Physics Commons^™

Gravitational Wave Production Through Decay Of The Inflaton Into Intermediary Fields During Slow Roll Inflation, Jessica Lauren Cook

Open Access Dissertations

This dissertation looks for possible observable signals of tensor metric perturbations sourced during slow roll inflation from decay of the inflaton field into other intermediary fields. We focus on two main scenarios, one of explosive production of intermediary fields for a short period during inflation and another of prolonged production of vectors due to a derivative coupling of the vectors with the inflaton field. We only find a possible observable signal of tensor perturbations in the second case.

Conditional Gaussian Fluctuations And Refined Asymptotics Of The Spin In The Phase-Coexistence Region, Jingran Li

Open Access Dissertations

In this dissertation four results are presented on the fluctuations of the spin per site around the thermodynamic magnetization in the mean-field Blume-Capel model, a basic model in statistical mechanics. The first two results refine the main theorem in a 2010 paper by R. S. Ellis, J. Machta, and P. T. Otto published in Annals of Applied Probability 20 (2010) 2118-2161. This paper provides the first rigorous confirmation of the statistical mechanical theory of finite-size scaling for a mean-field model. The first main result studies the asymptotics of the centered, finite-size magnetization, giving its precise rate of convergence to 0 …

Replica Exchange Monte Carlo Simulations Of The Ising Spin Glass: Static And Dynamic Properties, Burcu Yucesoy

Open Access Dissertations

Spin glasses have been the subject of intense study and considerable controversy for decades, and the low-temperature phase of short-range spin glasses is still poorly understood. Our main goal is to improve our understanding in this area and find an answer to the following question: Are there only a single pair or a countable infinity of pure states in the low temperature phase of the EA spin glass? To that aim we first start by introducing spin glasses and provide a brief history of their research, then proceed to describe our method of simulation, the parallel tempering Monte Carlo algorithm. …

Charge Transport Studies Of Proton And Ion Conducting Materials, Craig William Versek

Open Access Dissertations

The development of a high-throughput impedance spectroscopy instrumentation platform for conductivity characterization of ion transport materials is outlined. Collaborative studies using this system are summarized. Charge conduction mechanisms and conductivity data for small molecule proton conducting liquids, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, and select mixtures of these compounds are documented. Furthermore, proton diffusivity measurements using a Pulse Field Gradient Nuclear Magnetic Resonance (PFG NMR) technique for imidazole and 1,2,3-triazole binary mixtures are compared. Studies of azole functionalized discotic and linear mesogens with conductivity, structural, and thermal characterizations are detailed.

The Effect Of Vesicle Shape, Line Tension, And Lateral Tension On Membrane-Binding Proteins, Jaime Bosart Hutchison

Open Access Dissertations

Model membranes allow for the exploration of complex biological phenomena with simple, controllable components. In this thesis we employ model membranes to determine the effect of vesicle properties such as line tension, lateral tension, and shape on membrane-binding proteins. We find that line tension at the boundary between domains in a phase separated vesicle can accumulate model membrane-binding proteins (green fluorescent protein with a histidine tag), and that those proteins can, in turn, alter vesicle shape. These results suggest that domains in biological membranes may enhance the local concentration of membrane-bound proteins and thus alter protein function. We also explore …

A Measurement Of The W/Z Cross Section Ratio As A Function Of Hadronic Activity With The Atlas Detector, Andrew Robert Meade

Open Access Dissertations

Hadronic collisions at the LHC at CERN probe particle interactions at the highest energy scale of any experiment to date. We present a research program measuring R_jet = &sigma_WBR(W&rarr&mu&nu) / (&sigma_ZBR(Z&rarr&mu&mu)) as a function of a number of hadronic variables. The measurements are performed with the ATLAS detector at the LHC, using the 2011 data set, consisting of 4.64 fb-1 of pp collisions at a center of mass energy of 7 TeV. This measurement is a robust way to test the Standard Model and the modeling of perturbative QCD, and is sensitive to a wide …

Investigations Of Surface-Tension Effects Due To Small-Scale Complex Boundaries, Jiansheng Feng

Open Access Dissertations

The earliest man-made irrigation systems in recorded history date back to the ancient Egypt and Mesopotamia era. After thousands of years of experience, exploration, and experimenting, mankind have learned how to construct canals and dams and use pipes and pumps to direct and control water flow, but till this day, there are still some behaviors of water and other simple fluids that surprise us. One such example is the lotus effect: a surface-tension effect which allows raindrops to roll freely on a lotus leaf as if they were drops of mercury. One of the key factors that determine how a …

Pattern Formation In Floating Sheets, Hunter King

Open Access Dissertations

This thesis presents a study of two basic modes of deformation of a thin sheet: wrinkling and crumpling, viewed primarily in the context of an elastic sheet confined by capillary forces on a drop of liquid.

First, it provides a brief conceptual background in the relevant physics of thin sheet mechanics and capillarity and introduces the general principles of wrinkling and crumpling.

The problem of confining a circular sheet on an increasingly curved spherical drop is presented as a vehicle to explore these principles. At finite curvature, the sheet is seen to wrinkle around its outer edge. At large confinement, …

Measuring Proton Spin Polarizabilities With Polarized Compton Scattering, Philippe Paul Martel

Open Access Dissertations

Polarized nuclear Compton scattering on a proton target provides a test of low energy QCD. The beam-target asymmetries of a circularly polarized Bremsstrahlung photon beam on a transversely polarized butanol target (&Sigma_2x) and on a longitudinally polarized butanol target (&Sigma_2z), and the beam asymmetry of a linearly polarized Bremsstrahlung beam on an unpolarized hydrogen target (&Sigma₃) are sensitive to the proton spin polarizabilities, third order terms in the energy expansion of the Compton scattering amplitude. This experiment consisted of the &Sigma_2x measurement, both just below and above two-pion threshold.