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Now showing items 21-30 of 116

#### Device Physics of Two-Dimensional Crystalline Materials

The study of two-dimensional (2D) electrons in condensed matter physics has two milestones: quantum Hall effects in semiconductor heterostructures and superconductivity in cuprates. In both, the 2D electrons are embedded in complex material structures. The discovery of graphene allows for the isolation of 2D electrons in their ...

#### Multiphysics Simulation of Nanostructured Semiconductor Devices

(2014-02-24)

This dissertation describes how to utilize multiphysics simulation techniques to develop physical (optics and device) models of nanostructured semiconductor devices. A hierarchy of approaches (ab-initio, continuum, transfer-matrix, finite-difference time-domain) is used to bridge the gaps in computational efficiency and ...

#### Applications of Quantum Field Theory, From the Formal to the Phenomenological

Much of the beautiful and complex phenomenology of the Standard Model can be traced back to the presence of chiral symmetries, both global and local, and nonperturbative phenomena. Without chiral symmetries (and the anomalous ways that they can be broken), there would be no flavor physics or CP violation. Without a strongly ...

#### Developments in the Theory of X-ray Absorption and Compton Scattering.

X-ray spectroscopy is a widely used technique in experimental and theoretical physics for studying electronic and chemical properties of materials. Theoretical approaches for studying x-ray absorption (XAS) and x-ray photoemision (XPS) properties are described by single particle Green’s function theory. In strongly correlated ...

#### The role of nuclear physics in supernovae and the evolution of neutron stars, Neutrino Opacities, Equation of State, Transport Coefficients, and Dark Matter Production

A massive star, of at least eight solar masses, end their life cycle in a sudden, catastrophic collapse under its own gravity. In a thousandth of a second, it can shrink from thousands of kilometers across to a ball of ultra-condensed matter just a few kilometers across. Ultimately, it all ends in a cataclysmic explosion known ...

#### Searches for Beyond Standard Model Higgs Bosons in pp collisions at sqrt(s) = 8 and 13 TeV with the ATLAS detector

The searches for a Beyond Standard Model (BSM) heavy CP-odd Higgs boson $A$ decaying to $Zh$ in the context of two-Higgs-doublet models (2HDM), and Minimal Supersymmetric Standard Model (MSSM) neutral Higgs bosons $H/A$ decaying to a tau pair are presented. The search for the heavy CP-odd Higgs boson, $A$, is conducted through ...

#### Holographic Tools for Probing the Dynamics of Strongly Coupled Field Theories

Since it was conjectured almost 20 years ago, AdS/CFT duality, or holography, has enabled steady progress in understanding certain gauge theories in the strongly coupled limit. In this thesis we examine various aspects of holography and holographic techniques, as well as particular applications to the dynamics of strongly ...

#### A search for hep solar neutrinos at the Sudbury Neutrino Observatory

Solar neutrinos from the fusion hep reaction, (helium-3 fusing with a proton to become helium-4, releasing a positron and neutrino), have previously remained undetected due to their flux being about one one-thousandth that of boron-8 neutrinos. These neutrinos are interesting theoretically because they are less dependent on ...

#### Searching for neutrinoless double-beta decay of germanium-76 in the presence of backgrounds

(2013-04-17)

The neutrino, an elementary particle, has been the subject of experimental investigation for over 50 years. Recent experiments have shown that neutrinos have mass and oscillate, but questions about fundamental properties of the neutrino remain. The observation of neutrinoless double-beta decay could determine whether lepton ...

#### Hubbard Model Approach to X-ray Spectroscopy

(2013-02-25)

We have implemented a Hubbard model based first-principles approach for real-space calculations of x-ray spectroscopy, which allows one to study excited state electronic structure of correlated systems. Theoretical understanding of many electronic features in d and f electron systems remains beyond the scope of conventional ...