arXiv subjects

G. S. Silva

Publications and source records attributed to G. S. Silva.

3 recordsLinked to original sources

arXiv2026

Cosmic structure formation in massive conformal gravity

We study the evolution of cosmological density perturbations in massive conformal gravity (MCG). We show that conformal fermionic matter alone does not generate growing density perturbations in the subhorizon regime. By introducing a conformally coupled scalar field, however, an effective cold dark matter component emerges at the effective level. The resulting coupled perturbation equations admit growing solutions with a stronger effective gravitational interaction, allowing cosmic structure formation in MCG and potentially favoring earlier structure formation at high redshifts.

gr-qc↗

arXiv2018

Unconventional minimal subtraction and Callan-Symanzik methods for Lorentz-violating scalar field theories at all loop orders

We present an explicit analytical computation of the quantum corrections, at next-to-leading order, to the critical exponents. We employ for that the Unconventional minimal subtraction, recently proposed, and the Callan-Symanzik methods to probe the universality hypothesis by comparing the outcomes for the critical exponents evaluated in both methods and the ones calculated previously in massless theories renormalized at different renormalization schemes. Furthermore, the consistency of the former method is investigated for the first time in literature, to our knowledge. At the end, we compute the critical exponents at any loop level by an induction process and furnish the physical interpretation of the results.

hep-th↗

arXiv1994

Geometrical Constraints on the Cosmological Constant

The cosmological constant problem is examined under the assumption that the extrinsic curvature of the space-time contributes to the vacuum. A compensation mechanism based on a variable cosmological term is proposed. Under a suitable hypothesis on the behavior of the extrinsic curvature, we find that an initially large $Λ(t)$ rolls down rapidly to zero during the early stages of the universe. Using perturbation analysis, it is shown that such vacuum behaves essentially as a spin-2 field which is independent of the metric.

gr-qc↗