On the cosmological implications of the string Swampland

By P. Agrawal, G. Obied, Paul J. Steinhardt, C. Vafa. Physics Letters B, 2018

569 citations recorded by the source corpus.

Abstract We study constraints imposed by two proposed string Swampland criteria on cosmology. These criteria involve an upper bound on the range traversed by scalar fields as well as a lower bound on | ∇ ϕ V | / V when V > 0 . We find that inflationary models are generically in tension with these two criteria. Applying these same criteria to dark energy in the present epoch, we find that specific quintessence models can satisfy these bounds and, at the same time, satisfy current observational constraints. Assuming the two Swampland criteria are valid, we argue that the universe will undergo a phase transition within a few Hubble times. These criteria sharpen the motivation for future measurements of the tensor-to-scalar ratio r and the dark energy equation of state w, and for tests of the equivalence principle for dark matter.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/7566985a0e04c3d09e1e99880943bfa80d5de947

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Citations in the corpus

New physics in light of the H0 tension: An alternative view (2019, unknown): “[274–278] for cosmological implica-”
Bounds on slow roll and the de Sitter Swampland (2018, background): “Our claims in this paper put the old observations about challenges to constructing de Sitter in string theory [39, 40], like the η-problem, together with the more recent observations about the inability to construct non-tachyonic de Sitter in tree level type II constructions [2], as well as the conj”
Assessing observational constraints on dark energy (2024, methodology): “We note that for each model considered in this work, the Swampland conjectures [18, 21, 22] (thought to be required for a consistent theory of quantum gravity) are satisfied for a substantial range of parameters.”
New physics from the polarized light of the cosmic microwave background (2022, background): “Such a discovery would have a far-reaching consequence for quantum gravity: As Λ > 0 is difficult to realise in quantum gravity 130,131 , a recent ‘Swamp-land’ proposal 132–134 favours a dynamical scalar field as the origin of dark energy 135,136 .”
De Sitter vs Quintessence in String Theory (2018, background): “This picture seems also to be suggested by the recently proposed swampland conjecture which forbids the existence of stable dS solutions.[9] Even if this is still a conjecture not based on any rigorous derivation, it is worth exploring its phenomenological implications.”
The Swampland: Introduction and Review (2019, background): “Following the initial analysis of the cosmological implications of the de Sitter conjecture in [430], there has been significant further work.”