Swampland de Sitter conjecture for late-time dark energy

Prove the Swampland de Sitter conjecture asserting a lower bound on the slope of the potential of a scalar field that dominates the evolution of the late-time universe, thereby excluding a cosmological constant and constraining quintessence dark energy models.

Background

The paper argues that recent DESI observations favor time-dependent dark energy and that, from fundamental theory, a pure cosmological constant is problematic due to the Trans-Planckian Censorship considerations within effective field theory. In the context of string theory, the swampland program imposes constraints on low-energy effective theories consistent with quantum gravity.

Within this program, the Swampland de Sitter conjecture posits a lower bound on the gradient of scalar potentials, which would exclude a cosmological constant and place significant restrictions on quintessence scenarios for dark energy. Establishing or refuting this conjecture is central to determining the viability of various late-time cosmological models in string-theoretic frameworks.