The Asymptotic dS Swampland Conjecture ‐ a Simplified Derivation and a Potential Loophole

Abstract

Recently, arguments for a refined de Sitter conjecture were put forward in [1]. Using the large distance conjecture of [2], the authors provide evidence for this dS conjecture in asymptotic regimes of field space, where the parametric control of string theory becomes arbitrarily good. Their main tool is Bousso's covariant entropy bound.[3] Here, we describe a simpler way to reach a similar conclusion. The argument is based on the fact that the cutoff of an effective theory with gravity decreases as the number of species grows. We then discuss a loophole in this argument and its possible counterpart in the assumptions underlying the entropy‐based derivation. The idea is to consider potentials which, while they remain below an exponentially falling bound, have small oscillations leading locally to relatively flat regions or even to an infinite series of dS minima.

The Swampland: Introduction and Review

“…Indeed, another way to think about this censorship is that the decreasing species scale due to the tower of states induces a consistency bound on the magnitude of the potential. This agrees with the ideas in [].…”

Further Refining the de Sitter Swampland Conjecture

“…One option would then be to start with a concave potential, in agreement with current observational bounds, corresponding to our late universe so far, and branch it later on a decreasing exponential with a steep enough slope, if one wants to avoid a big crunch. On more general grounds, one may still want to have an asymptotic potential going as a with , either because of the Dine‐Seiberg argument, the potential upper bound obtained in [], or the asymptotic exponential decay expressed in and the condition . We now make such a proposal concrete.…”

“…This refined de Sitter conjecture has been tested with various phenomenological models, [14][15][16][17][18][19] and has been discussed in relation to stringy constructions [20][21][22][23][24][25][26][27] or in a more general swampland context. [28][29][30][31] In the present paper, we propose an alternative refined de Sitter conjecture.…”

Quantum Breaking Bound on de Sitter and Swampland

“…We shall illustrate the connection for the key regimes by highlighting similarities of the bounds imposed by the two proposals on unstable extrema and on slow-roll potentials. Some recent discussions of the swampland conjecture can be found in [14][15][16][17][18][19][20][21][22][23].…”