Raychaudhuri equation in the Finsler–Randers space-time and generalized scalar-tensor theories

Stavrinos, P. C.; Alexiou, Maria

doi:10.1142/s0219887818500391

Cited by 31 publications

(48 citation statements)

References 57 publications

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“…The detailed investigation of the above construction has been performed in [54], where a metrical d-connection has been introduced and its curvature and torsion tensor coefficients have been calculated. Additionally, the Raychaudhuri equations for the model have been derived in [55].…”

Section: A the Modelmentioning

confidence: 99%

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Bounce Cosmology in Generalized Modified Gravities

et al. 2019

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We investigate the bounce realization in the framework of generalized modified gravities arising from Finsler and Finsler-like geometries. In particular, the richer intrinsic geometrical structure is reflected in the appearance of extra degrees of freedom in the Friedmann equations that can drive the bounce. We examine various Finsler and Finsler-like constructions. In the cases of general very special relativity as well as of Finsler-like gravity on the tangent bundle we show that a bounce cannot be easily obtained. However, in the Finsler-Randers space the induced scalar anisotropy can fulfill the bounce conditions and bouncing solutions are easily obtained. Finally, for the general class of theories that include a nonlinear connection a new scalar field is induced, leading to a scalar-tensor structure that can easily drive a bounce. These features reveal the capabilities of Finsler and Finsler-like geometries. 95.36.+x, 04.50.Kd

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Section: A the Modelmentioning

confidence: 99%

“…Hence, it can give us the form of anisotropy as a hypothetical field, the anisotropion, which produces this deviation from isotropy. This appears in the Friedmann equations and Lorentz violations [50][51][52][53], and thus the anisotropy arises as a property of Finslerian spacetime [50,51,54,55].…”

Section: Introductionmentioning

confidence: 99%

Bounce Cosmology in Generalized Modified Gravities

et al. 2019

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“…In the framework of Finslerian extensions, Raychaudhuri equations and energy conditions have been studied in [13,[52][53][54]. Raychaudhuri equation was developed on the tangent bundle of a spacetime and has been derived for a timelike congruence in [13].…”

Section: B Raychaudhuri Equation Of the Modelmentioning

confidence: 99%

Weak field equations and generalized FRW cosmology on the tangent Lorentz bundle

Triantafyllopoulos

Stavrinos

2018

Class. Quantum Grav.

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We study field equations for a weak anisotropic model on the tangent Lorentz bundle TM of a spacetime manifold. A geometrical extension of General Relativity (GR) is considered by introducing the concept of local anisotropy, i.e. a direct dependence of geometrical quantities on observer 4−velocity. In this approach, we consider a metric on TM as the sum of an h-Riemannian metric structure and a weak anisotropic perturbation, field equations with extra terms are obtained for this model. As well, extended Raychaudhuri equations are studied in the framework of Finsler-like extensions. Canonical momentum and mass-shell equation are also generalized in relation to their GR counterparts. Quantization of the mass-shell equation leads to a generalization of the Klein-Gordon equation and dispersion relation for a scalar field. In this model the accelerated expansion of the universe can be attributed to the geometry itself. A cosmological bounce is modeled with the introduction of an anisotropic scalar field. Also, the electromagnetic field equations are directly incorporated in this framework.

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“…If one applies the above into a cosmological framework he obtains Finsler and Finsler-like cosmologies. The basic feature of these is the appearance of extra terms in the Friedmann equations due to the intrinsic geometrical spacetime anisotropy of Finsler and Finsler-like geometries [19][20][21][22][36][37][38] (note that the term "spacetime anisotropy" in this framework is related to the Lorentz violation features of the geometry and should not be con-fused with the spatial anisotropy that can exist in Riemannian geometry too, e.g. in Bianchi cases).…”

Section: Introductionmentioning

confidence: 99%

“…Hence, one can result with an effective scalar-tensor theory arising from a Lorentz fiber bundle. The research of the Finslerian scalar-tensor theory of gravitation started in [36,37] and later in [38], giving an extension of Riemannian ansatz of the scalar-tensor theory of gravitation.…”

Section: Introductionmentioning

confidence: 99%

Cosmology of Lorentz fiber-bundle induced scalar-tensor theories

Ikeda¹,

Saridakis

Stavrinos

et al. 2019

Phys. Rev. D

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We investigate the cosmological applications of scalar-tensor theories that arise effectively from the Lorentz fiber bundle of a Finsler-like geometry. We first show that the involved nonlinear connection induces a new scalar degree of freedom and eventually a scalar-tensor theory. Using both a holonomic and a non-holonomic basis, we show the appearance of an effective dark energy sector, which additionally acquires an explicit interaction with the matter sector, arising purely from the internal structure of the theory. Applying the theory at late times we find that we can obtain the thermal history of the universe, namely the sequence of matter and radiation epochs, and moreover the effective dark-energy equation-of-state parameter can be quintessence-like, phantom-like, or experience the phantom-divide crossing during cosmological evolution. Furthermore, applying the scenario at early times we see that one can acquire an exponential de Sitter solution, as well as obtain an inflationary realization with the desired scale-factor evolution. These features arise purely from the intrinsic geometrical structure of Finsler-like geometry, and reveal the capabilities of the construction.PACS numbers: 95.36.+x, 04.50.Kd

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Raychaudhuri equation in the Finsler–Randers space-time and generalized scalar-tensor theories

Cited by 31 publications

References 57 publications

Bounce Cosmology in Generalized Modified Gravities

Bounce Cosmology in Generalized Modified Gravities

Weak field equations and generalized FRW cosmology on the tangent Lorentz bundle

Cosmology of Lorentz fiber-bundle induced scalar-tensor theories

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