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 300 for “"perturbative"”.
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Aspects of Non-Perturbative Renormalization
… of some key issues regarding the non-perturbative renormalization of the periodic scalar field theories. As an example of the non-perturbative methods, we use the differential renormalization group approach, particularly the Wegner-Houghton and the Polchinski renormalization group …
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Perturbative QCD in exclusive processes
… to operational status. The sensitivity of perturbative QCD predictions for the nucleon form factors, ψ → pp̅, and 𝛾𝛾 → pp̅, to the theoretical uncertainties of the nucleon wave function and the form of the running coupling constant is investigated. A new prediction for the cross-section for …
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Perturbative and non perturbative effects in the Standard Model and orbifolded ADS/CFT based theories
We study some perturbative and nonperturbative effects in the framework of the Standard Model of particle physics. In particular we consider the time dependence of the Higgs vacuum expectation value given by the dynamics of the StandardModel and study the non-adiabatic production of both bosons and …
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HIGH ENERGY RESUMMATION IN PERTURBATIVE QCD
… which is present at any fixed order in the perturbative expansion starting at NNLO.
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Perturbative calculations and the top quark
Submitted by Elizabeth Kent (eckent2@illinois.edu) on 2012-05-17T17:34:22Z No. of bitstreams: 1 1998_Smith.pdf: 1562557 bytes, checksum: 155cebb27389d86711a7d7d56bea2899 (MD5)
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Perturbative quantum chromodynamics in a cavity
BRS invariant Quantum Chromodynamics is quantized in a static spherical cavity, subject to the boundary conditions of the MIT group. Using the Gell-Mann and Low theorem and a modified version of Goldstones theorem we formulate perturbation theory. In 4th order perturbation theory we calculate the …
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Collinear divergences and factorization in perturbative QCD
The issue of choosing a factorization scale in perturbative QCD is examined in detail. First a previously defined factorization scheme called the collinear scheme is implemented on Higgs production by bottom quark fusion, and then extended to Higgs production by gluon fusion. After this the issue …
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Worldsheet methods for perturbative quantum field theory
This thesis is divided into two parts. The first part concerns the study of the ambitwistor string and the scattering equations, while the second concerns the interplay of the symmetries of the asymptotic null boundary of Minkowski space, called $\scri$, and scattering amplitudes. The first part …
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Non-perturbative approaches to strongly correlated electron systems
… correlated electron systems requires a non-perturbative analysis because Fermi liquid theory inevitably breaks down due to the strong correlation. In this thesis, we will study two non-perturbative approaches to tackle strongly correlated electronic system: 1.) multi-dimensional bosonization …
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Some non-perturbative results in relativistic field theory
… thesis contains the descriptions of two new non-perturbative results in relativistic field theory. The first part of the thesis describes a transformation which can be used to relate the strong coupling limit of the (theta 4)3 quantum field theory to the weak coupling limit of the same theory. …
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Non-perturbative electron beam characterization with a microwiggler
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.
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Collinear singularities and the factorization scale in perturbative QCD
… and the choice of the factorization scale in perturbative QCD calculations. First, we argue in favor of the use of a bottom-quark distribution function, which sums collinear logarithms, in the calculation of the cross section for Higgs-boson production in association with bottom quarks. As a …
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Beyond the standard model of cosmology : a perturbative approach
This thesis concerns higher order perturbations of the standard model of cosmology. The theme is addressed in two distinct research areas. The first area deals with linear perturbations of Bianchi type I model filled with dust whose flow is irrotational, and which is an analogue to second order …
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Non-perturbative determination of Karsch Coefficients in 2 Colour QCD
… Previous studies determined these coefficients perturbatively however this led to negative values for pressure. Non-perturbative studies have proved difficult due to the computational cost and accuracy required. We attempt to determine these coefficients non-perturbatively and review possible …
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Perturbative Check of the Action and Energy Lattice Sum Rules
… is discussed. The energy sum rule is checked perturbatively up to next-to-leading order and shown to be satisfied with good numerical accuracy. The various contributions to the quark-antiquark potential are analyzed, and the restriction of the expectation value of the sum over all spatial …
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Perturbative Quantum Gravity and Yang-Mills Theories in de Sitter Spacetime
… the quantization of Yang-Mills theories and perturbative quantum gravity in curved spacetime. In the second part we calculate the Feynman propagators of the Faddeev- Popov ghosts for Yang-Mills theories and perturbative quantum gravity in the covariant gauge. In the third part we investigate …
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Flux compactifications of Type II string theories under non-perturbative dualities
… and their transformations under a set of non-perturbative dualities. The dualities are the Type IIA-IIB exchanging T duality, the self-symmetry of Type IIB S duality, the non-trivial combination of the two, U duality, and the generalisation of T duality to include Calabi-Yaus, mirror symmetry. …
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Quark and Gluon Form Factors at Three Loops in Perturbative QCD
… at up to three-loop order within massless perturbative Quantum Chromodynamics by studying the photon-quark-anti-quark vertex and the effective vertex of a Higgs boson and two gluons. We use Feynman diagram methods to derive expressions for the form-factors in terms of tensor loop integrals …
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