Distance and de Sitter conjectures on the Swampland

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.

“…We have provided evidence, in an arguably simpler way than that of [], for the exponential decay of the scalar potential. Let us now assume that indeed

V false(ϕ false) < e^{- a ϕ}

as one approaches the boundary of field space,

ϕ \to \infty

.…”

Section: A Potential Loopholementioning

confidence: 96%

Section: A Simplified Derivationmentioning

confidence: 99%

n (ϕ)

in the exponential growth of species,

N (ϕ) = n (ϕ) exp (c ϕ)

, below a certain cutoff (which must also depend on ϕ and the definition of which is not a priori obvious).…”

Section: A Potential Loopholementioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

See 2 more Smart Citations

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

Hebecker

Wrase

2018

“…The purpose of this short note is to deepen this connection with [] including its more recent refined version . The touching point is that both proposals exclude self‐reproduction regimes and this results in natural similarities in the constraints that they impose on scalar potentials.…”

mentioning

confidence: 99%

Quantum Breaking Bound on de Sitter and Swampland

Dvali

Gómez

Zell

2018

107

109

Quantum consistency suggests that any de Sitter patch that lasts a number of Hubble times that exceeds its Gibbons‐Hawking entropy divided by the number of light particle species suffers an effect of quantum breaking. Inclusion of other interactions makes the quantum break‐time shorter. The requirement that this must not happen puts severe constraints on scalar potentials, essentially suppressing the self‐reproduction regimes. In particular, it eliminates both local and global minima with positive energy densities and imposes a general upper bound on the number of e‐foldings in any given Hubble patch. Consequently, maxima and other tachyonic directions must be curved stronger than the corresponding Hubble parameter. We show that the key relations of the recently‐proposed de Sitter swampland conjecture follow from the de Sitter quantum breaking bound. We give a general derivation and also illustrate this on a concrete example of D‐brane inflation. We can say that string theory as a consistent theory of quantum gravity nullifies a positive vacuum energy in self‐defense against quantum breaking.

The Tension between 10D Supergravity and dS Uplifts

Gautason

Hemelryck

Riet

2018

116

203

We elaborate on the recent work of Moritz et al. where it is argued that anti‐brane uplifting in KKLT models never leads to dS vacua. This is due to flattening effects in the effective potential found when treating the gaugino condensate energy momentum in ten‐dimensional supergravity. We point out that the Silverstein‐Saltman uplift, which effectively dissolves the anti‐brane in 3‐form fluxes, is a conceptually simpler setting in which flattening effects can be present, without requiring assumptions about UV/IR mixings. Along the way we revise and improve on the arguments of Moritz et al. and discuss various subleties when studying gaugino condensates from a ten‐dimensional point‐of‐view. In particular, the “no dS” argument is slightly weaker and we emphasize a technical loophole that might allow dS vacua. Finally we suggest that AdS vacua which are parametrically controlled from these flattening effects belong to the Swampland. We comment on the relation with the recent refined dS Swampland inequalities.