Concept record · Atlas v1.2.0
String swampland
ConjectureWhat the term means here
The proposed set of effective field theories that look internally consistent as low-energy theories but admit no ultraviolet completion in quantum gravity. The swampland program tries to characterize that set with conjectured criteria.
Why it matters to this question
If the criteria are right, they constrain what any quantum theory of gravity permits, without needing an explicit construction. The de Sitter question then becomes: are the candidate de Sitter constructions in the landscape, or in the swampland?
What this does not establish
The swampland criteria are conjectures, motivated by patterns in known constructions and by black-hole and thermodynamic arguments. They are not theorems, and a construction being argued into the swampland is a claim about the conjectures as much as about the construction.
Claims bearing on this concept · 5
- ds-002
Whether string/M-theory admits stable or metastable de Sitter vacua remains an open question, and there is no community consensus.
- ds-007
The de Sitter swampland conjecture proposes that scalar potentials in consistent quantum-gravity effective theories obey a gradient bound |∇V| ≥ c·V, with c of order one.
- ds-009
The Trans-Planckian Censorship Conjecture proposes that sub-Planckian fluctuations never cross the Hubble horizon and freeze, which bounds the lifetime of a de Sitter phase.
- ds-010
If metastable de Sitter vacua are excluded, dark energy would have to be dynamical — a rolling scalar field rather than a constant.
- ds-011
The Dark Dimension scenario ties the dark-energy scale to a Kaluza-Klein scale via the AdS distance conjecture, predicting a single extra dimension of roughly micron size.
Sources used for this record · 4
- The original de Sitter swampland conjecturearXiv:1806.08362
- The refined form of the de Sitter conjecturearXiv:1810.05506
- The AdS distance conjecturearXiv:1906.05225
- What if string theory has no de Sitter vacua?arXiv:1804.01120