Juan Luis Pérez | Searcharxiv

arXiv2026

Hamiltonian formalism for a 5-D brane cosmolgy

In this work we explores the dynamic solutions of a brane system in a five dimensional space-time under the Hamiltonian perspective, using the De Donner Weyl formalism. We obtain the dynamic equations for the scale factors, and obtain the Friedmann-like equations in general way. We present the solutions of the scale factors as a function of the extra coordinate, $y$, we show that the geometry is related to the matter-energy component in the brane. Finally, we develop the ADM formalism in the brane point of view with the foliation of the 3-dimensional space which is embedded in a 5-dimensional manifold.

hep-th↗

arXiv2026

Power law scalar potential in the Saez-Ballester like theory: Exact solutions in the Bianchi type I case

We investigate exact anisotropic Bianchi type I cosmological solutions in a generalized S'aez--Ballester--K-essence-like theory containing two interacting scalar fields with quintessence, phantom, and mixed (quintom) kinetic sectors. The scalar-field self-interaction is described by inverse power-law potentials, which admit analytical solutions after an appropriate transformation of the field equations. The mixed kinetic interaction imposes nontrivial constraints on the model parameters, leading to six exact cosmological branches associated with the quintessence, phantom, and quintom scenarios. The exact solutions provide explicit expressions for the effective volume and scalar fields, allowing the reconstruction of the Hubble parameter, the deceleration parameter, and the effective equation-of-state parameter. Although the six branches exhibit distinct transient behaviors, all physically admissible solutions evolve toward the same asymptotic de Sitter attractor characterized by accelerated expansion. The analytical solutions reveal how the different kinetic sectors control the cosmological evolution while preserving a common late-time behavior. These results provide a unified analytical description of anisotropic cosmological dynamics in generalized scalar-field theories and may serve as a useful framework for investigating the role of interacting scalar fields in the early and late evolution of the Universe.

gr-qc↗

arXiv2026

F(R,..) theories from the point of view of the Hamiltonian approach: non-vacuum Anisotropic Bianchi type I cosmological model

In this work, we will explore the effects of F(R) theories in the classical scheme using the anisotropic Bianchi Type I cosmological model with standard matter employing a barotropic fluid with equation of state $P=γρ$. In this work we present the classical solutions in two gauge, N=1 and $N=6ABCD=6η^3D$ obtaining some results that are usually used as ansatz to solve the Einstein field equation. For completeness, we present the solutions in vacuum as well.

gr-qc↗