If metastable de Sitter vacua are excluded, dark energy would have to be dynamical — a rolling scalar field rather than a constant.

If metastable de Sitter vacua are excluded, dark energy would have to be dynamical — a rolling scalar field rather than a constant.

Why it is stated this way

Quintessence is the standard fallback if the swampland position is correct, and it is where the conjectures make contact with data that can actually be measured.

Scope and limitations

This is a conditional claim, not a claim that dark energy is dynamical. Bounds near w = −1 constrain rolling models; one 2023 reanalysis in the source set finds newer data allows slightly more freedom in the criteria rather than tightening the tension, while raising a separate fine-tuning problem from constraints on moduli-electromagnetic couplings.

Sources

• Cosmological implications of the swampland conjectures ↗ · Agrawal, Obied, Steinhardt, Vafa · arXiv:1806.09718
• Equation-of-state bounds on swampland quintessence ↗ · Heisenberg, Bartelmann, Brandenberger, Refregier · arXiv:1808.02877
• News from the Swampland — constraining string theory with astrophysics and cosmology ↗ · Schöneberg, Vacher, Dias, Carvalho, Martins · arXiv:2307.15060 · JCAP 2023(10), 039; doi:10.1088/1475-7516/2023/10/039

Related atlas concepts

Cosmological constantObservational cosmologyde Sitter spacetimeString swampland