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Mariano Anabitarte

Publications and source records attributed to Mariano Anabitarte.

At least 19 recordsLinked to original sources
arXiv2019

Quantum thermodynamics in the interior of a Schwarzschild B-H

We study the interior of a Schwarzschild Black-Hole (B-H) using Relativistic Quantum Geometry described in \cite{rb} and \cite{rb1}. We found discrete energy levels for a scalar field from a polynomial condition for Heun Confluent functions expanded around the Schwarzschild radius. From the solutions it is obtained that the uncertainty principle is valid for each energy level of space-time, in the form: $E_n\, r_{sh,n}=\hbar/2$. Temperature, entropy and the B-H mass are dependent on the number of states in the B-H, such that the Bekenstein-Hawking (BH) results are obtained in a limit case.

gr-qc↗
arXiv2019

Dark energy and large-scales solitonic back-reaction behavior in power-law inflation

We study the behavior of large-scale (cosmological) modes of back-reaction effects during inflation. We find that the group of modes which describes the very large-scale fluctuations of energy density during inflation due to back-reaction effects evolve in phase between them, but there is a tear of these modes with respect to the other modes that describe astrophysical scales. This effect could be the origin for the large-scale homogeneity and isotropy of the universe and could be a manifestation of the existence of dark energy, which is responsible for the accelerated expansion of the universe.

gr-qc↗
arXiv2018

Inflationary expansion of the universe with variable timescale

We explore a cosmological model in which the time scale is variable with the expansion of the universe and the effective spacetime is driven by the inflaton field. An example is considered and their predictions are contrasted between Planck 2018 data. We calculate the spectrum indices and the slow-rolling parameters of the effective potential. The results are in very good agreement with observations.

gr-qc↗
arXiv2017

Large scale solitonic back-reaction effects in pre-inflation

Using Relativistic Quantum Geometry (RQG), we study the emergence of back-reaction modes with solitonic properties, on astrophysical and cosmological scales, in a model of pre-inflation where the universe emerge from a topological phase transition. We found that, modes of the geometrical field that describes back-reaction effects related to larger scales (cosmological scales), are more coherent than those related to astrophysical scales, so that they can be considered a coarse-grained soliton.

gr-qc↗
arXiv2014

Inflation as a White Hole explosion from a 5D vacuum

Using a new kind of 5D Ricci-flat canonical metric, we obtain by a static foliation an effective 4D Schwarzschild-de Sitter hypersurface. We examine some particular initial conditions which could be responsible for the inflationary expansion of the early universe, which could be driven by the explosion of a White Hole (WH). The zeroth order spectrum outside the WH describes quantum fluctuations, which for a scale invariant power spectrum, can be expressed in terms of the cosmological constant, or the square mass of the WH.

gr-qc↗
arXiv2012

Dirac equation in a de Sitter expansion for massive neutrinos from modern Kaluza-Klein theory

Using the modern Kaluza-Klein theory of gravity (or the Induced Matter theory), we study the Dirac equation for massive neutrinos on a de Sitter background metric from a 5D Riemann-flat (and hence Ricci-flat) extended de Sitter metric, on which is defined the vacuum for test massless 1/2-neutral fields minimally coupled to gravity and free of any other interactions. We obtain that the effective 4D masses of the neutrinos can only take three possible values, which are related to the (static) foliation of the fifth and noncompact extra dimension.

hep-th↗
arXiv2011

Dirac equation for massive neutrinos in a Schwarzschild-de Sitter spacetime from a 5D vacuum

Starting from a Dirac equation for massless neutrino in a 5D Ricci-flat background metric, we obtain the effective 4D equation for massive neutrino in a Schwarzschild-de Sitter (SdS) background metric from an extended SdS 5D Ricci-flat metric. We use the fact that the spin connection is defined to an accuracy of a vector, so that the covariant derivative of the spinor field is strongly dependent of the background geometry. We show that the mass of the neutrino can be induced from the extra space-like dimension.

hep-th↗
arXiv2011

Particles and gravitons creation after inflation from a 5D vacuum

We use the Bogoliubov formalism to study both, particles and gravitons creation at the reheating epoch, after a phase transition from inflation to a radiation dominated universe. The modes of the inflaton field fluctuations and the scalar fluctuations of the metric at the end of inflation are obtained by using a recently introduced formalism related to the Induced Matter theory of gravity. The interesting result is that the number of created particles is bigger than $10^{90}$ on cosmological scales. Furthermore, the number of gravitons are nearly $10^{-17}$ times smaller than the number of created particles. In both cases, these numbers rapidly increases on cosmological scales.

gr-qc↗
arXiv2009

A confirmation of agreement of different approaches for scalar gauge-invariant metric perturbations during inflation

We revisit an extension of the well-known formalism for gauge-invariant scalar metric fluctuations, to study the spectrums for both, the inflaton and gauge invariant (scalar) metric fluctuations in the framework of a single field inflationary model where the quasi-exponential expansion is driven by an inflation which is minimally coupled to gravity. The proposal here examined is valid also for fluctuations with large amplitude, but for cosmological scales, where vector and tensor perturbations can be neglected and the fluid is irrotacional.

gr-qc↗
arXiv2006

Scalar Metric fluctuations in space time matter inflation

Using the Ponce de Leon background metric, which describes a 5D universe in an apparent vacuum: $\bar{G}_{AB}=0$, we study the effective 4D evolution of both, the inflaton and gauge-invariant scalar metric fluctuations, in the recently introduced model of space time matter inflation.

gr-qc↗
arXiv2006

Space Time Matter inflation

We study a model of power-law inflationary inflation using the Space-Time-Matter (STM) theory of gravity for a five dimensional (5D) canonical metric that describes an apparent vacuum. In this approach the expansion is governed by a single scalar (neutral) quantum field. In particular, we study the case where the power of expansion of the universe is $p \gg 1$. This kind of model is more successful than others in accounting for galaxy formation.

gr-qc↗
arXiv2005

Gauge-invariant metric fluctuations from NKK theory of gravity: de Sitter expansion

In this paper we study gauge-invariant metric fluctuations from a Noncompact Kaluza-Klein (NKK) theory of gravity in a de Sitter expansion. We recover the well known result $δρ/ρ\simeq 2Φ$, obtained from the standard 4D semiclassical approach to inflation. The spectrum for these fluctuations should be dependent of the fifth (spatial-like) coordinate.

gr-qc↗
arXiv2005

Inflaton field governed universe from NKK theory of gravity: stochastic approach

We study a nonperturbative single field (inflaton) governed cosmological model from a 5D Noncompact Kaluza-Klein (NKK) theory of gravity. The inflaton field fluctuations are estimated for different epochs of the evolution of the universe. We conclude that the inflaton field has been sliding down its (quadratic) potential hill along all the evolution of the universe and a mass of the order of the Hubble parameter. In the model here developed the only free parameter is the Hubble parameter, which could be reconstructed in future from Super Nova Acceleration Probe (SNAP) data.

gr-qc↗