Major Conjectures and Cosmological Tests R: Cosmological Interpretation of the String Landscape and Swampland Conjectures

The”Landscape” and ”Swampland”conjectures in string theory have long residedin the metaphysical realm of theoretical physics. This paper proposes a physicalframework based on the principles of information and self-referential consistency,aiming to transform these concepts into experimentally falsifiable cosmological hypotheses. We argue that the physically realizable vacua within the landscape mustsatisfy dualities compatible with the universe’s self-referential information structure,which will leave imprints on primordial cosmological perturbations; simultaneously,the constraints of the Swampland conjecture can be re-interpreted as necessary conditions for ensuring the self-consistency between low-energy effective theories andultraviolet-complete quantum gravity, thereby yielding explicit predictions for darkenergy dynamics. This paper derives two independent, quantitative cosmologicalobservational predictions: 1) A local-type non-Gaussianity parameter with a specific negative signature, fNL = −5.2 ± 1.5, in the cosmic microwave backgroundradiation; 2) An evolutionary turning point in the dark energy equation-of-stateparameter w(z) around redshift zc = 1.8 ± 0.3. These predictions can be testedby next-generation astronomical observational facilities such as DESI, Euclid, andCMB-S4, opening a new pathway for constraining the fundamental structure ofstring theory through cosmological observations.