Implication of the swampland distance conjecture on the Cohen-Kaplan-Nelson bound in de Sitter space

TL;DR

This paper explores how the swampland distance conjecture impacts the Cohen-Kaplan-Nelson bound in de Sitter space, revealing constraints on slow-roll inflation and the conditions preventing eternal inflation.

Contribution

It analyzes the interplay between the swampland conjecture and the CKN bound in de Sitter space, deriving bounds on slow-roll parameters.

Findings

The CKN bound constrains matter distribution size in de Sitter space.

The analysis yields a bound on the slow-roll parameter.

The results suggest conditions that forbid eternal inflation.

Abstract

The Cohen-Kaplan-Nelson (CKN) bound formulates the condition that black hole is not produced by the low energy effective field theory dynamics. In de Sitter space it also constrains the maximal size of the matter distribution to be smaller than the cosmological horizon determined by black hole. On the other hand, the swampland distance conjecture (SDC) predicts that de Sitter space becomes unstable by the descent of the low energy degrees of freedom from UV. This results in the rapid increase in the energy inside the cosmological horizon, the distribution of which can be constrained by the CKN bound. We study the CKN bound in de Sitter space in detail and point out that when compared with the slow-roll in the inflation, the bound on the slow-roll parameter which forbids the eternal inflation is obtained.