Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 28 for “"Sigma Models"”.
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Sigma Models with Repulsive Potentials
<p>Motivated by questions arising in the study of harmonic maps and Yang Mills theory, we study new techniques for producing optimal monotonicity relations for geometric partial differential equations. We apply these results to sharpen epsilon regularity results. As a sample application, we analyze …
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Aspects of Topological Sigma Models
… subsector of certain N = (0, 2) nonlinear sigma models1 is. Additionally, A-twisted Landau-Ginzburg models---twisted nonlinear sigma models with superpotentials---are analyzed and related via renormalization group flow to correlation functions in topological conformal field theories. In …
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Applications of gauged linear sigma models
… to a study of applications of gauged linear sigma models. First, by constructing (0,2) analogues of Hori-Vafa mirrors, we have given and checked proposals for (0,2) mirrors to projective spaces, toric del Pezzo and Hirzebruch surfaces with tangent bundle deformations, checking not only …
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Two-dimensional twisted sigma models and chiral differential operators
We explore a variety of two-dimensional twisted sigma models at the perturbative level in an attempt to furnish purely physical interpretations of various mathematical theories involving a??Chiral Differential Operatorsa?? (or CDOa??s) defined and constructed by mathematicians in recent times. In …
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Linear Sigma Models in QCD and S3 Symmetry for Neutrinos
… 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 …
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PERFECT FLUIDS AND SIGMA MODELS: A MATHEMATICAL INVESTIGATION BETWEEN GENERAL RELATIVITY AND COTTON GRAVITY
In this thesis, we deal with two physics-inspired structures on Riemannian manifolds, depending on a smooth map φ between Riemannian manifolds and several other functions and constants; they are called Cotton φ-Perfect Fluids (C-φ-PF) and φ-static perfect fluids space-times (φ-SPFST). The latter …
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Aspects of Supersymmetry
… In two dimensions, general 𝒩 = (2, 2) nonlinear sigma models on S² are constructed, both for chiral multiplets and twisted chiral multiplets. The explicit curvature coupling terms and their effects are discussed. Finally, 𝒩 = (0, 2) gauged linear sigma models with nonabelian gauge groups are …
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Chiral Rings of Two-dimensional Field Theories with (0,2) Supersymmetry
… in general two-dimensional (0,2) nonlinear sigma models, both in theories twistable to the A/2 or B/2 model, as well as in non-twistable theories. As a special case, we study the quantum sheaf cohomology of Grassmannians as a deformation of the usual quantum cohomology. The deformation …
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Notes on Some (0,2) Supersymmetric Theories in Two Dimensions
… Examples of two-dimensional (0,2) gauged linear sigma models (GLSMs) are constructed for various spaces including Grassmannians, complete intersections in Grassmannians, and non-complete intersections such as Pfaffians. Generalizations of (2,2) Toda dual theories to (0,2) Toda-like theories are …
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Superprobability on Graphs
… The Gaussian free field is a spin system (or sigma model) that takes values in Euclidean space; in this work, we generalise the classical isomorphism theorems to spin systems taking values in hyperbolic and spherical geometries. The corresponding random walks are no longer Markovian: they are …
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On extended supersymmetry in two and four dimensions.
… with describing physics of two dimensional N = 2 sigma models, geometry of their target spaces, their BPS spectra, and how they can de derived from four dimensional theories via BPS vortex construction. Two different approaches { gauge and geometric, as tools to study 2d theories, are compared in …
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Supersymmetric Backgrounds in string theory
… $mathcal{N}=(2,2)$ supersymmetric gauged linear sigma models, describing intersections of Grassmannians. In the next part, we consider mirror symmetry for certain gauge theories with gauge groups $F_4$, $E_6$, and $E_7$. In the last part of this thesis, we study whether certain …
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Studies of superconformal field theories using GLSM and conformal bootstrap
… = (0, 2) gauge theories using the gauged linear sigma models (GLSM). In those theories, we identify simple mechanism by which worldsheet description of H-flux satisfying Green-Schwarz Bianchi identity arises. Under the renormalization group flow, we argue that these models flow into …
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On algebraic singularities, finite graphs and D-brane gauge theories : a string theoretic perspective -- with a digression on string field theory
… as well as the physics, such as gauged linear sigma models, geometrical engineering, Hanany-Witten setups and D-brane probes. We present the work of the author in the past 4 years at the Centre for Theoretical Physics, on aspects of the world-volume gauge dynamics using D-brane resolutions of …
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Low Dimensional Supersymmetric Gauge Theories and Mathematical Applications
This thesis studies N=(2,2) gauged linear sigma models (GLSMs) and three-dimensional N=2 Chern-Simons-matter theories and their mathematical applications. After a brief review of GLSMs, we systematically study nonabelian GLSMs for symplectic and orthogonal Grassmannians, following up a proposal in …
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Duality and dynamics of supersymmetric field theories from D-branes on singularities
… the multiplicity of fields in the gauged linear sigma models associated with the probed geometries. We introduce a straightforward procedure for the determination of toric dual theories and partial resolutions based on the (p, q) web description of toric singularities. We study the non-conformal …
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Applying Six Sigma to Tenneco Automotive manufacturing
… Fortune 500 companies have had with Six Sigma. The information was obtained through a series of interviews with people, mostly senior managers, who have had direct experience leading a portion of their company's Six Sigma efforts. ** Six Sigma Models: This section reports the financial …
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Morita Equivalence and Generalized Kähler Geometry
… which arises in the study of supersymmetric sigma models in physics. In this thesis, we solve the problem of determining the underlying degrees of freedom for the class of GK structures of symplectic type. This is achieved by giving a reformulation of the geometry whereby it is represented by …
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Vignettes in string theory : using geometry to probe the worldsheet and strongly coupled physics
In this thesis, we construct hybrid linear models in which the chiral anomaly of a gauged linear sigma model is canceled by the classical anomaly of a gauged WZW model. Semi-classically, this corresponds to fibering the WZW model over the naive target space of the sigma model. When the gauge group …
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A Study on Heterotic Target Space Duality – Bundle Stability/Holomorphy, F-theory and LG Spectra
In the context of (0, 2) gauged linear sigma models, we explore chains of perturbatively dual heterotic string compactifications. The notion of target space duality (TSD) originates in non-geometric phases and can be used to generate distinct GLSMs with shared geometric phases leading to apparently …
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