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Showing 1 to 18 of 18 for “"bethe-salpeter"”.
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Normalization of Bethe-Salpeter Amplitudes
Made available in DSpace on 2015-05-12T21:41:42Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 6801856.PDF: 1764345 bytes, checksum: 279aa456f956ad81e315e32a94735dab (MD5) Previous issue date: 1967
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A model for pion-nucleon scattering based on the Bethe-Salpeter equation.
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 1968
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Improvement of the dielectric screening model in the Bethe-Salpeter equation approach: From static screening approximation to dynamical screening model
The student, Xiao Zhang, accepted the attached license on 2019-11-14 at 15:16.
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Perturbation theory of two particle bound states in QED for particles of spin ��� 1
In this paper we present a generalization of Salpeter's approach to solving the Bethe-Salpeter equation for the hydrogen atom to the case of any two particles of spin ≤ 1. In order to preserve the same general form of Salpeter's scheme the Kemmer-Duffin equations are used to describe the spin 1 or …
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Optical Response Of Finite And Extended Systems
… of jellium with and without a gap, using the Bethe-Salpeter equation. We only considered diagrams where the electron hole pair interact, via a statically screened Coulomb interaction, and we summed these diagrams to infinite order. First we coupled forward- and backward going electron-hole …
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Field Theoretic Models of Deep Inelastic Lepton-Nucleon Scattering
… meson theory. 4. The leading part of the Bethe-Salpeter for the Compton amplitude in the neutral vector meson ladder model is closely related to Jackiw's Bethe-Salpeter equation for the electromagnetic vertex. (MT<sub>μ</sub><sup>μ</sup> which is the trace of the spin-averaged virtual …
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Normalization of Bethe-Saltpeter amplitudes
… derivations of the normalization condition for Bethe-Salpeter (bound state) amplitudes are presented. The first derivation is based on charge conservation. The normalization condition obtained is independent of the total charge of the system and, in principle, could be applied to a neutral …
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Lorentz contraction effects in the electromagnetic form factors of relativistic two-body bound systems
… the two-body bound system is calculated from the Bethe-Salpeter equation and inserted into form factor expressions for scalar and vector photons. Even in the Breit frame, the charge density is distorted due to relativistic effects. The resulting form factor is compared to a static form factor …
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First principles calculations on ZnO non-equilibrium phase
… experimental band gap. Further, by solving the Bethe-Salpeter Equation, excitonic effect has been included and the exact optical spectrum for both structure has been obtained. We have found a large optical anisotropy for BN structure. Lastly we calculated the exciton binding energy for the BN …
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Tddft Derivative Couplings And Other Topics In Quantum Chemistry
… electron attachment/detachment energy, and the Bethe-Salpeter equation, which is used to obtain the electron excitation energies of a system.
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An equation for meson states in the quark model and its application to a meson bootstrap
… equation for meson states is derived from the Bethe-Salpeter equation under the conditions of the quark model. The equation is shown to imply mass relations of the form K* 2 - P2 = K2 2 - 1£ • The equation is used to attempt bootstrap calculations of the vector and pseudo-scalar meson …
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Static and dynamic properties of the pion from continuum modelling of strong QCD
… equation (SDE) and pseudoscalar meson Bethe-Salpeter equation (BSE) at and beyond the rainbow-ladder truncation level of this system of equations. We solve this coupled system of integral equations using a phenomenological model for the dressed gluon propagator in Landau gauge as input. …
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Zwei-Fermionen-Systeme in der relativistischen Schrödinger-Theorie
… Für zwei Teilchen existiert zwar die Bethe-Salpeter-Gleichung, die jedoch diverse Interpretationsprobleme aufwirft; für mehr als zwei gebundene Teilchen gibt es noch keine ausgereiften Ansätze. Für gebundene Mehrteilchenprobleme werden deshalb Energiewerte gewöhnlich zuerst …
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Ab initio modelling of photoinduced electron dynamics in nanostructures
… those obtained by time-dependent DFT and the Bethe-Salpeter equation. Again, the two approaches are in good, qualitative agreement.The thesis is left open as a starting point towards investigating the TMD-MNP structures, as well as stating the limitations of the PEOM method and suggesting …
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Computational investigation on polycyclic aromatic hydrocarbons in the molecular and solid phases
… theory calculations within the GW and Bethe-Salpeter equation for- malisms. In addition, for the crystal structures of PNT and HTP we perfomed DFT-based calculations using a pseudopotentials+plane- waves formalism and adopting the PBE exchange-correlation func- tional empirically …
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Exciton Dynamics and Anisotropy in 2D Metal Organochalcogenolate Semiconductors
… spectroscopy, combined with the GW plus Bethe-Salpeter equation calculations, we reveal multiple low-lying excitons with in-plane anisotropy in AgSePh and AgTePh. This showcases the richness of excitonic physics in these materials, which arises from their low-symmetry crystal structures. …
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Tunable Electronic Excitations in Hybrid Organic-Inorganic Materials: Ground-State and Many-Body Perturbation Approaches
… of the thesis, an all-electron implementation of Bethe-Salpeter equation (BSE) approach based on the $GW$ approximation is developed using numeric atom centered orbital basis sets, with the aim of developing first steps to a formal many-body theory treatment of neutral excitations, which goes …
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Novel materials, computational spectroscopy, and multiscale simulation in nanoscale photovoltaics
… density functional theory (DFT) and the GW-Bethe-Salpeter approach. Proof-of-concept PV devices were fabricated and tested within our group and in collaboration with other experimental research groups. The two material families studied in this thesis include carbon based materials (both in …