(In)stability of de Sitter vacuum in light of distance conjecture and emergence proposal

Infinite distance limits in the moduli space of a quantum gravity theory are characterized by having infinite towers of states becoming light, as dictated by the Distance Conjecture in the Swampland program. These towers imply a drastic breakdown in the perturbative regimes of the effective field theory at a quantum gravity cut-off scale known as the species scale. In this work, we find a universal pattern satisfied in all known infinite distance limits of string theory compactifications, which relates the variation in field space of the mass of the tower and the species scale: $$ \frac{\overrightarrow{\nabla}m}{m}\cdotp \frac{\overrightarrow{\nabla}{\Lambda}_{\textrm{sp}}}{\Lambda_{\textrm{sp}}}=\frac{1}{d-2} $$ ∇ → m m · ∇ → Λ sp Λ sp = 1 d − 2 in d spacetime dimensions. This implies a more precise definition of the Distance conjecture and sharp bounds for the exponential decay rates. We provide plethora of evidence in string theory in diverse dimensions and with different levels of supersymmetry, and identify some sufficient conditions that allow the pattern to hold from a bottom-up perspective.

Section: The Emergence Proposalmentioning

confidence: 95%

Stringy evidence for a universal pattern at infinite distance

Castellano,

Ruiz,

Valenzuela

2024

Entropy bounds and the species scale distance conjecture

Calderón-Infante,

Castellano,

Herráez

et al. 2024

The Swampland Distance Conjecture (SDC) states that, as we move towards an infinite distance point in moduli space, a tower of states becomes exponentially light with the geodesic distance in any consistent theory of Quantum Gravity. Although this fact has been tested in large sets of examples, it is fair to say that a bottom-up justification based on fundamental Quantum Gravity principles that explains both the geodesic requirement and the exponential behavior has been missing so far. In the present paper we address this issue by making use of the Covariant Entropy Bound as applied to the EFT. When applied to backgrounds of the Dynamical Cobordism type in theories with a moduli space, we are able to recover these main features of the SDC. Moreover, this naturally leads to universal lower and upper bounds on the ‘decay rate’ parameter λsp of the species scale, that we propose as a convex hull condition under the name of Species Scale Distance Conjecture (SSDC). This is in contrast to already proposed universal bounds, that apply to the SDC parameter of the lightest tower. We also extend the analysis to the case in which asymptotically exponential potentials are present, finding a nice interplay with the asymptotic de Sitter conjecture. To test the SSDC, we study the convex hull that encodes the large-moduli dependence of the species scale. In this way, we show that the SSDC is the strongest bound on the species scale exponential rate which is preserved under dimensional reduction and we verify it in M-theory toroidal compactifications.

On the particle picture of Emergence

Hattab,

Palti

2024

The Emergence Proposal is the idea that all kinetic terms for fields in quantum gravity are emergent in the infrared from integrating out towers of states. It predicts that in a supersymmetric string theory context, the tree-level prepotential terms can be recovered precisely by integrating out a tower of non-perturbative states. In this note we present a new perspective, and associated quantitative evidence, for this proposal. We argue that the tree-level kinetic terms arise from integrating out the ultraviolet physics of each of the states in the tower. This ultraviolet physics is associated to extended objects, and cannot be captured by a standard particle Schwinger integral. Instead, we argue that it should be captured by a Schwinger-like integral where the proper time is analytically continued, and a contour is taken around the origin. This maps to certain integral representations for the moduli space periods, and indeed one recovers the tree-level prepotential exactly. This interpretation suggests that the ultraviolet physics which gives the leading contribution to the prepotential is localised on point intersections of the extended objects. We also argue that over special loci in moduli space there can exist a particle picture of the states, and an associated simple particle Schwinger integral, which leads to the full tree-level prepotential. These are loci with special degenerations, such as the singular limit of the resolved conifold.