecular Mechanics Simulations : Establishing The Fluctuating Density Model For Rna Nucleobases, Christopher A. Myers
Turning Density Functional Theory Calculations Into Molecular Mechanics Simulations : Establishing The Fluctuating Density Model For Rna Nucleobases, Christopher A. Myers
Legacy Theses & Dissertations (2009 - 2024)
Molecular mechanics (MD) simulations and density functional theory (DFT) have been the backbone of computational chemistry for decades. Due to its accuracy and computational feasibility, DFT has become the go-to method for theoretically predicting interaction energies, polarizability, and other electronic properties of small molecules at the quantum mechanical level. Although less fundamental than DFT, molecular mechanics (MM) algorithms have been just as influential in the fields of biology and chemistry, owing their success to the ability to compute measurable, macroscopic quantities for systems with tens of thousands to hundreds of thousands of atoms at a time. Nevertheless, MD simulations would …
Calculational Methods In Conformal Field Theory, Thomas Andrew Vandermeulen
Calculational Methods In Conformal Field Theory, Thomas Andrew Vandermeulen
Legacy Theses & Dissertations (2009 - 2024)
We examine conformal field theories and their gaugings (orbifolds), first on the torus and then on surfaces of higher genus. Specific attention is paid to performing explicit calculations, to which end we introduce a number of specialized formalisms. Namely, the technology of flavored partition functions allows for a general treatment of orbifolds in theories with conserved currents, and Arakelov geometry facilitates the derivation of novel expressions for geometric quantities appearing commonly on higher genus worldsheets. Ultimately, we leverage the resulting expressions in the calculation of correlation functions via degeneration of Riemann surfaces.
Computational Methods For Propagation Of Optical Fields With The Angle-Impact Wigner Function, Jeremy Wittkopp
Computational Methods For Propagation Of Optical Fields With The Angle-Impact Wigner Function, Jeremy Wittkopp
Legacy Theses & Dissertations (2009 - 2024)
In designing an optical setup for an experiment, one usually turns to simulations first in order to model the propagation of light through the proposed system. This way, the experimenter can determine if the system is operating as intended. In order for these simulations to be useful, they need to properly describe the propagation of light. In order to simplify calculations, most contemporary software makes assumptions on the nature of the light being propagated. Specifically, simulations typically consider optical fields that are beam-like (i.e., most of the rays comprising the field deviate only slightly in angle from the beam's primary …
An Entropic Approach To Dynamics, Pedro Henrique Moreira Pessoa
An Entropic Approach To Dynamics, Pedro Henrique Moreira Pessoa
Legacy Theses & Dissertations (2009 - 2024)
The present thesis deals with different aspects of probability, the method of maximum entropy, information geometry, and dynamical systems and their applications to statistical physics and complex systems. Those topics come together in the framework for dynamics termed entropic dynamics. Work on the topic was initiated by my PhD advisor Professor Ariel Caticha and many colleagues at University at Albany as a method for explaining the dynamical processes in quantum mechanics from first principles of probability theory.
Signal Yields And Detector Modeling In Xenon Time Projection Chambers, And Results Of An Effective Field Theory Dark Matter Search Using Lux Data, Gregory Ransford Carl Rischbieter
Signal Yields And Detector Modeling In Xenon Time Projection Chambers, And Results Of An Effective Field Theory Dark Matter Search Using Lux Data, Gregory Ransford Carl Rischbieter
Legacy Theses & Dissertations (2009 - 2024)
The nature of dark matter continues to be one of the biggest remaining mysteries in physics. Astrophysical measurements indicate that dark matter makes up more than a quarter of the Universe's total energy density, and it is well-motivated that dark matter is comprised of Weakly Interacting Massive Particles (WIMPs). Direct detection techniques utilizing liquid and gaseous noble elements have become the primary method of probing the potential non-gravitational interactions between WIMPs and Standard Model matter, with the leading technology being the dual-phase Time Projection Chamber (TPC). The Large Underground Xenon (LUX) and its second-generation successor, LUX-ZEPLIN (LZ), are two xenon …
X Ray Phase And Coherent Scatter Imaging Measurements, Pikting Cheung
X Ray Phase And Coherent Scatter Imaging Measurements, Pikting Cheung
Legacy Theses & Dissertations (2009 - 2024)
Traditional x-ray images are good for distinguishing between materials with very different absorption coefficients. However, detecting breast cancer using conventional x-ray imaging is hard because cancer tissue has similar absorption coefficients as normal tissue. Annually 43,600 women will die from breast cancer. The odds of survival are better if the cancer is diagnosed at an early stage, but mammography tends to have high rates of missed cancers. Mammography also tends to have a high false-positive rate, which leads to unnecessary biopsies. Two techniques with potential to add additional information to breast imaging have been investigated. X-ray phase imaging has been …
A Novel Phase And Spectroscopic Imaging Technique To Evaluate Cellular Functions, Ting Chean Khoo
A Novel Phase And Spectroscopic Imaging Technique To Evaluate Cellular Functions, Ting Chean Khoo
Legacy Theses & Dissertations (2009 - 2024)
This thesis presents the application of Raman spectroscopy, digital holographic microscope (DHM) and transport intensity equation (TIE) in imaging biological samples. Raman spectroscopy is a non-destructive technique that can provide chemical structure, concentration, temperature, and molecular interactions. On the other hand, DHM and TIE provide physical measurements such as height, width, area and volume.We applied Raman spectroscopy to study iron-bound transferrin (Tf) in intact human breast cancer cells. Iron is an essential element required for human life and is highly regulated in the body. As the exact mechanisms of iron-bound Tf in cells are not well known, we developed a …
X Ray Phase And Coherent Scatter Imaging Measurements, Mahboob Ur Rehman
X Ray Phase And Coherent Scatter Imaging Measurements, Mahboob Ur Rehman
Legacy Theses & Dissertations (2009 - 2024)
In conventional radiography, anatomical information of the patients can be obtained, distinguishing different tissue types, e.g. bone and soft tissue. However, it is difficult to obtain appreciable contrast between two different types of soft tissues. Instead, coherent x-ray scattering can be utilized to obtain images which can differentiate between normal and cancerous cells of breast. An x-ray system using a conventional source and simple slot apertures was tested. Materials with scatter signatures that mimic breast cancer were buried in layers of fat of increasing thickness and imaged. The result showed that the contrast and signal to noise ratio (SNR) remained …
System Measurements For X-Ray Phase And Diffraction Imaging, Erik Wolfgang Tripi
System Measurements For X-Ray Phase And Diffraction Imaging, Erik Wolfgang Tripi
Legacy Theses & Dissertations (2009 - 2024)
In medical imaging, X rays are used to look inside the body to find fractures in bones, abnormal masses, cavities in teeth, and so on. What makes X rays so good at looking at these types of structures is the X ray’s penetration power. When imaging soft tissue to search for tumors, X-ray images tend to have difficulty performing well. The reason for this is that the background structures, such as fat or fibro glandular tissue have similar absorption coefficients as the tumor. Mammography tends to have a high false positive rate and can miss tumors entirely as well. There …
Reliability Characterization Of A Low-K Dielectric Using Its Magnetoresistance As A Diagnostic Tool, Philip Alister Williams
Reliability Characterization Of A Low-K Dielectric Using Its Magnetoresistance As A Diagnostic Tool, Philip Alister Williams
Legacy Theses & Dissertations (2009 - 2024)
The introduction of low dielectric constant materials within the integrated circuit (IC) chip technology industry was a concerted effort to decrease the resistance-capacitance (RC) time delay inherent within the dielectric materials used as insulators. This stems from a demand for greater device density per IC chip and decreased feature sizes but is fast becoming a reliability issue. Concomitant with the demand for decreased feature sizes, also in adherence with Moore’s Law (which states that the number of devices on a die doubles every two years), is a reduction in device speed and performance due to device intra-level interconnection signal delays. …
Entropic Density Functional Theory : Entropic Inference And The Equilibrium State Of Inhomogeneous Fluids, Ahmad Yousefi
Entropic Density Functional Theory : Entropic Inference And The Equilibrium State Of Inhomogeneous Fluids, Ahmad Yousefi
Legacy Theses & Dissertations (2009 - 2024)
A unified formulation of the density functional theory is constructed on the foundations of entropic inference in both the classical and the quantum regimes. The theory is introduced as an application of entropic inference for inhomogeneous fluids in thermal equilibrium. It is shown that entropic inference reproduces the variational principle of DFT when informationabout expected density of particles is imposed. In the classical regime, this process introduces a family of trial density-parametrized probability distributions, and consequently a trial entropy, from which the preferred one is found using the method of Maximum Entropy (MaxEnt). In the quantum regime, similarly, the process …
Image Data Analysis And Design Optimization Of The Snowball Chamber, Yujia Huang
Image Data Analysis And Design Optimization Of The Snowball Chamber, Yujia Huang
Legacy Theses & Dissertations (2009 - 2024)
Dark Matter is the invisible massive particle that makes up over 26.8 percent of the mass-energy content of the universe. Weakly Interacting Massive Particles, or WIMPs, are one of the candidates of dark matter particles. Many scientists around the world are trying to figure out how to detect detect dark matter using either indirect search, direct production or direct detection experiments. However, due to the lack of evidence of finding WIMPs in direct detection experiments at a large mass scale, a call for investigating WIMPs at a lower mass range is attracting more attention.
The Foundations Of Inference And Its Application To Fundamental Physics, Nicholas Matthew Carrara
The Foundations Of Inference And Its Application To Fundamental Physics, Nicholas Matthew Carrara
Legacy Theses & Dissertations (2009 - 2024)
This thesis concerns the foundations of inference – probability theory,entropic inference, information geometry, etc. – and its application to the Entropic Dynamics (ED) approach to Quantum Mechanics (QM) [21, 22, 41, 53, 56–61, 150–153, 165, 195, 196, 268]. The first half of this thesis, chapters 2-6, concern the development of the inference framework. We begin in chapter 2 by discussing de- ductive inference, which involves formal logic and it’s role in access- ing the truth of propositions. We eventually discover that deductive inference is incomplete, in that it can’t address situations in which we have incomplete information. This necessitates a …
Simulation Analysis Of The Snowball Chamber, Thomas Guile
Simulation Analysis Of The Snowball Chamber, Thomas Guile
Legacy Theses & Dissertations (2009 - 2024)
Dark matter is non-baryonic, weakly interacting matter that makes up nearly 85% of the mass ofour universe, as seen through many different phenomena such as gravitational lensing and flat galactic rotation curves [48]. There are many experiments across the globe that are working to find these dark matter particles, but despite increasing levels of detector sensitivity, dark matter has been difficult to detect. Because of this, it is possible that dark matter has a lower mass than originally predicted. A new detector, the Snowball Chamber, could be used to aid in this search. By using the light molecule of water, …
Statistical And Variational Modeling And Analysis Of Passive Integrated Photonic Devices, Norbert Dinyi Agbodo
Statistical And Variational Modeling And Analysis Of Passive Integrated Photonic Devices, Norbert Dinyi Agbodo
Legacy Theses & Dissertations (2009 - 2024)
The success of Si as a platform for photonic devices and the associated availabilityof wafer-scale, ultra-high resolution lithography for Si CMOS has helped lead to the rapid advance of Si-based integrated photonics manufacturing over the past decade. This evolution is nearing the point of integration of Si-based photonics together with Si-CMOS for compact, high speed, high bandwidth, and cost-effective devices. However, due to the sensitive nature of passive and active photonic devices, variations inherent in wafer-based fabrication processes can lead to unacceptable levels of performance variation both within a give die and across a given wafer. Fully understanding the role …
The Entropic Dynamics Of Relativistic Quantum Fields In Curved Space-Time, Selman Ipek
The Entropic Dynamics Of Relativistic Quantum Fields In Curved Space-Time, Selman Ipek
Legacy Theses & Dissertations (2009 - 2024)
It has often been the case in history that the laws of physics have been used as the framework for understanding and implementing information processing. The tacit assumption is that the laws of physics are fundamental and that the notion of information is derived from these laws. Here we take the opposite view: the laws of physics are an application of the rules for processing information. The inferential framework of entropic dynamics (ED) has previously been developed by A. Caticha for the purposes of understanding and deriving quantum theory, in much the same way that E.T. Jaynes used the MaxEnt …
Therapy And Medical Imaging Applications Of Focusing Polycapillary X-Ray Optics, Weiyuan Sun
Therapy And Medical Imaging Applications Of Focusing Polycapillary X-Ray Optics, Weiyuan Sun
Legacy Theses & Dissertations (2009 - 2024)
Focusing polycapillary optics yield high gains in intensity and increased spatial resolution for a variety of clinical, lab-based, synchrotron, or in situ analysis applications. In this dissertation we investigate the extension of two applications of focusing polycapillary optics. The first is the application of polycapillary optics in radiation therapy. This discussion includes measurements and calculation of dose for focused beam orthovoltage therapy. A system has been designed to investigate whether the polycapillary optics can produce an X-ray beam which can give more accurate dose painting due to the higher dose concentration at the focal spot. X-ray exposures were measured with …
Easterly Waves Over The Eastern Pacific, Victor Manuel Torres Puente
Easterly Waves Over The Eastern Pacific, Victor Manuel Torres Puente
Legacy Theses & Dissertations (2009 - 2024)
The research in this thesis explores different processes associated with the life cycle of Easterly Waves over the tropical Eastern Pacific. These include genesis, structural evolution, intensification and a dissipating stage.
The Influence Network In 1+1 Dimensions, James Lyons Walsh
The Influence Network In 1+1 Dimensions, James Lyons Walsh
Legacy Theses & Dissertations (2009 - 2024)
The Influence Network research program [1] [2] [3] [4] starts with a very simple model
Numerical Study Of Klebanov-Tarnopolsky Models, Nathaniel Avish
Numerical Study Of Klebanov-Tarnopolsky Models, Nathaniel Avish
Legacy Theses & Dissertations (2009 - 2024)
In this thesis we perform a numerical study of the $O(N_1)\times O(N_2)\times O(N_3)$ Klebanov-Tarnopolsky (KT) model, whose large-$N$ limit is expected to admit a simple gravitational dual under the AdS/CFT correspondence. We study the $25$ special cases of the KT model which have fewer than $2^{13}$ states. For all such systems we diagonalize the Hamiltonian matrices, identify sectors which have specific charges, and compute the number of singlet states. Our findings support prior evidence that the KT model can be exactly diagonalized and therefore may have an exact analytic solution, which would be helpful in learning more about the AdS/CFT …
Measurement Of Bottom Quark Pair Production, In Association With Z Bosons And Top Quarks, With The Atlas Detector, Stewart Swift
Measurement Of Bottom Quark Pair Production, In Association With Z Bosons And Top Quarks, With The Atlas Detector, Stewart Swift
Legacy Theses & Dissertations (2009 - 2024)
This thesis uses 36.1 fb-1 of proton-proton collision data collected with the ATLAS detector situated at the Large Hadron Collider at sqrt(s) = 13 TeV to measure the associated production of Z bosons with b-quark jets. The differential cross-sections for events containing a Z boson with 1 and 2 additional b-quark-jets are measured and compared with leading and next-to-leading order theoretical predictions.
Investigation Of Optical Second Harmonic Generation From Si (100) With Process Tailored Surface & Embedded Ag Nanostructures For Advanced Si Nonlinear Nanophotonics, Gourav Bhowmik
Legacy Theses & Dissertations (2009 - 2024)
The challenge of current microelectronic architecture in transmission bandwidth and power consumption can be potentially solved by using silicon photonics technologies that are compatible with modern CMOS fabrication. One of the critical active photonic devices for Si photonics is a Si based optical modulator. Most of the reported silicon modulators rely on the free carrier plasma dispersion effect. In those cases, a weak change of the refractive index obtained by carrier accumulation, injection or depletion is utilized in a Mach-Zehnder interferometer or a microring resonator to achieve intensity modulation, rendering them difficult for chip-level implementation due to a large footprint …
Exploring Gated Nanoelectronic Devices Fabricated From 1d And 2d Materials, Prathamesh A. Dhakras
Exploring Gated Nanoelectronic Devices Fabricated From 1d And 2d Materials, Prathamesh A. Dhakras
Legacy Theses & Dissertations (2009 - 2024)
One and two dimensional materials are being extensively researched toward potential application as ultra-thin body channel materials. The difficulty of implementing physical doping methods in these materials has necessitated various alternative doping schemes, the most promising of which is the electrostatic gating technique due to its reconfigurability. This dissertation explores the different fundamental devices that can be fabricated and characterized by taking advantage of the electrostatic gating of individual single-walled carbon nanotubes (SWNTs), dense SWNT networks and exfoliated 2D tungsten diselenide (WSe2) flakes.
Electron Transport In One And Two Dimensional Materials, Samuel William Lagasse
Electron Transport In One And Two Dimensional Materials, Samuel William Lagasse
Legacy Theses & Dissertations (2009 - 2024)
This dissertation presents theoretical and experimental studies in carbon nanotubes (CNTs), graphene, and van der Waals heterostructures. The first half of the dissertation focuses on cutting edge tight-binding-based quantum transport models which are used to study proton irradiation-induced single-event effects in carbon nanotubes [1], total ionizing dose effects in graphene [2], quantum hall effect in graded graphene p-n junctions [3], and ballistic electron focusing in graphene p-n junctions [4]. In each study, tight-binding models are developed, with heavy emphasis on tying to experimental data. Once benchmarked against experiment, properties of each system which are difficult to access in the laboratory, …
Microstate Geometries & Hidden Symmetries, Qinglin Li
Microstate Geometries & Hidden Symmetries, Qinglin Li
Legacy Theses & Dissertations (2009 - 2024)
In this thesis, we study microscopic states of black holes and their hidden symmetries.
Estimation Of Planetary Photometric Emissions For Extremely Close-In Exoplanets, Jennifer L. Carter
Estimation Of Planetary Photometric Emissions For Extremely Close-In Exoplanets, Jennifer L. Carter
Legacy Theses & Dissertations (2009 - 2024)
The fine precision of photometric data available from missions like Kepler provide researchers with the ability to measure changes in light on the order of tens of parts per million (ppm). This level of precision allows researchers to measure the loss of light due to exoplanet transits as well as the light emitted by an exoplanet, or planetary photometric emissions. The planetary photometric emissions are due to the thermal emissions of the exoplanet, and reflected stellar light. In many cases it is assumed that the incident stellar light may be modeled as plane parallel rays. For extremely close-in exoplanets the …
Transits Of Non-Spherical Exoplanets, Bertrand Carado
Transits Of Non-Spherical Exoplanets, Bertrand Carado
Legacy Theses & Dissertations (2009 - 2024)
The recent years have shed light on amazing new worlds across the galaxy. It has been demonstrated that the Solar System is only one of many other systems. The Kepler Space Observatory, which was launched by NASA in 2009, has greatly contributed to expand knowledge of exoplanets whose characteristics (how massive they are, their size, orbital period, temperature...) vary on a surprisingly large scale. As an example, the least massive exoplanet known today has twice the mass of the moon [1]. The most massive exoplanet has 29 times the mass of Jupiter [2]. Orbital periods of known planets vary between …
Illumination Modulation For Improved Propagation-Based Phase Imaging, Tonmoy Chakraborty
Illumination Modulation For Improved Propagation-Based Phase Imaging, Tonmoy Chakraborty
Legacy Theses & Dissertations (2009 - 2024)
Propagation-based phase imaging enables the quantitative reconstruction of a light beam's phase from measurements of its intensity. Because the intensity depends on the time-averaged square of the field the relationship between intensity and phase is, in general, nonlinear. The transport of intensity equation (TIE), is a linear equation relating phase and propagated intensity that arises from restricting the propagation distance to be small. However, the TIE limits the spatial frequencies that can be reliably reconstructed to those below some cutoff, which limits the accuracy of reconstruction of fine features in phase. On the other hand, the low frequency components suffer …
The Entropic Dynamics Approach To The Paradigmatic Quantum Mechanical Phenomena, Susan Difranzo
The Entropic Dynamics Approach To The Paradigmatic Quantum Mechanical Phenomena, Susan Difranzo
Legacy Theses & Dissertations (2009 - 2024)
Standard Quantum Mechanics, although successful in terms of calculating and predicting