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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 94 for “"Feynman"”.
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An Introduction To Hellmann-feynman Theory
The Hellmann-Feynman theorem is presented together with certain allied theorems. The origin of the Hellmann-Feynman theorem in quantum physical chemistry is described. The theorem is stated with proof and with discussion of applicability and reliability. Some adaptations of the theorem to the study …
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On Different Parametrizations of Feynman Integrals
… insights on the mathematical structures of Feynman integrals.</p> <p>We start by presenting phenomenological calculations relevant for the experimental analyses at the Large Hadron Collider. We use the resummation of soft gluon emission corrections to study the associated production of a top …
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Feynman integrals, hypergeometric functions and nested sums
In this thesis, we present analytical expansion results of some single-mass-scale four-loop vacuum integrals in 3 and 4 dimensions. After finding hypergeometric representations with half-integer coefficients, we use algorithms which we implemented in FORM to expand these in terms of nested sums.
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Feynman Diagram Models of Daughter Regge Trajectories
The Van Hove model of Regge poles is used to study daughter trajectories of bosons in scalar meson-scalar meson scattering and of fermions in backward pion-nucleon scattering. Both the simple model with bare propagators and a generalized model that includes propagator self-energy insertions are …
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Feynman-Kac Numerical Techniques for Stochastic Optimal Control
… differential equations (FBSDEs) appearing in the Feynman-Kac representation of the value function in stochastic optimal control (SOC) problems. First, we propose a novel characterization of FBSDE estimators as either on-policy or off-policy, highlighting the intuition for these techniques that the …
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Feynman-Dyson perturbation theory applied to model linear polyenes
In the work described in this thesis, the Feynman-Dyson perturbation theory, developed from quantum field theory, was employed in semiempirical calculations on trans - polyacetylene. A variety of soliton-like excited states of the molecule were studied by the PPP-UHF-RPA method. The results of this …
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On Switching Diffusions: The Feynman-Kac Formula And Near-Optimal Controls
… contexts. First, we consider the so-called Feynman-Kac formula(s) for switching diffusions. These formulas provide stochastic representations for solutions of certain weakly coupled elliptical systems of partial differential equations. The formulas are verified for the boundary value …
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On the Estimates of the Density of Feynman-Kac Semigroups of Alpha-Stable-Like Processes and the Purely Discontinuous Girsanov Transform of Alpha-Stable-Like Processes
… we study two-sided estimates of the density of Feynman-Kac semigroups of alpha-stable-like processes and two-sided estimates of the density of purely discontinuous Girsanov transforms of alpha-stable-like processes. Without assuming symmetry of the processes, under certain conditions, we show …
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Canonical quantization and quantum chromodynamics in a cavity
… Based on this formalism, we calculate, in the Feynman gauge, all non-divergent Feynman diagrams of second order in the strong coupling constant g. Explicit values of the matrix elements are given for low-lying quark and gluon cavity modes.
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Two-gluon exchange graphs in cavity QCD to order αs2
… which are second order in as. Two distinct Feynman diagrams exist, of which each consists of twenty-four timeordered diagrams. All the possible time-ordered diagrams are calculated here. A similar calculation of only the first six time-ordered diagrams has been performed by Stoddart et …
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Perturbative Quantum Gravity and Yang-Mills Theories in de Sitter Spacetime
… 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 the physical equivalence of covariant Wightman graviton two-point function with the …
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Quasicentroid Molecular Dynamics
… of coordinates subject to thermally averaged Feynman path fluctuations (“the mean field”). This theory approximates the dynamics of systems at thermal equilibrium that follow quantum Boltzmann statistics and undergo rapid quantum decoherence. As it relies on purely classical mechanics, the …
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Electroweak Calculations In The Presence Of Nonperturbative Qcd Effects
A momentum space Feynman rule is derived for the quark condensate insertion into Feynman amplitudes using the quark condensate component of the nonperturbative vacuum expectation value of the two nonlocal normal ordered quark fields. The lowest-order quark condensate component of the QCD …
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Finite-temperature quantum field theory and the structure functions of the nucleon
… in the propagation of particles when considering Feynman diagrams containing internal lines in next-to-leading-order calculations. These features are incorporated through the use of Fermi-Dirac and Bose-Einstein distributions for quarks and gluons, respectively. Stimulated emission factors for …
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Production of omega and phi mesons by 193 GeV/c pions and 250 GeV/c protons on a beryllium target
… with respect to perpendicular momentum and Feynman-X for both meson types and both beam types are compared. When a simple parton fusion model is used to describe the Feymnan-X distributions the omega appears to be produced predominantly by gluon fusion.
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Some application of Malliavin calculus to SPDE and convergence of densities
… studied in this dissertation. In Chapter 3, a Feynman-Kac formula is established for a stochastic heat equation driven by Gaussian noise which is, with respect to time, a fractional Brownian motion with Hurst parameter H<1/2. To establish such a formula, we introduce and study a nonlinear …
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Intrinsic contractivity for some non-symmetric Lévy processes with non-local operators
… sharp estimates for the eigenfunctions of the Feynman- Kac semigroups of these two types of processes and established their intrinsic contractivities. Our methods are mainly probabilistic and depend essentially on the sharp estimates of heat kernels.
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Application of the relativistic Schrödinger equation to the bootstrap problem
… problem. The forces are computed from the usual Feynman graphs for single particle exchanges. At first, pseudoscalar-pseudoscalarmeson scattering is considered in a multichannel calculation. The vector mesons obtained are recombined with the pseudoscalars, and multichannel vector-pseudoscalar …
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Perturbative quantum chromodynamics in a cavity
… 4th order perturbation theory we calculate the Feynman diagrams corresponding to configuration mixing-and two gluon annihilation. The results are inserted into the MIT bag model and compared with hadron spectra.
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