arXiv subjects

Omar E. Núñez

Publications and source records attributed to Omar E. Núñez.

5 recordsLinked to original sources

arXiv2019

Classical and quantum exact solutions for the anisotropic Bianchi type I in multi-scalar field cosmology with an exponential potential driven inflation

The anisotropic Bianchi type I in multi-scalar field cosmology is studied with a particular potential of the form $\rm V= V_0 e^{-\left[λ_1 ϕ_1 + \cdots + λ_n ϕ_n \right]}\,,$ which emerges as a condition between the time derivatives of their corresponding momenta. Using the Hamiltonian formalism for the inflation epoch with a quintessence framework we find the exact solutions for the Einstein-Klein-Gordon (EKG) system with different scenarios specified by the parameter $\rm λ^2= \sum_{i=1}^n λ_i^2$. For the quantum scheme of this model, the corresponding Wheeler-DeWitt (WDW) equation is solved by applying an appropriate change of variables and suitable ansatz.

gr-qc↗

arXiv2018

Classical and quantum exact solutions for a FRW multi-scalar field cosmology with an exponential potential driven inflation

A flat Fiedmann-Robertson-Walker (FRW) multi-scalar field cosmology is studied with a particular potential of the form $ \rm V(ϕ,σ)=V_0 e^{-λ_1 ϕ-λ_2 σ}$, which emerges as a relation between the time derivatives of the scalars field momenta. Classically, by employing the Hamiltonian formalism of two scalar fields $\rm(ϕ,σ)$ with standard kinetic energy, exact solutions are found for the Einstein-Klein-Gordon (EKG) system for different scenarios specified by the parameter $\rmλ^2=λ_1^2+λ_2^2$, as well as the e-folding function $\rm N_{e}$ which is also computed. For the quantum scheme of this model, the corresponding Wheeler-DeWitt (WDW) equation is solved by applying an appropriate change of variables.

gr-qc↗

arXiv2018

Hamilton's approach in cosmological inflation with an exponential potential and its observational constraints

The Friedmann-Robertson-Walker (FRW) cosmology is analyzed with a general potential $\rm V(ϕ)$ in the scalar field inflation scenario. The Bohmian approach (a WKB-like formalism) was employed in order to constraint a generic form of potential to the most suited to drive inflation, from here a family of potentials emerges; in particular we select an exponential potential as the first non trivial case and remains the object of interest of this work. The solution to the Wheeler-DeWitt (WDW) equation is also obtained for the selected potential in this scheme. Using Hamilton's approach and equations of motion for a scalar field $\rm ϕ$ with standard kinetic energy, we find the exact solutions to the complete set of Einstein-Klein-Gordon (EKG) equations without the need of the slow-roll approximation (SR). In order to contrast this model with observational data (Planck 2018 results), the inflationary observables: the tensor-to-scalar ratio and the scalar spectral index are derived in our proper time, and then evaluated under the proper condition such as the number of e-folding corresponds exactly at 50-60 before inflation ends. The employed method exhibits a remarkable simplicity with rather interesting applications in the near future.

gr-qc↗

arXiv2017

Cosmological super inflation using Hamilton's approach

The Friedmann-Robertson-Walker (FRW) cosmology is analyzed with a particular potential $\rm V(ϕ)=V_0 e^{-\sqrt{3} ϕ}$ in the quintessence field scenario, which emerges in the supersymmetric quantum mechanics (SUSY) formalism. Using Hamilton's approach for a scalar field $ϕ$ with standard kinetic energy, and the Hamilton equations, we find exact solutions to the complete set of the Einstein-Klein-Gordon equations without the need of the slow-roll conditions in order to model the inflation phenomenon. We find that the solutions are in good agreement with the inflationary conditions such as the e-folding function ${\cal N}$ which corresponds to the $Ω$ function in the Misner parametrization for the scale factor $\rm A(t)=e^{Ω(t)}$ when evaluated in $\rm Δt$, which is the time interval for the inflation period. The acceleration of the scale factor was computed and it was found to be positive for the inflation period with a range of values for the parameters of the model. Quantum solution from the Wheeler-DeWitt equation is presented, where the wave function in relation to the evolution of the scale factor, shows that for this period of time at larger values of $\rm A$ and for any value of scalar-field $\rm φ$, the wave function is peaked.

gr-qc↗

arXiv2017

Scalar potentials with Multi-scalar fields from quantum cosmology and supersymmetric quantum mechanics

The Multi-scalar field cosmology of the anisotropic Bianchi type I model is used in order to construct a family of potentials that are the best suited to model the inflation phenomenon. We employ the quantum potential approach to quantum mechanics due to Bohm in order to solve the corresponding Wheeler-DeWitt equation; which in turn enables us to restrict sensibly the aforementioned family of potentials. Supersymmetric Quantum Mechanics (SUSYQM) is also employed in order to constrain the superpotential function, at the same time the tools from SUSY Quantum Mechanics are used to test the family of potentials in order to infer which is the most convenient for the inflation epoch. For completeness solutions to the wave function of the universe are also presented.

gr-qc↗