Karlsruhe 2011 – scientific programme
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GR: Fachverband Gravitation und Relativitätstheorie
GR 8: Kosmologie
GR 8.5: Talk
Thursday, March 31, 2011, 09:50–10:10, 20.40: 101
Inflationary Correlation Functions without Infrared Divergencies — •Mischa Gerstenlauer — Institut für Theoretische Physik, Heidelberg
Inflationary correlation functions are potentially affected by infrared divergences. For example, the two-point correlator of curvature perturbations at momentum k receives corrections ∼ln(kL), where L is the size of the region in which the measurement is performed. We define infrared-safe correlation functions which have no sensitivity to the size L of the box used for the observation. The conventional correlators with their familiar log-enhanced corrections (both from scalar and tensor long-wavelength modes) are easily recovered from our IR-safe correlation functions. Among other examples, we illustrate this by calculating the corrections to the non-Gaussianity parameter fNL coming from long-wavelength tensor modes. In our approach, the IR corrections automatically emerge in a resummed, all-orders form. For the scalar corrections, the resulting all-orders expression can be evaluated explicitly.