Exploring extra dimensions through inflationary tensor modes

• Main Authors: Sang Hui Im, Hans Peter Nilles, Andreas Trautner
• Format: Article
• Language: English
• Published: SpringerOpen 2018-03-01
• Series: Journal of High Energy Physics
• Subjects: Brane Dynamics in Gauge Theories; Cosmology of Theories beyond the SM; Large Extra Dimensions; Spacetime Singularities
• Online Access: http://link.springer.com/article/10.1007/JHEP03(2018)004

Abstract Predictions of inflationary schemes can be influenced by the presence of extra dimensions. This could be of particular relevance for the spectrum of gravitational waves in models where the extra dimensions provide a brane-world solution to the hierarchy problem. Apart from models of large as well as exponentially warped extra dimensions, we analyze the size of tensor modes in the Linear Dilaton scheme recently revived in the discussion of the “clockwork mechanism”. The results are model dependent, significantly enhanced tensor modes on one side and a suppression on the other. In some cases we are led to a scheme of “remote inflation”, where the expansion is driven by energies at a hidden brane. In all cases where tensor modes are enhanced, the requirement of perturbativity of gravity leads to a stringent upper limit on the allowed Hubble rate during inflation.