Generalized tachyonic teleparallel cosmology

Bahamonde, Sebastián; Marciu, Mihai; Said, Jackson Levi

doi:10.1140/epjc/s10052-019-6833-1

Cited by 24 publications

(21 citation statements)

References 85 publications

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“…( 14) can be regarded as a "good vielbein". Similarly, in the FRW cosmological models the f (T, B) gravitational dynamics preserves the form of the usual Friedmann equations (two equations) [37][38][39][40][41][42]. The choice of vielbein is a rather important issue, as it fixes the number of degrees of freedom of the theory, as seen particularly in a gravitational wave analysis of f (T, B) gravity [50].…”

Section: Metric Equationsmentioning

confidence: 99%

“…A new teleparallel gravity model is the f (T, B) gravity, where B is the boundary term [34][35][36], that has attracted a lot of attention due this model features have, as well as good agreement with observational data to describe the accelerated expansion of the universe [37,38], and their significant results in cosmological perturbations and thermodynamics, and dark energy, and gravitational waves [39][40][41][42][43][44][45]. Furthermore, the gravity f (T, B) was studied in a brane scenario, where it was possible to observe that the additional term B induces changes on the energy density causing a split in the brane, also changing the gravitational perturbations [46].…”

Section: Introductionmentioning

confidence: 99%

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Fermion localization in braneworld teleparallel f(T, B) gravity

2021

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We study a spin 1/2 fermion in a thick braneworld in the context of teleparallel f(T, B) gravity. Here, f(T, B) is such that $$f_1(T,B)=T+k_1B^{n_1}$$ f 1 ( T , B ) = T + k 1 B n 1 and $$f_2(T,B)=B+k_2T^{n_2}$$ f 2 ( T , B ) = B + k 2 T n 2 , where $$n_{1,2}$$ n 1 , 2 and $$k_{1,2}$$ k 1 , 2 are parameters that control the influence of torsion and the boundary term. We assume Yukawa coupling, where one scalar field is coupled to a Dirac spinor field. We show how the $$n_{1,2}$$ n 1 , 2 and $$k_{1,2}$$ k 1 , 2 parameters control the width of the massless Kaluza–Klein mode, the breadth of non-normalized massive fermionic modes and the properties of the analogue quantum-potential near the origin.

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Section: Metric Equationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fermion localization in braneworld teleparallel f(T, B) gravity

2021

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“…However, when in analogy to the curvature based f (R) and scalar-tensor gravity, one extends the teleparallel theory by e.g. introducing an arbitrary function arXiv:1905.03305v2 [gr-qc] 29 Jul 2019 of the torsion scalar, f (T) [21,22], or nonminimally coupled scalar field in the action [23,24], or generalizes the theory further [25][26][27][28][29][30][31], then the field equations start to differ from their curvature based counterparts, and consequently can offer new or modified solutions.…”

Section: Introductionmentioning

confidence: 99%

Flat Connection for Rotating Vacuum Spacetimes in Extended Teleparallel Gravity Theories

et al. 2019

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Teleparallel geometry utilizes Weitzenböck connection which has nontrivial torsion but no curvature and does not directly follow from the metric like Levi-Civita connection. In extended teleparallel theories, for instance in f (T) or scalar-torsion gravity, the connection must obey its antisymmetric field equations. So far only a few analytic solutions were known. In this note we solve the f (T, φ) gravity antisymmetric vacuum field equations for a generic rotating tetrad ansatz in Weyl canonical coordinates, and find the corresponding spin connection coefficients. By a coordinate transformation we present the solution also in Boyer-Lindquist coordinates, often used to study rotating solutions in general relativity. The result hints for the existence of another branch of rotating solutions besides the Kerr family in extended teleparallel gravities.

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“…For example, in [45,46], the authors found a Teleparallel theory containing non-minimally couplings between a scalar field and both the scalar torsion T and the boundary term B, finding that this theory contains the standard non-minimally coupled theories based on the curvature [47,48]. This was further generalised to quintom models [49], non-local models [50,51] and specific scalar tensor scenarios [52][53][54], finding again that Teleparallel theories are broader than standard modified theories. Recently, a Teleparallel Horndeski theory was derived which can be written as standard Horndeski plus a correction depending on torsion [55].…”

Section: Introductionmentioning

confidence: 92%

String-inspired Teleparallel Cosmology

Bahamonde,

Marciu,

Odintsov

et al. 2020

Preprint

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The present paper represents an attempt for a very generic string inspired theory of gravitation, based on a stringy action in the teleparallel gravity which includes a specific functional which depends on the scalar field and its kinetic energy, as well as the torsion and boundary terms, embedding also possible effects from the teleparallel Gauss-Bonnet invariants. After we deduce the field equations for the associated generic theory of gravitation, we focus on string inspired couplings which are studied by considering different analytical techniques. The first analytical technique is based on the linear stability theory, by introducing proper dimensionless variables which enables us to study the structure of the phase space and the associated physical effects. In this case we have obtained different cosmological solutions which corresponds to matter and dark energy dominated solutions, achieving a possible transition between matter and dark energy dominated epochs. For each type of cosmological solutions we have discussed the corresponding physical features, attaining viable constraints for the coupling constants due to dynamical effects. The dynamical study of the physical features included also a numerical analysis by fine-tuning the initial conditions deep into the matter era, obtaining possible trajectories for the effective equation of state for specific coupling functions.

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Generalized tachyonic teleparallel cosmology

Cited by 24 publications

References 85 publications

Fermion localization in braneworld teleparallel f(T, B) gravity

Fermion localization in braneworld teleparallel f(T, B) gravity

Flat Connection for Rotating Vacuum Spacetimes in Extended Teleparallel Gravity Theories

String-inspired Teleparallel Cosmology

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