Dirac spinors in Bianchi-I <i>f</i>(<i>R</i>)-cosmology with torsion

Vignolo, Stefano; Fabbri, Luca; Cianci, Roberto

doi:10.1063/1.3658865

Cited by 57 publications

(65 citation statements)

References 25 publications

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“…In many recent works, it has been shown that the spinor field possesses non-diagonal components of the energy momentum tensor [7,35]. The main question arises that what is the reason for non-triviality of non-diagonal components of the energy-momentum tensor?…”

Section: The Spinor Inflationary Model Of Universe In Super String Thmentioning

confidence: 99%

Bianchi Type I Cosmology with Scalar and Spinor Tachyon

2014

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Recently, some authors propose a scenario where inflation is driven by scalar and spinor fields. In this scenario, the universe undergoes anisotropic inflationary expansion due to a preferred direction dominated by spinor. The main question arises that what is the origin of spinor inflation in 4D Universe? To answer to this question , we propose a new model in super string theory that allows to take into account the spinor string tachyon in additional to scalar one which stretch between branes and antibranes. In this model, the inflation of 4D Universe is controlled by the spinor type of tachyon and evolves from nonphantom phase to phantom one and consequently, phantom-dominated era of the universe accelerates and ends up in big-rip singularity. We test our model against WMAP and Planck data and obtain the ripping time. We find that the finite time that Big Rip singularity occurs is t = 65(Gyr). According to our calculations, N 60 case leads to n s 0.96, where N and n s are the number e-folds and the spectral index respectively. Thus our results are consistent with experimental data and thus the spinor inflationary model works.

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Section: The Spinor Inflationary Model Of Universe In Super String Thmentioning

confidence: 99%

Bianchi Type I Cosmology with Scalar and Spinor Tachyon

2014

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“…generalizing the usual relations that hold in a Zeld'ovich universe. The Jacobs parametrisation, given by the first equation in (26), still holds although with a time dependent δ = √ Ω Σ . From the definition (30), the time-dependent quasi-Kasner exponents satisfy the differential equatioṅ…”

Section: A Definition Of Quasi-kasner Exponentsmentioning

confidence: 99%

A generalized Kasner transition for bouncing Bianchi I models in modified gravity theories

Cesare

Wilson-Ewing

2019

J. Cosmol. Astropart. Phys.

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We derive transition rules for Kasner exponents in bouncing Bianchi I models with generic perfect fluid matter fields for a broad class of modified gravity theories where cosmological singularities are resolved and replaced by a non-singular bounce. This is a generalization of results obtained previously in limiting curvature mimetic gravity and loop quantum cosmology. A geometric interpretation is provided for the transition rule as a linear map in the Kasner plane. We show that the general evolution of anisotropies in a Bianchi I universe-including during the bounce phase-is equivalent to the motion of a point particle on a sphere, where the sphere is the one-point compactification of the Kasner plane. In addition, we study the evolution of anisotropies in a large family of bouncing Bianchi I space-times. We also present a novel explicit solution to the Einstein equations for a Bianchi I universe with ekpyrotic matter with a constant equation of state ω = 3. *

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“…Regarding type-6 spinors, still J = 0 and K = 0, however, the flag S is zero, terming it a dipole spinor field. Flagdipole spinor fields were shown to be a legitimate solution of the Dirac field equation in a torsional setup [6][7][8], whereas Elko and Majorana uncharged spinor fields represent type-5 spinors, although a recent example of a charged flag-pole spinor has been shown to be a solution of the Dirac equation [9]. More physical important examples on the Lounesto classification can be found in Refs.…”

Section: General Bilinear Covariants and Spinor Field Classesmentioning

confidence: 99%

Opening the Pandora’s box of quantum spinor fields

2018

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Lounesto's classification of spinors is a comprehensive and exhaustive algorithm that, based on the bilinears covariants, discloses the possibility of a large variety of spinors, comprising regular and singular spinors and their unexpected applications in physics and including the cases of Dirac, Weyl, and Majorana as very particular spinor fields. In this paper we pose the problem of an analogous classification in the framework of second quantization. We first discuss in general the nature of the problem. Then we start the analysis of two basic bilinear covariants, the scalar and pseudoscalar, in the second quantized setup, with expressions applicable to the quantum field theory extended to all types of spinors. One can see that an ampler set of possibilities opens up with respect to the classical case. A quantum reconstruction algorithm is also proposed. The Feynman propagator is extended for spinors in all classes.

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Dirac spinors in Bianchi-I f(R)-cosmology with torsion

Cited by 57 publications

References 25 publications

Bianchi Type I Cosmology with Scalar and Spinor Tachyon

Bianchi Type I Cosmology with Scalar and Spinor Tachyon

A generalized Kasner transition for bouncing Bianchi I models in modified gravity theories

Opening the Pandora’s box of quantum spinor fields

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