Jena 2013 – scientific programme
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GR: Fachverband Gravitation und Relativitätstheorie
GR 18: Quantenfeldtheorie in gekrümmten Raumzeiten
GR 18.2: Talk
Friday, March 1, 2013, 12:00–12:15, HS 6
On dynamical mass generation in Euclidean de Sitter space — •Paul Moch1,2 and Martin Beneke1,2 — 1Physik Department T31, Technische Universität München — 2Institut für Theoretische Teilchenphysik und Kosmologie, RWTH Aachen University
We consider the perturbative treatment of a minimally coupled, massless, self-interacting scalar field in Euclidean de Sitter space. Generalizing the work of Rajaraman, we obtain the dynamical mass m2∝√λH2 of the scalar for non-vanishing Lagrangian masses and the first perturbative quantum correction in the massless case. We introduce the rules of a systematic perturbative expansion, which treats the zero-mode non-perturbatively, and goes in powers of √λ. The infrared divergences of the massless free field theory are self-regulated by the zero-mode dynamics. Thus, in Euclidean de Sitter space the interacting and massless scalar field is just as well-defined as the massive field. We then show that the dynamical mass can be recovered from the diagrammatic expansion of the self-energy and a consistent solution of the Schwinger-Dyson equation. This requires the summation of a divergent series of loop diagrams of arbitrarily high order. We note that the value of the long-wavelength mode two-point function in Euclidean de Sitter space agrees at leading order with the stochastic treatment in Lorentzian de Sitter space, in any number of dimensions.