De Sitter space constraints on brane tensions and couplings

TL;DR

This paper derives bounds on p-brane tensions in de Sitter space based on Hubble rate and Chern-Simons couplings, supporting the Festina Lente conjecture and analyzing implications for string theory branes and axion interactions.

Contribution

It generalizes the Festina Lente bounds to extended objects like branes and provides a bottom-up approach independent of UV completions.

Findings

D-branes satisfy the derived bounds, supporting the Festina Lente conjecture.

2-brane bounds can be evaded with light axions.

Axion domain walls are not constrained by these bounds.

Abstract

We argue for the existence of bounds on the tensions of $p$-branes in de Sitter space in terms of the Hubble rate and the strength of a class of Chern-Simons-like couplings. The world-volume couplings involve Abelian 1-form gauge fields in the bulk and possibly field strengths intrinsic to the brane. In many cases these couplings are the D-brane Chern-Simons terms present in string theory, while in other cases they are the interactions of axion domain walls with $U(1)$ fields. Our arguments use the same logic and assumptions as the recent Festina Lente proposal (thus utilizing the properties of Nariai de Sitter black holes) and generalize it to extended objects, thereby providing a bottom-up set of constraints independent of any particular UV completion. We compare these bounds to the properties of (wrapped) D-branes in Type II string theory in the weak coupling limit, under the assumption that these properties are not modified significantly in de Sitter constructions. We find that all constraints are satisfied by D-branes, providing further evidence for the Festina Lente conjecture. For the particular case of 2-branes with Chern-Simons interactions we obtain a bound, which however can be evaded if the theory contains a light axion. Similarly, we find the bounds do not apply to axion domain walls due to the presence of the axion.