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Full-Text Articles in Physics

Supergravity Backgrounds For Deformations Of Adsn×Sn Supercoset String Models, Oleg Lunin, Radu Roiban, Arkady Tseytlin Dec 2014

Supergravity Backgrounds For Deformations Of Adsn×Sn Supercoset String Models, Oleg Lunin, Radu Roiban, Arkady Tseytlin

Physics Faculty Scholarship

We consider type IIB supergravity backgrounds corresponding to the deformed AdS_n x S^n supercoset string models of the type constructed in arXiv:1309.5850 which depend on one deformation parameter k. In AdS_2 x S^2 case we find that the deformed metric can be extended to a full supergravity solution with non-trivial dilaton, RR scalar and RR 5-form strength. The solution depends on a free parameter (called a) that should be chosen as a particular function of k to correspond to the deformed supercoset model. In AdS_3 x S^3 case the full solution supported by the dilaton, RR scalar and RR 3-form …


A Potential Foundation For Emergent Space-Time, Kevin H. Knuth, Newshaw Bahreyni Nov 2014

A Potential Foundation For Emergent Space-Time, Kevin H. Knuth, Newshaw Bahreyni

Physics Faculty Scholarship

We present a novel derivation of both the Minkowski metric and Lorentz transformations from the consistent quantification of a causally ordered set of events with respect to an embedded observer. Unlike past derivations, which have relied on assumptions such as the existence of a 4-dimensional manifold, symmetries of space-time, or the constant speed of light, we demonstrate that these now familiar mathematics can be derived as the unique means to consistently quantify a network of events. This suggests that space-time need not be physical, but instead the mathematics of space and time emerges as the unique way in which an …


Physics: Rethinking The Foundations, Kevin H. Knuth Oct 2014

Physics: Rethinking The Foundations, Kevin H. Knuth

Physics Faculty Scholarship

Physics is traditionally conceived of as a set of laws that universally governs the behavior of physical systems. These laws, however they are decreed, are believed to govern the behavior of not only everything in the universe, but the form of the universe itself. However, this traditional concept of physics as a universal governance is at odds with our modern theories of quantum mechanics and relativity, which place the observer and information in a central role. In this talk, I aim to rethink the foundations and attempt to build physics from the bottom up based on a very simple foundational …


Momentum And Spin In Entropic Quantum Dynamics, Shahid Nawaz Jan 2014

Momentum And Spin In Entropic Quantum Dynamics, Shahid Nawaz

Legacy Theses & Dissertations (2009 - 2024)

We study quantum theory as an example of entropic inference. Our goal is to remove conceptual difficulties that arise in quantum mechanics. Since probability is a common feature of quantum theory and of any inference problem, we briefly introduce probability theory and the entropic methods to update probabilities when new information becomes available. Nelson's stochastic mechanics and Caticha's derivation of quantum theory are discussed in the subsequent chapters. Our first goal is to understand momentum and angular momentum within an entropic dynamics framework and to derive the corresponding uncertainty relations. In this framework momentum is an epistemic concept -- it …


Energy Dependence Of Deuteron Induced Nuclear Reaction Cross Sections On Li, Be, B, C, N, O, And F, Mathew Parenti Jan 2014

Energy Dependence Of Deuteron Induced Nuclear Reaction Cross Sections On Li, Be, B, C, N, O, And F, Mathew Parenti

Legacy Theses & Dissertations (2009 - 2024)

Nuclear reactions induced by 1.2 MeV deuteron on 9Be and 19F are studied with the goal of developing a practical analysis method for these light elements. In addition, the energy dependence of deuteron induced nuclear reactions on 7Li, 9Be, 11B, 12C, 14N, 16O, and 19F was measured. The energy dependence of these nuclear reactions allows the nuclear reaction analysis for these light elements to be corrected for the energy loss of the incident deuteron ions in the analyzed film.


Fundamental Studies Of Supported Graphene Interfaces : Defect Density Of States In Graphene Field Effect Transistors (Fets) And Ideal Graphene - Silicon Schottky Diodes, Dhiraj Sinha Jan 2014

Fundamental Studies Of Supported Graphene Interfaces : Defect Density Of States In Graphene Field Effect Transistors (Fets) And Ideal Graphene - Silicon Schottky Diodes, Dhiraj Sinha

Legacy Theses & Dissertations (2009 - 2024)

The physics of transport in atomically thin 2D materials is an active area of research, important for understanding fundamental properties of reduced dimensional materials and for applications. New phenomena based on graphene may include properties of topologically protected insulators. Applications of these materials are envisioned in electronics, optoelectronics and spintronics.


Probing Secondary And Tertiary Rna Folding Using Force And Temperature, William Stephenson Jan 2014

Probing Secondary And Tertiary Rna Folding Using Force And Temperature, William Stephenson

Legacy Theses & Dissertations (2009 - 2024)

RNA folding is the process whereby a single stranded RNA molecule assumes its three-dimensional functional conformation. Along with the protein folding problem, the RNA folding problem remains as one of the great unsolved problems in biophysics. Generally RNA folding occurs in a hierarchical manner whereby the sequence of an RNA (primary structure) determines which regions will form helical segments (secondary structure) before further rearrangement and base pairing of secondary structure motifs (tertiary structure). Due to the intimate connection between structure and function within molecular biology, increased familiarity with the thermodynamic and kinetic factors that govern RNA folding will permit the …


Growth And Characterization Of Graphene On Cuni Substrates, Parul Tyagi Jan 2014

Growth And Characterization Of Graphene On Cuni Substrates, Parul Tyagi

Legacy Theses & Dissertations (2009 - 2024)

Graphene is a single layer of sp2 bonded carbon atoms that crystallizes in the honeycomb structure. Because of its true two-dimensional structure, it has very unique electrical properties, including a very high carrier mobility that is symmetric for holes and electrons. To realize these unique properties, it is important to develop a method for growing graphene films with uniform thickness and low defect density. One of the most popular methods of growth is by chemical vapor deposition on Cu substrates, because it is self-limited. However many applications require the growth of graphene films that are more than one atomic layer …


Experimental And Simulation Studies Of Printability Of Buried Euv Mask Defects And Study Of Euv Reflectivity Loss Mechanisms Due To Standard Euv Mask Cleaning Processes, Mihirkant Upadhyaya Jan 2014

Experimental And Simulation Studies Of Printability Of Buried Euv Mask Defects And Study Of Euv Reflectivity Loss Mechanisms Due To Standard Euv Mask Cleaning Processes, Mihirkant Upadhyaya

Legacy Theses & Dissertations (2009 - 2024)

There's a big push for development and commercialization of extreme ultraviolet (EUV) lithography for high-volume semiconductor manufacturing of 14 nm half-pitch patterning and beyond. One of the primary concerns for making this a reality has been the ability to achieve defect-free masks. My study is focused on two aspects related to the performance degradation of the EUV masks namely EUV mask cleaning induced reflectivity loss mechanisms, and the buried multilayer phase defects in EUV masks.


First-Principles Study Of The Electric Field Effect On The Water-Adsorbed Rutile Titanium Dioxide Surface, Abraham L. Hmiel Jan 2014

First-Principles Study Of The Electric Field Effect On The Water-Adsorbed Rutile Titanium Dioxide Surface, Abraham L. Hmiel

Legacy Theses & Dissertations (2009 - 2024)

TiO2 is a semiconducting material that has been used extensively in many industrial applications, and recently has become a candidate for photocatalytic water splitting, fuel cell anode support materials, sensors, and other novel nanodevices. The interface of TiO2 with water, historically well-studied but still poorly understood, presents a ubiquitous environmental challenge towards the ultimate practical usefulness of these technologies. Ground-state density functional theory (DFT) calculations studying the characteristics of molecular adsorption on model surfaces have been studied for decades, showing constant improvement in the description of the energetics and electronic structure at interfaces. These simulations are invaluable in the …


Coherent Scatter Imaging For Mammography, Katie Kern Jan 2014

Coherent Scatter Imaging For Mammography, Katie Kern

Legacy Theses & Dissertations (2009 - 2024)

Traditional x-ray images are good at distinguishing between materials with different absorption coefficients. The problem with mammography stems from the fact that there is very low contrast between cancerous and normal tissue types. Since cancerous and normal tissue have similar absorption coefficients, using conventional x-ray imaging to distinguish between the two is difficult. Coherent scatter is an alternative method to detect cancerous material within human breast tissue. Coherent scatter can distinguish between tissue types, if the intermolecular spacing of the tissues differ.


Metal Oxide Growth, Spin Precession Measurements And Raman Spectroscopy Of Cvd Graphene, Akitomo Matsubayashi Jan 2014

Metal Oxide Growth, Spin Precession Measurements And Raman Spectroscopy Of Cvd Graphene, Akitomo Matsubayashi

Legacy Theses & Dissertations (2009 - 2024)

The focus of this dissertation is to explore the possibility of wafer scale graphene-based spintronics. Graphene is a single atomic layer of sp2 bonded carbon atoms that has attracted much attention as a new type of electronic material due to its high carrier mobilities, superior mechanical properties and extremely high thermal conductivity. In addition, it has become an attractive material for use in spintronic devices owing to its long electron spin relaxation time at room temperature. This arises in part from its low spin-orbit coupling and negligible nuclear hyperfine interaction. In order to realize wafer scale graphene spintronics, utilization of …


Measurement Of The Ttbar Interaction Cross Section In The Tau+Jets Decay Channel Via Multivariable Template Fitting Of 4.6 Fb-1 Of Data Collected At √S = 7 Tev By The Atlas Detector, William Edson Jan 2014

Measurement Of The Ttbar Interaction Cross Section In The Tau+Jets Decay Channel Via Multivariable Template Fitting Of 4.6 Fb-1 Of Data Collected At √S = 7 Tev By The Atlas Detector, William Edson

Legacy Theses & Dissertations (2009 - 2024)

This analysis measured the entire ttbar cross section through the specific decay channel to a tau, tau neutrino and four quark jets utilizing the full 2011 ATLAS collected data sample of 4.6fb-1. Measurement was achieved by creating templates based on Monte Carlo samples for the various well-modeled background and signal in conjunction with a data-driven derived template for QCD multijet samples. Signal separation was achieved by utilizing Boosted Decision Tree multi-variables designed to identify true from fake taus. The final result was determined to be 165.8 ±9.9 (𝑠𝑡𝑎𝑡.)− 30.0+ 29.7(𝑠𝑦𝑠𝑡.)±3.0(𝑙𝑢𝑚𝑖.) pb which is in agreement with previous measurements of this …


Diffraction-Based Techniques For High Contrast X-Ray Imaging, Lubna Naseem Peerzada Jan 2014

Diffraction-Based Techniques For High Contrast X-Ray Imaging, Lubna Naseem Peerzada

Legacy Theses & Dissertations (2009 - 2024)

Two X-ray diffraction based techniques for high contrast were explored to improve contrast in radiology: diffraction enhanced imaging (DEI) and coherent scatter imaging.


Power Law Models Of Stock Indices, Mankit Tse Jan 2014

Power Law Models Of Stock Indices, Mankit Tse

Legacy Theses & Dissertations (2009 - 2024)

Viewing the stock market as a self-organized system, Sornette and Johansen introduced physics-based models to study the dynamics of stock market crashes from the perspective of complex systems. This involved modeling stock market Indices using a mathematical power law exhibiting log-periodicity as the system approaches a market crash, which acts like a critical point in a thermodynamic system. In this dissertation, I aim to investigate stock indices to determine whether or not they exhibit log-periodic oscillations, according to the models proposed by Sornette, as they approach a crash. In addition to analyzing stock market crashes in the frequency domain using …


A Brownian Dynamics Approach To Esr Line Shape Calculations, Matthew Wright Jan 2014

A Brownian Dynamics Approach To Esr Line Shape Calculations, Matthew Wright

Legacy Theses & Dissertations (2009 - 2024)

The work presented in this thesis uses a Monte Carlo technique to simulate spectra for 14N spin-labels and 15N spin labels. The algorithm presented here also has the capability to produce simulated spectra for any admixture of 14N and 15N. The algorithm makes use of `iterative loops' to model Brownian rotational diffusion and for the repeated evaluation of the spectral correlation function (relaxation function).