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MP: Theoretische und Mathematische Grundlagen der Physik

MP 7: Integrability and Variational Methods

MP 7.2: Fachvortrag

Mittwoch, 9. März 2005, 12:25–12:45, TU MA141

Higher Orders of Large-D Expansion From Variational Perturbation Theory — •Axel Pelster¹ and Sebastian Brandt² — ¹Fachbereich Physik, Universität Duisburg-Essen, Essen, Germany — ²Department of Physics, Campus Box 1105, Washington University St. Louis, MO 63130-4899, USA

We derive recursively the perturbation series for the ground-state energy of the D-dimensional anharmonic oscillator and resum it using variational perturbation theory. Extrapolating the exponentially-fast converging approximants, we extract the coefficients of the large-D expansion to higher orders. The calculation effort is much smaller than in the standard field-theoretic approach based on the Hubbard-Stratonovich transformation.