Strong gravity effects on R2-corrected single scalar field inflation and compatibility with the ACT data
Oikonomou V.K.
December 2025Elsevier B.V.
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
2025#871
In this work we introduce the rescaled R 2 -corrected minimally coupled scalar field theory, a theory that contains minimal quantum corrections of the single scalar field Lagrangian. We develop the theoretical framework in the Jordan frame where the baryons geodesics are free fall geodesics and we do not treat the theory as a two scalar field theory in the Einstein frame. The theoretical framework can be reduced to a single scalar field theory framework by using a perturbative expansion at the level of the field equations, making the resulting theory easy to tackle analytically. The first two quantum corrections contain two terms, a linear ∼ R and a quadratic term ∼ R 2 . The effect of the linear term alters the Einstein-Hilbert term, making the resulting theory a rescaled version of Einstein-Hilbert gravity. Due to the presence of the rescaled Einstein-Hilbert term ∼ λ R 16 π G , the gravitational constant will no longer be that of Newton’s, but a rescaled one G λ and hence gravity can be stronger primordially, or even weaker. The perspective of having stronger gravity primordially, is compatible with intuition, since one expects a stronger gravity primordially, but having a weaker gravity for some reason is not prohibited theoretically. The attribute of our theoretical framework is that it allows a stronger gravity primordially, which returns to ordinary gravity as the curvature of the Universe decreases. We examine the effects of the quantum terms on several mainstream scalar field inflationary potentials, such as hybrid inflation, monomial inflation and power-law inflation, and we demonstrate that the hybrid inflation and power-law inflation, which are 3-parameter models, are compatible with the Atacama Cosmology Telescope data in the strong gravity limit, while the monomial inflation, which is a 4-parameter model, can be compatible with the Atacama Cosmology Telescope data in the weak gravity limit, however the model suffers from perturbative expansion break down during inflation.
ACT , Effective field theory , Inflation
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Department of Physics, Aristotle University of Thessaloniki, Thessaloniki, 54124, Greece
L.N. Gumilyov, Eurasian National University - Astana, 010008, Kazakhstan
Department of Physics
L.N. Gumilyov
10 лет помогаем публиковать статьи Международный издатель
Книга Публикация научной статьи Волощук 2026 Book Publication of a scientific article 2026