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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Lokalisierung für korrelierte Anderson Modelle

Tautenhahn, Martin 01 October 2007 (has links) (PDF)
Im Fokus dieser Diplomarbeit steht ein korreliertes Anderson Modell. Unser Modell beschreibt kurzreichweitige Einzelplatzpotentiale, wobei negative Korrelationen zugelassen werden. Für dieses korrelierte Modell wird mittels der fraktionalen Momentenmethode im Falle genügend großer Unordnung exponentieller Abfall der Greenschen Funktion bewiesen. Anschließend wird daraus für den nicht korrelierten Spezialfall Anderson Lokalisierung bewiesen. / This thesis (diploma) is devoted to a correlated Anderson model. Our model describes short range single site potentials, whereby negative correlations become certified. For this correlated model exponential decay of the Greens' function is proven in the case sufficient large disorder according to the fractional moment method. Subsequently, we prove Anderson localization for the not correlated special case.
2

Basis functions meet spatiospectral localization: studies in spherical coordinates

Huang, Xinpeng 26 November 2024 (has links)
In the presented work, we study several basis systems satisfying certain spatial/spectral localization conditions on the unit sphere and the ball embedded in Euclidean space of dimension $d\geq2$. For the spherical setup, we investigate some properties of the Hardy-Hodge decomposition for locally supported fields, and propose a multi-scale basis system that is suitable for modeling the Hardy components of such spherical vector fields and allows a simple mapping between the Hardy spaces. In the case of the solid ball, we revisit the Slepian spatiospectral concentration problems for the spherical Fourier-Jacobi, spherical Fourier-Bessel, as well as the multivariate algebraic polynomial systems. We investigate the bimodal distribution phenomena of the eigenvalues of concentration operators and give an asymptotic characterization of the Shannon number for these setups, which lay a foundation for the utilization of associated Slepian bases and localized spectral analysis.
3

Lokalisierung für korrelierte Anderson Modelle

Tautenhahn, Martin 13 August 2007 (has links)
Im Fokus dieser Diplomarbeit steht ein korreliertes Anderson Modell. Unser Modell beschreibt kurzreichweitige Einzelplatzpotentiale, wobei negative Korrelationen zugelassen werden. Für dieses korrelierte Modell wird mittels der fraktionalen Momentenmethode im Falle genügend großer Unordnung exponentieller Abfall der Greenschen Funktion bewiesen. Anschließend wird daraus für den nicht korrelierten Spezialfall Anderson Lokalisierung bewiesen. / This thesis (diploma) is devoted to a correlated Anderson model. Our model describes short range single site potentials, whereby negative correlations become certified. For this correlated model exponential decay of the Greens' function is proven in the case sufficient large disorder according to the fractional moment method. Subsequently, we prove Anderson localization for the not correlated special case.

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