Confronting rainbow-deformed f(R) gravity with the ACT data

Odintsov S.D. Oikonomou V.K.
November 2025 Elsevier B.V.

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
2025 #870

In this work we examine a theoretical scenario which combines two fundamental theoretical proposals for the early Universe and a possible evolution for the early post-inflationary epoch. Specifically, we assume that the early Universe contains gravitys rainbow effects on the spacetime and the inflationary Lagrangian contains R² corrections or f(R) gravity corrections in general. In addition we assume that the era beyond the end of inflation until the reheating temperature is reached, is a kination era. Both theories, R² and gravitys rainbow emerge from a quantum context so their effects should be first checked at the theory which connects the quantum with the classical, hence inflation. Spacetime is four dimensional and the effects of the quantum theory could possibly be imprinted in the inflationary Lagrangian and of course on the spacetime itself. For the gravitys rainbow deformed Starobinsky model, both Lagrangian quantum effects and spacetime quantum effects are combined. As we show the resulting theory is compatible with the ACT data, regarding the spectral index. We also consider power-law f(R) gravity deformations and we show that in this case, the model is viable without the need of extending the slow-roll era of inflation.

04.50.Kd , 11.25.-w , 95.36.+x , 98.80.-k , 98.80.Cq , ACT , ACT cosmology , f(R) gravity , Gravitys rainbow , Starobinsky model

Text of the article Перейти на текст статьи

Institute of Space Sciences (ICE, CSIC) C. Can Magrans s/n, Barcelona, 08193, Spain
ICREA, Passeig Luis Companys, 23, Barcelona, 08010, Spain
Institut dEstudis Espacials de Catalunya (IEEC), Castelldefels, Catalonia, Barcelona, 08860, Spain
L.N. Gumilyov Eurasian National University - Astana, 010008, Kazakhstan
Department of Physics, Aristotle University of Thessaloniki, Thessaloniki, 54124, Greece

Institute of Space Sciences (ICE
ICREA
Institut dEstudis Espacials de Catalunya (IEEC)
L.N. Gumilyov Eurasian National University - Astana
Department of Physics

10 лет помогаем публиковать статьи Международный издатель

Книга Публикация научной статьи Волощук 2026 Book Publication of a scientific article 2026