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 31 for “"Sigma Model"”.
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Gauged Linear Sigma Model and Mirror Symmetry
… thesis is devoted to the study of gauged linear sigma models (GLSMs) and mirror symmetry. The first chapter of this thesis aims to introduce some basics of GLSMs and mirror symmetry. The second chapter contains the author's contributions to new exact results for GLSMs obtained by applying …
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A study of the chiral phase transition in the nonlinear sigma model
… studied using the three dimensional non-linear sigma model. Numerical simulations with the U(N) $\times$ U(N) and SU(N) $\times$ SU(N) flavor symmetries for both two and three flavors were examined to determine the order of the phase transition. The data from the simulations in the appropriate …
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A study of the chiral phase transition in the non-linear sigma model
… is studied using the three dimensional nonlinear sigma model. Numerical simulations with the U(N) x U(N) and SU(N) x SU(N) flavor symmetries for both two and three flavors were examined to determine the order of the phase transition. The data from the simulations in the appropriate limits was …
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The Applicability of the Human Sigma Model to Service Quality Management in the UK Tourism Industry: an operational analysis
… improvement has adopted a new approach: Human Sigma (Fleming and Asplund, 2007). This new approach has signified a shift away from isolated employee and customer satisfaction scales, described as meeting expectations, to an examination of the more powerful and emotional dimensions of engagement …
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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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Topological field theories and fractional statistics
… of the manifold, g. We study the non-linear sigma model with a Chern-Simons term. We find the canonical structures of the model using Dirac bracket, accounting for the non-trivial constraints of the sigma-model. We show that solutions to the field equation are represented by solitons. We also …
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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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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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Some problems of quantum cosmology and dark matter physics
… the Robertson-Walker metric in the non-linear $\sigma$ model. We find that initially the universe exists in a series of metastable bound states with the scale factor taking discrete values. Then it tunnels through a barrier and comes out in an inflationary state. This tunneling (or evolution 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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AdS3 Holography from the Worldsheet
… S^3 \times T^4$ can be naturally understood as a sigma model on the minitwistor space of $AdS_3$. The incidence relations are studied, showing how they encode both bulk and boundary physics simultaneously. The sigma model we present has several important differences with conventional twistor …
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Semiclassical Methods in Field Theories: The Use of Soliton and Instanton
… thesis concerns with the instanton physics in Sigma model and in nonabelian gauge theory. An instanton solution defines a dominant collective coordinate. By considering only the quantum physics along these coordinates (a good approximation in weak coupling limit), we can reduce a complicated …
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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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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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NEW GRAVITATIONAL INTERACTIONS IN COSMOLOGY —- FROM EFFECTIVE FIELD THEORY TO OBSERVATION
… cosmic epochs, and proposing a theoretical model that suggests an interaction between neutrinos and gravity could help alleviate this tension. I then turn to more formal considerations of Effective Field Theories (EFTs) in cosmology. In particular, I show how to generalize the EFT of the …
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Études on fuzzy geometry and cosmology
… BPS and non-BPS solutions of the CJPN nonlinear sigma model on the noncommutative plane in some detail and show among other things that a class of its solitonic excitations may be built from bound states of noncommutative scalar solitons. We then go on to construct a fuzzy extension of the …
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On Quantum Simulators and Adiabatic Quantum Algorithms
… simulate the quantum dynamics of the Ising model and the O(3) nonlinear sigma model.
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Moduli Space of (0,2) Conformal Field Theories
… a compact K\"ahler base manifold. While such models are naturally obtained as phases in a gauged linear sigma model (GLSM), our construction is independent of such an embedding. We discuss the general properties of such theories and present a technique to study the massless spectrum of the …
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Some Aspects of Fluctuation Driven Phenomena
… critical dynamics of the O(3) nonlinear sigma model describing isotropic antiferromagnets with a non-conserved order parameter reversibly coupled to the conserved total magnetization. We find that in equilibrium, the dynamics is well-separated from the statics and the static response …
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The geometry and representation theory of superconformal quantum mechanics
… aspects of the quantum mechanics of nonlinear $\sigma$-models with superconformal invariance. The connection between the differential geometry of the target manifold and symmetries of the quantum mechanics is explored, resulting in a classification of spaces admitting $\mathcal{N}=(n,n)$ …
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