2018/06/30 by Prateek Agrawal, Georges Obied, Paul J. Steinhardt +1 · 4 citations
Physics and Astronomy · #Astrophysics #Cosmological model #Cosmology #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Particle physics #Physics #Quantum gravity #Quantum mechanics #Relationship between string theory and quantum field theory #Solar and Space Plasma Dynamics #String (physics) #String phenomenology #String theory #Theoretical physics #astro-ph.CO #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1016/j.physletb.2018.07.040
7 pages, 1 figure; added references, short discussion, minor corrections
arxiv created 2018/07/19 · openalex publication_date 2018/08/06 · arxiv updated 2018/10/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
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 |∇ϕV|/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.