Four-Dimensional Null Energy Condition as a Swampland Conjecture

Jul 14, 2021
14 pages
Published in:
  • Phys.Rev.Lett. 127 (2021) 18, 181301
  • Published: Oct 27, 2021
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Abstract: (APS)
We analyze four-dimensional Friedmann-Lemaître-Robertson-Walker cosmologies in type IIB, arising from a M-theory dual, and find that the null energy condition (NEC) has to be obeyed by them (except for the negatively curved case) in order for the M-theory action to have a Wilsonian effective description. However, this does not imply that the M-theory metric has to obey the 11D NEC. Thus, we propose a new swampland conjecture—the 4D NEC is a consistency condition for any theory to have a completion within M theory—with an explicit derivation of it for cosmological backgrounds from a top-down perspective. We briefly discuss the cosmological consequences of such a condition derived from M theory.
Note:
  • 14 pages (including an Appendix); comments welcome; v2: double-columned 8 pages (includes Supplementary Materials), matches published version
  • dimension: 4
  • M-theory: duality
  • null-energy condition
  • background
  • cosmological model