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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 8 of 8 for “"Hubbard-Modell"”.
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Magnetische Phasenübergänge im Hubbard-Modell mit Frustration
… metal-insulator transition in the Hubbard Model with frustration are discussed. Spin systems are called frustrated if there are couplings between sites that hamper the transition to an antiferromagnetically ordered ground state. In the Hubbard Model this can be achieved by a proper …
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Instabilitäten und spontane Symmetriebrechung in zweidimensionalen Fermisystemen
… essential aspects of these physical systems. The Hubbard model in two dimensions plays an important role in this context. The present thesis examines instabilities and possible symmetry broken phases of the two-dimensional repulsive Hubbard model with the help of numeric and semi analytic methods. …
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Spectral properties of strongly correlated electron systems
… properties at zero temperature within the Hubbard an three-band-Hubbard model for the superconducting copper oxides. Based on the recently proposed self-energy functional approach (SFA) [M.Potthoff, Eur. Phys. J. B 32 429 (2003)], we present an extension of the cluster-perturbation theory …
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All-electron GW calculations for perovskite transition metal oxides
… thesis focuses on the question how accurately a Hubbard model can reproduce the spectrum of a subspace of the full Hilbert space, as this kind of model allows to gain insight into the electronic structure of materials even if first-principles approaches are not applicable. A simple test system is …