A Modified Gravitational Theory of the Matter Sector of the Type $ϕ(R,T)\mathcal{L}_{m}$

Fuente: arXiv
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Autori principali: Teruel, Gines R. Pérez, Peña, Antonio Peña
Natura: Preprint
Pubblicazione: 2025
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author Teruel, Gines R. Pérez
Peña, Antonio Peña
author_facet Teruel, Gines R. Pérez
Peña, Antonio Peña
contents We investigate a modified gravity framework where the geometric Einstein--Hilbert sector remains untouched while the matter Lagrangian is weighted by a nontrivial function $ϕ(T)$ of the energy--momentum trace. Unlike $f(R,T)$ or $f(R,\mathcal L_m)$ theories, this construction alters how matter curves spacetime without introducing extra geometric degrees of freedom, thereby remaining consistent with local tests of gravity. Physically, the factor $ϕ(T)\mathcal L_m$ can be interpreted as an effective renormalization of the matter sector, relevant at high densities and smoothly reducing to GR at low densities. Within this setup we identify a robust window in parameter space leading to a smooth and nonsingular cosmological bounce, with bounded density, finite $\dot H>0$ at the bounce, and preservation of the infrared limit where $Λ$CDM is recovered. This mechanism provides a natural route to singularity resolution while retaining the empirical successes of standard cosmology.
format Preprint
id arxiv_https___arxiv_org_abs_2511_06811
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Modified Gravitational Theory of the Matter Sector of the Type $ϕ(R,T)\mathcal{L}_{m}$
Teruel, Gines R. Pérez
Peña, Antonio Peña
General Relativity and Quantum Cosmology
We investigate a modified gravity framework where the geometric Einstein--Hilbert sector remains untouched while the matter Lagrangian is weighted by a nontrivial function $ϕ(T)$ of the energy--momentum trace. Unlike $f(R,T)$ or $f(R,\mathcal L_m)$ theories, this construction alters how matter curves spacetime without introducing extra geometric degrees of freedom, thereby remaining consistent with local tests of gravity. Physically, the factor $ϕ(T)\mathcal L_m$ can be interpreted as an effective renormalization of the matter sector, relevant at high densities and smoothly reducing to GR at low densities. Within this setup we identify a robust window in parameter space leading to a smooth and nonsingular cosmological bounce, with bounded density, finite $\dot H>0$ at the bounce, and preservation of the infrared limit where $Λ$CDM is recovered. This mechanism provides a natural route to singularity resolution while retaining the empirical successes of standard cosmology.
title A Modified Gravitational Theory of the Matter Sector of the Type $ϕ(R,T)\mathcal{L}_{m}$
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2511.06811