Determine cosmological predictions of CQ scalar–tensor gravity

Investigate the cosmological-scale predictions of classical–quantum scalar–tensor gravity models, including decoherence of quantum spacetimes and diffusion in the effective Newtonian constant, and assess their implications for inflation, large-scale structure, and precision cosmology.

Background

The model suggests generic low-energy phenomena (decoherence tied to curvature and diffusion in the scalar field), and similar behaviors may arise in broader CQ Horndeski-type couplings. The paper notes potential relevance to cosmology but defers detailed analysis.

A systematic cosmological study would test whether CQ scalar–tensor gravity yields distinct observational signatures, constraints, or resolutions of known tensions compared to GR and conventional modified gravity.

References

What do such theories predict on cosmological scales? We leave these as open questions for future work.

— Quantum gravity with dynamical wave-function collapse via a classical scalar field  (2402.17024 - Weller-Davies, 2024) in Section 7: Discussion

The explicit derivation of these additional predictions is left to future work.

— Spectral Suppression of Asymptotic States in Supersymmetric QFT on de Sitter Backgrounds  (2609.10814 - Bellucci et al., 9 Sep 2026) in Section 4, subsection “Falsifiable predictions of the NA framework”

Whether such stochastic dynamics has observable cosmological consequences remains an interesting question for future investigation.

— Statistical Symmetry Breaking and Emergent Colored Noise in a Stochastic Scalar-Doublet Field Theory  (2609.03312 - Wang, 3 Sep 2026) in Section 1, Introduction

Whether the competition between classical and quantum contributions found here admits a genuine cosmological interpretation in a dynamical setting, where the geometry evolves self-consistently, remains an open question.

— Semiclassical Cosmological Constant in Anti-de Sitter and de Sitter Spacetimes  (2610.09436 - Mamani-Leqque, 7 Oct 2026) in Final remark following Section 6 (Conclusions)