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Four-Dimensional Null Energy Condition as a Swampland Conjecture.

Heliudson Bernardo1, Suddhasattwa Brahma1, Keshav Dasgupta1

  • 1Department of Physics, McGill University, Montréal, Quebec H3A 2T8, Canada.

Physical Review Letters
|November 12, 2021
PubMed
Summary
This summary is machine-generated.

We found that four-dimensional Friedmann-Lemaître-Robertson-Walker cosmologies must obey the null energy condition (NEC) for M-theory consistency. This leads to a new swampland conjecture regarding 4D NEC as a completion condition within M theory.

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Area of Science:

  • String Theory and Cosmology
  • Quantum Field Theory

Background:

  • Analysis of four-dimensional Friedmann-Lemaître-Robertson-Walker cosmologies within type IIB string theory.
  • Investigating M-theory duals and their implications for cosmological models.

Purpose of the Study:

  • To determine the conditions under which cosmological solutions in M-theory have a valid Wilsonian effective description.
  • To propose and derive a new swampland conjecture based on the null energy condition (NEC).

Main Methods:

  • Analyzing four-dimensional Friedmann-Lemaître-Robertson-Walker cosmologies derived from M-theory duals.
  • Applying the principles of Wilsonian effective field theory to cosmological actions.
  • Deriving the conjecture from a top-down perspective for cosmological backgrounds.

Main Results:

  • The null energy condition (NEC) must be obeyed by these cosmologies (except for the negatively curved case) for a Wilsonian effective description.
  • The 11-dimensional M-theory metric is not required to obey the 11D NEC.
  • A new swampland conjecture is proposed: the 4D NEC is a consistency condition for M-theory completion.

Conclusions:

  • The 4D NEC serves as a crucial consistency condition for theories to be completed within M theory.
  • Cosmological consequences of this M-theory derived condition are discussed.
  • This work provides a top-down derivation for a swampland conjecture related to cosmological NEC.