Physics Commons^™

Rigidity And Fluidity In Living And Nonliving Matter, Jorge Hernan Lopez

Dissertations - ALL

Many of the standard equilibrium statistical mechanics techniques do not readily apply to non-equilibrium phase transitions such as the fluid-to-disordered solid transition found in repulsive particulate systems. Examples of repulsive particulate systems are sand grains and colloids. The first part of this thesis contributes to methods beyond equilibrium statistical mechanics to ultimately understand the nature of the fluid-to-disordered solid transition, or jamming, from a microscopic basis.

In Chapter 2 we revisit the concept of minimal rigidity as applied to frictionless, repulsive soft sphere packings in two dimensions with the

introduction of the jamming graph. Minimal rigidity is a purely combinatorial …

The Non-Erythroid Membrane Skeleton And Its Role In Mechanotransduction, Eleni Kinfe Degaga

Dissertations - ALL

The thesis is concerned with questions regarding cellular bio-mechanics and cell surface interactions. A particular focus is thereby on the role of the spectrin membrane skeleton in transducing forces to and from non-erythroid mammalian cells. This spectrin based membrane skeleton has been the focus of much study in the context of red blood cells, as it determines their mechanical properties due to the lack of an extended actin based cytoskeleton. In stark contrast, the corresponding structure in non-erythroids is much less studied and understood, although it seems to play important roles in organization of membrane associated proteins, cellular mechanics, adhesion, …

Investigating Drift Mobilities In Cadmium Telluride Solar Cells, Daniel Goldman

Honors Capstone Projects - All

See Abstract within Capstone document

Study Of Edgeless Timepix Pixel Devices, Dylan G. Hsu

Honors Capstone Projects - All

Silicon micropattern devices are crucial components of detector systems designed to study decays of exotic subatomic particles containing beauty and charm quarks. Among the technologies under consideration for use in future particle physics experiments are edgeless silicon pixel detectors. In these devices a state-of-the-art fabrication process is used to create sensors with a nearly full active area, as compared to conventional sensors which have a “guard ring” which is a dead region at the sensor periphery. Prototypes used for the study described in this paper were designed and fabricated by VTT Technical Research Centre of Finland. In a test beam …

Precision Measurement Of The Lambda_B Baryon Lifetime, Bilas Kanti Pal

Dissertations - ALL

The ratio of the Lambda_b baryon lifetime to that of the B0 meson is measured using data corresponding to an integrated luminosity of 3.0 /fb collected with the LHCb detector using pp collisions at the LHC. The Lambda_b baryon is observed in the decay mode Lambda_b ->J/psi p K-, while the B0 meson decay used is the well known B0->J/psi pi+ K- mode, where the pi+K- mass is consistent with that of the K*0(892) meson. The ratio of lifetimes is measured to be 0.971+/-0.007+/-0.005, in agreement with theoretical expectations based on the heavy quark expansion. Using previous determinations …

Measurement Of The Cp Violating Asymmetry A^S_Sl Using Bs0->(Ds->Phi Pi) Mu Nu, Alessandra Borgia

Dissertations - ALL

The time-integrated measurement of the semileptonic CP violating asymmetry, as_sl, with data acquired at the Large Hadron Collider with the LHCb experiment is presented. This measurement can help physicists understand some peculiarities in the Standard Model, which is the fundamental framework of knowledge of the universe. Should this asymmetry diverge from zero, new physics may be a main motivator. Using 1 fb-1 of collected data in 2011 with proton-proton collisions at a center-of-mass energy of 7 TeV, the measured value of as_sl presented is (-0.06 ± 0.50 ± 0.36)%, where the first uncertainty is statistical and the …

Molecular Sensing With Protein And Solid-State Nanopores, David John Niedzwiecki

Physics - Dissertations

In the past 15 years nanopore sensing has proven to be a successful method for probing a variety of molecules of biological interest, such as DNA, RNA and proteins. Of particular appeal is this technique's ability to probe these molecules without the need for chemical modification or labeling, to do so at physiological conditions, and to probe single molecules at a time, allowing the possibility for results masked in bulk measurements to come to light. In this thesis these advantageous properties will be used in work on both a synthetic (solid-state) nanopore system and an engineered biological nanopore. I will …

Particle Physics In The Lhc Era, Don Bunk

Physics - Dissertations

During the past 100 years experimental particle physicists have collected an impressive amount of data. Theorists have also come to understand this data extremely well. It was in the first half of the 20th century the efforts of the early pioneers of quantum mechanics laid the ground work for this understanding: quantum field theory. Through the tireless efforts of researchers during the later half of the 20th century many ideas came together to form what we now call the Standard Model (SM) of particle physics. Finally, it was through the ideas of the renormalization group and effective field theory that …

First Leptonic Probe Of Neutron Radii In Lead At Low-Q2, Chun-Min Jen

Physics - Dissertations

Over the past decade, in Hall-A of the Thomas Jefferson National Accelerator Facility (TJNAF), both the HAPPEX and PREx collaborations have carried out various high-precision polarized elastic electron scattering experiments to explore the nuclear structure, the nucleon form factor and the weak charge of proton and electron. They have done so through the technique of the parity-violating asymmetry measurement with limited theoretical uncertainties. My dissertation focuses on the study of nuclear structure, namely the thickness of the neutron skin, using elastic electron scattering experiments.

The direct measurement of the thickness of the neutron skin in heavy nuclei, where neutron are …

Influence Of Genetic Variation On Birth Defects In Caenorhabditis Elegans, Daniel Robert Kepple

Honors Capstone Projects - All

In my Renee Crown Honors Capstone project, I studied how genetic variation influences birth defects that cause death in C. elegans embryos. I performed high-throughput hatching assay experiments of recombinant inbred advance intercross lines of C. elegans. These lines are genetically distinct from each other. I found significant variation in birth defects causing embryo death in these recombinant inbred advanced intercross lines. My results give evidence that gene interaction may play a significant role in causing birth defects resulting in death. My data also provides a starting point for studies making statistical arguments linking these birth defects to specific …

Research And Development Of The Positron Damping Rings For The Proposed International Linear Collider And At Cern In Geneva, Switzerland For The Large Hadron Collider Atlas Experiment's Integrated Simulation Framwork, Ryan Badman

Honors Capstone Projects - All

The topic of part I of my capstone is electron clouds, studied in the Cornell synchrotron accelerator. Electron clouds are an important phenomenon to study in circular particle accelerators such as the Large Hadron Collider (LHC), the Cornell synchrotron, and the damping ring for the proposed International Linear Collider (ILC). Low energy background electrons are normally present in high energy accelerators and are often not detrimental to beam performance, but certain operation conditions cause them to interact strongly with the beam, as was first observed in the 1980s in positron storage rings. The generation and amplification of the electron cloud …

Where Does The Water Come From? A Temporal Geochemical Characterization Of Water Sources In The Lives Of Storms, Mallory Ringham

Honors Capstone Projects - All

An analysis of the ion chemistry, δ¹⁸O, and δ²H values of precipitation may allow for the characterization of their water sources. As water evaporates, it retains a signature of its source in the ions that it carries and in the amount of fractionation of the oxygen and hydrogen isotopes. Precipitation samples for coastal, lake effect, and continental sources were collected over the months of October- January in Syracuse, New York throughout the duration of each storm, including one hurricane, one thunderstorm, two lake effect snowstorms, and seven rain events. These samples were run through IC, ICP-OES, …

Research And Development Of The Positron Damping Rings For The Proposed International Linear Collider, And At Cern In Geneva, Switzerland For The Large Hadron Collider Atlas Experiment's Integrated Simulation Framework, Ryan Badman

Honors Capstone Projects - All

Abstract not available. Please download the full Capstone for abstract.

Measurement Of The Semileptonic Cp Violating Asymmetry A Sl S In B S Decays And The D S + -- D S - Production Asymmetry In 7 Tev Pp Collisions, Zhou Xing

Physics - Dissertations

The large hadron collider (LHC) at the European Organization for Nuclear Research (CERN) in Geneva is the world's largest and highest-energy particle accelerator. It is located in a tunnel with a circumference of 27 kilometers (17 miles) whose synchrotron is designed to mainly collide opposing particle beams of protons with energy up to 7 TeV in 2011 and 8 TeV in 2012. LHC is designed to address some of the fundamental open questions in physics regarding the basic laws governing the interactions and forces among the elementary particles. Among the four major experiments at LHC: A Toroidal LHC Apparatus (ATLAS), …

Light Trapping For Silicon Solar Cells: Theory And Experiment, Hui Zhao

Physics - Dissertations

Crystalline silicon solar cells have been the mainstream technology for photovoltaic energy conversion since their invention in 1954. Since silicon is an indirect band gap material, its absorption coefficient is low for much of the solar spectrum, and the highest conversion efficiencies are achieved only in cells that are thicker than about 0.1 mm. Light trapping by total internal reflection is important to increase the optical absorption in silicon layers, and becomes increasingly important as the layers are thinned. Light trapping is typically characterized by the enhancement of the absorptance of a solar cell beyond the value for a single …

A Search For Wimp Dark Matter Using An Optimized Chi-Square Technique On The Final Data From The Cryogenic Dark Matter Search Experiment (Cdms Ii)., Manungu Joseph Kiveni

Physics - Dissertations

During the last two decades, cosmology has become a precision observational science thanks (in part) to the incredible number of experiments performed to better understand the composition of the universe. The large amount of data accumulated strongly indicates that the bulk of the universe’s matter is in the form of nonbaryonic matter that does not interact electromagnetically. Combined evidence from the dynamics of galaxies and galaxy clusters confirms that most of the mass in the universe is not composed of any known form of matter. Measurements of the cosmic microwave background, big bang nucleosynthesis and many other experiments indicate that …

Linear Sigma Models In Qcd And S3 Symmetry For Neutrinos, Muhammad Naeem Shahid

Physics - Dissertations

This thesis has two parts with different topics in particle physics. In part I, we consider various linear sigma models and their applications to scalar mesons. It is shown that the tree amplitude for ππ scattering in the minimal linear sigma model has an exact expression which induces an infinite geometric series in which the pattern for both the I = 0 and I = 2 s-wave scattering lengths to orders $p^2$, $p^4$ and $p^6$ seems to agree with chiral perturbation theory predictions. The model is then gauged to study the mass differences between the vector meson and the axial …

Microstrip Superconducting Quantum Interference Devices For Quantum Information Science, Michael Paul Defeo

Physics - Dissertations

Quantum-limited amplification in the microwave frequency range is of both practical and fundamental importance. The weak signals corresponding to single microwave photons require substantial amplification to resolve. When probing quantum excitations of the electromagnetic field, the substantial noise produced by standard amplifiers dominates the signal, therefore, several averages must be accumulated to achieve even a modest signal-to-noise ratio. Even worse, the back-action on the system due to amplifier noise can hasten the decay of the quantum state. In recent years, low-noise microwave-frequency amplification has been advancing rapidly and one field that would benefit greatly from this is circuit quantum electrodynamics …

Measurement Of Neutron Radius In Lead By Parity Violating Scattering Flash Adc Daq, Ahmed Zafar

Physics - Dissertations

This dissertation reports the experiment PREx, a parity violation experiment which is designed to measure the neutron radius in ²⁰⁸Pb. PREx is performed in hall A of Thomas Jefferson National Accelerator Facility from March 19th to June 21st. Longitudionally polarized electrons at energy 1 GeV scattered at and agnle of θl_ab = 5.8° from the Lead target. Beam corrected pairty violaing counting rate asymmetry is (A_corr = 594 ± 50(stat) ± 9(syst))ppb at Q² = 0.009068GeV^2.

This dissertation also presents the details of Flash ADC Data Acquisition(FADC DAQ) system …

Development Of Spect And Ct Tomographic Image Reconstruction, Levon Orion Vogelsang

Physics - Dissertations

The purpose of this study was to contribute to the advancement of statistically-based iterative reconstruction algorithms and protocols for both SPECT and micro CT data. Major contributions of this work to SPECT reconstruction include formulation and implementation of fully three-dimensional voxel-based system matrix in parallel-beam, fan-beam, and cone-beam collimator geometries while modeling the process of attenuation, system resolution and sensitivity. This is achieved by casting rays through a volume of voxels and using ray-voxel intersection lengths to determine approximate volume contributions. Qualitative and quantitative analysis of reconstructed Monte Carlo data sets show that this is a very effective and efficient …

Effective Field Theories In Cosmology, Riccardo Penco

Physics - Dissertations

During the last 20 years, a large amount of detailed cosmological observations have promoted cosmology to the rank of high-precision science. Remarkably, all the observations currently available can be accounted for by assuming that (i) the universe is approximately homogeneous and isotropic on large scales, (ii) gravitational interactions are described by General Relativity with a non-vanishing cosmological constant and (ii) 85% of the matter content of the universe is in the form of dark matter, a presently unknown type of matter which interacts with ordinary matter only gravitationally. Current theoretical efforts are focused on …

Physics On Noncommutative Spacetimes, Pramod Padmanabhan

Physics - Dissertations

The structure of spacetime at the Planck scale remains a mystery to this date with a lot of insightful attempts to unravel this puzzle. One such attempt is the proposition of a `pointless' structure for spacetime at this scale. This is done by studying the geometry of the spacetime through a noncommutative algebra of functions defined on it. We call such spacetimes 'noncommutative spacetimes'. This dissertation probes physics on several such spacetimes. These include compact noncommutative spaces called fuzzy spaces and noncompact spacetimes. The compact examples we look at are the fuzzy sphere and the fuzzy Higg's manifold. The noncompact …

Geometries In Soft Matter, Zhenwei Yao

Physics - Dissertations

No abstract provided.

The Design And Construction Of A Green Laser And Fabry-Perot Cavity System For Jefferson Lab's Hall A Compton Polarimeter, Abdurahim Rakhman

Physics - Dissertations

A high finesse Fabry-Perot cavity with a frequency doubled green laser (CW, 532 nm) have been built and installed in Hall A of Jefferson Lab for high precision Compton polarimetry project in spring of 2010. It provides a high intensity circularly polarized photon target for measuring the polarization of electron beam with energies from 1.0 GeV to 11.0 GeV in a nondestructive manner. The IR beam (CW, 1064 nm) from a Ytterbium doped fiber laser amplifier seeded by a Nd:YAG narrow linewidth NPRO laser is frequency doubled in by a single-pass Periodically Poled Lithium Niobate (PPMgLN) crystal. The maximum achieved …

Characterization Of Enhanced Interferometric Gravitational Wave Detectors And Studies Of Numeric Simulations For Compact-Binary Coalescences, Larne Pekowsky

Physics - Dissertations

Gravitational waves are a consequence of the general theory of relativity. Direct detection of such waves will provide a wealth of information about physics, astronomy, and cosmology. A worldwide effort is currently underway to make the first direct detection of gravitational waves. The global network of detectors includes the Laser Interferometer Gravitational-wave Observatory (LIGO), which recently completed its sixth science run.

A particularly promising source of gravitational waves is a binary system consisting of two neutron stars and/or black holes. As the objects orbit each other they emit gravitational radiation, lose energy, and spiral inwards. This produces a characteristic ``chirp'' …

Searching For Gravitational Waves From Compact Binary Coalescence Using Ligo And Virgo Data, Collin Capano

Physics - Dissertations

This thesis describes current efforts to search for gravitational waves from compact binary coalescences (CBCs) by the LIGO Scientific Collaboration (LSC) and the Virgo Collaboration. We briefly review the physics of gravitational-wave emission and detection, describing how gravitational waves are emitted from "inspiraling" compact stellar mass objects and how the LSC and Virgo try to detect them using interferometers. Next we review the data-analysis principles used to search for potential signals in the detectors' noise. These principles are employed by ``ihope," which is the data-analysis pipeline used to search for CBCs. We describe each step in this pipeline and discuss …

Interacting Stochastic Processes: From Viciousness To Caging To Force Chains, Shiliyang Xu

Physics - Dissertations

This thesis documents a quest to develop and study several novel interacting stochastic processes. As for the first example, we generalize a system of vicious random walkers in which the only interaction between any two random walkers is that when they intersect, both walkers are annihilated. We define a system of N vicious accelerating walkers with each walker undergoing random acceleration and compute the survival probability distribution for this system. We also define and study a system of N vicious Levy flights in which any two Levy flights crossing one another annihilate each other. The average mean-squared displacement of a …

Higher Derivative Gravitational Systems And Ghost Fields, Michele Fontanini

Physics - Dissertations

Effective Field Theory (EFT) is one of the most powerful theoretical tools in the hands of cosmologists, it allows them to come up with testable effective descriptions of the universe even when a fundamental theory is missing. EFT though, is not the only possible answer for pushing our knowledge beyond the limits of what has already been established. Applying EFT and other alternative methods has become an important part of a cosmologist’s work, particularly in the last few years when a vast plethora of extensions of the Standard Model of Cosmology has been proposed and needs to be tested against …

A Biosynthetic Membrane-Anchor/Protein System Based On A Genetically Encoded "Aldehyde Tag", Chaojie Zhen

Honors Capstone Projects - All

Lipid membranes or bilayers serve as barriers for the cell and its organelles. A distinguishing feature of cellular function is the ability to monitor and process the biochemical information between the cells’ intra and extracellular environments in order to maintain the homeostatic reactions that are essential to life. Surface membrane proteins play a key role in mediating this information exchange by functionalizing the bilayer. As a result of their importance in living systems, proteins are integrated into biomimetic membrane systems to replicate their natural functions in biomedical technologies. Current protein integration methods are limited by the selection of commercially available …

Topics In Cosmic Acceleration And Braneworlds, Eric J. West

Physics - Dissertations

Cosmic acceleration has come to be a standard, and perhaps required, ingredient in our current understanding of the universe. In the early universe, under the name of inflation, a phase of accelerated expansion is used to solve many problems with the standard Hot Big Bang cosmology. In the late universe, cosmic acceleration seems to best explain a wide variety of observations. In both cases, we lack a complete theory of what drives cosmic acceleration. In this thesis I discuss some open issues in our understanding of cosmic acceleration, both in the early and late universe.