English

\"Uber-Gravity and the Cosmological Constant Problem

General Relativity and Quantum Cosmology 2018-05-30 v3 Cosmology and Nongalactic Astrophysics High Energy Physics - Theory

Abstract

Recently, the idea of taking ensemble average over gravity models has been introduced. Based on this idea, we study the ensemble average over (effectively) all the gravity models (constructed from Ricci scalar) dubbing the name \"uber-gravity which is a {\it{fixed point}} in the model space. The \"uber-gravity has interesting universal properties, independent from the choice of basis: i)i) it mimics Einstein-Hilbert gravity for high-curvature regime, ii)ii) it predicts stronger gravitational force for an intermediate-curvature regime, iii)iii) surprisingly, for low-curvature regime, i.e. R<R0R<R_0 where RR is Ricci scalar and R0R_0 is a given scale, the Lagrangian vanishes automatically and iiii)iiii) there is a sharp transition between low- and intermediate-curvature regimes at R=R0R=R_0. We show that the \"uber-gravity response is robust to all values of vacuum energy, ρvac\rho_{vac} when there is no other matter. So as a toy model, \"uber-gravity, gives a way to think about the hierarchy problems e.g. the cosmological constant problem. Due to the transition at R=R0R=R_0 there is a chance for \"uber-gravity to bypass Weinberg's no-go theorem. The cosmology of this model is also promising because of its non-trivial predictions for small curvature scales in comparison to Λ\LambdaCDM model.

Keywords

Cite

@article{arxiv.1703.02052,
  title  = {\"Uber-Gravity and the Cosmological Constant Problem},
  author = {Nima Khosravi},
  journal= {arXiv preprint arXiv:1703.02052},
  year   = {2018}
}

Comments

7 pages, 7 figures, match with accepted version, a comment on Weinberg's no-go theorem has been added

R2 v1 2026-06-22T18:37:34.007Z