A New de Sitter Solution with a Weakly Warped Deformed Conifold

Abstract

We revisit moduli stabilisation for type IIB flux compactifications that include a warped throat region corresponding to a warped deformed conifold, with an anti-D3-brane sitting at its tip. The warping induces a coupling between the conifold's deformation modulus and the bulk volume modulus in the Kähler potential. Previous works have studied the scalar potential assuming a strong warping such that this coupling term dominates, and found that the anti-D3-brane uplift may destabilise the conifold modulus and/or volume modulus, unless flux numbers within the throat are large, which makes tadpole cancellation a challenge. We explore the regime of parameter space corresponding to a weakly-but-still warped throat, such that the coupling between the conifold and volume moduli is subdominant. We thus discover a new metastable de Sitter solution within the four-dimensional effective field theory. We discuss the position of this de Sitter vacuum in the string theory landscape and swampland.

Stringy Bubbles Solve de Sitter Troubles

“…Constructing solutions in string theory with these features has been argued to be notoriously hard if not impossible: see [3][4][5] for recent comprehensive reviews. However, recent work [6,7] and [8], as well as [9], turn out to correspond naturally with a stringy cosmic dS-brane toy-model [10][11][12][13][14] which we furthermore connect with a generalization of the proposal that allows for more general spacetime varying string vacua [15].…”

“…In this sense, this class of toy models also describe nearly singular spacetimes, much as those studied in Ref. [8,[33][34][35] -except that the background configurations are here restricted to a discretuum by the SL(2; Z)-monodromy. Indeed, the axilaton, τ (ωθ), varies over Y 2 ⊥ including values that oscillate about g s e Φ = O(1), even a few orders of magnitude!…”

“…Here, the complex structure deformation of the conifold singularity and the relative size of associated vanishing cycles, the D3-brane contributions, and the metric warping all affect the target spacetime physics. A detailed examination of such a nearly singular warped direct product compactification scenario finds a fine-tuned regime within the parameter space in which the multiple competing contributions can be shown to induce a metastable dS metric in the non-compact spacetime factor [8]; see however also the review [35] and the references therein. Note that the vanishing cycles in the deformation-singularizing complex, compact Calabi-Yau 3-folds are real three-dimensional subspaces, matching in dimension the "probing" D3-branes.…”

“…Mirror symmetry guarantees that the same type of phenomenon occurs near the conifold singularity on the Kähler (or symplectic) structure side, as is the case with very small relative sizes of so-called exceptional sets 4 in a Calabi-Yau 3-fold compactification. As with the near singularization by complex structure deformation [8], one again expects a detailed balance of various contributing factors. While exact calculations on this, Kähler, side are much harder in general and not amenable to explicit probing and direct computation, such mirror-symmetric configurations are qualitatively identical.…”

“…The main ideas are the following: (1) Both the AdS-decaying [6,7] and the so called "axilaton" [10][11][12][13][14] scenarios are near a singularity: They are "resolutions/smoothings" of a singular/critical model, and so are inherently non-perturbative [8]. As such, a closer examination can (and does) find special configurations in which the various competing contributions do allow for a four-dimensional (sub-)spacetime of the desired dS geometry.…”