Bounds on Tensor wave and Twisted Inflation

TL;DR

This paper investigates bounds on tensor waves in twisted inflation models involving wrapped D-branes, revealing differences from traditional models and highlighting the D8-brane as particularly promising for cosmology.

Contribution

It derives bounds on tensor waves in twisted inflation, showing the upper bound differs from Type IIB models and identifying the D8-brane as especially relevant.

Findings

Lower bound similar to Type IIB models

Upper bound significantly different in twisted models

Wrapped D8-brane is cosmologically attractive

Abstract

We study the bounds on tensor wave in a class of twisted inflation models where $D(4+2k)$-branes are wrapped on cycles in the compact manifold and wrap the KK-direction in the corresponding effective field theory. While the lower bound is found to be analogous to that in Type IIB models of brane inflation, the upper bound turns out to be significantly different. This is argued for a range of values for the parameter $g_s M$ satisfying the self-consistency relation and the WMAP data. Further, we observe that the wrapped $D8$-brane appears to be the most attractive from a cosmological perspective.