English

Contracting Cosmologies and the Swampland

High Energy Physics - Theory 2021-11-04 v2 Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Phenomenology

Abstract

We consider the cosmology obtained using scalar fields with a negative potential energy, such as employed to obtain an Ekpyrotic phase of contraction. Applying the covariant entropy bound to the tower of states dictated by the distance conjecture, we find that the relative slope of the potential V/V|V^{\prime}| / |V| is bounded from below by a constant of the order one in Planck units. This is consistent with the requirement to obtain slow Ekpyrotic contraction. We also derive a refined condition on the potential which holds near local minima of a negative potential.

Keywords

Cite

@article{arxiv.2104.00630,
  title  = {Contracting Cosmologies and the Swampland},
  author = {Heliudson Bernardo and Robert Brandenberger},
  journal= {arXiv preprint arXiv:2104.00630},
  year   = {2021}
}

Comments

8 pages, 2 figures; v2: 14 pages, 2 figures; references and comments on conformal diagrams added; matches published version

R2 v1 2026-06-24T00:46:57.922Z