Seminars and Journal Clubs

Dilaton Inflation and the Dynamical Origin of the Planck Scale

by Kai Schmitz


Classical scale invariance represents a promising framework for model building beyond the Standard Model. However, once coupled to gravity, any scale-invariant microscopic model requires an explanation for the origin of the Planck scale. In this talk, I will present a minimal example for such a mechanism and show how the Planck mass may be dynamically generated in a strongly coupled gauge sector. I will consider the case of hidden SU(N) gauge interactions that link the Planck scale to the condensation of a scalar bilinear operator that is nonminimally coupled to curvature. The effective theory at energies below the Planck mass contains two scalar fields: the pseudo-Nambu-Goldstone boson of spontaneously broken scale invariance (the dilaton) and a gravitational scalar degree of freedom that originates from the R^2 term in the effective action (the scalaron). I will discuss the effective potential for the coupled dilaton-scalaron system at one-loop order and demonstrate that it can be used to successfully realize a stage of slow-roll inflation in the early Universe. Remarkably enough, the resulting predictions for the primordial scalar power spectrum include and extend those of standard R^2 inflation. For comparatively small coupling constants in the gravitational sector, one obtains a spectral index n_s ~ 0.97 and a tensor-to-scalar ratio as large as r ~ 0.08. This talk is based on work in progress in collaboration with Jisuke Kubo, Manfred Lindner und Masatoshi Yamada

Your browser is out of date!

Update your browser to view this website correctly. Update my browser now