The effect of spin generated torsion on the early universe's evolution

Wolf, C.

doi:10.1007/bf02148646

Cited by 15 publications

(9 citation statements)

References 25 publications

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“…'s [161,191,8] where other, similar, non-singular solutions were obtained) and may have some interest for cosmology. We notice that the second-derivative inflationary models with torsion have attracted some interest recently, in particular they were used for the analysis of the cosmic perturbations [148,81].…”

Section: An Example Of the Possible Effect Of Classical Torsionmentioning

confidence: 84%

Physical aspects of the space–time torsion

2002

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Abstract. We review many quantum aspects of torsion theory and discuss the possibility of the space-time torsion to exist and to be detected. The paper starts, in Chapter 2, with a pedagogical introduction to the classical gravity with torsion, that includes also interaction of torsion with matter fields. Special attention is paid to the conformal properties of the theory. In Chapter 3, the renormalization of quantum theory of matter fields and related topics, like renormalization group, effective potential and anomalies, are considered. Chapter 4 is devoted to the action of spinning and spinless particles in a space-time with torsion, and to the discussion of possible physical effects generated by the background torsion. In particular, we review the upper bounds for the magnitude of the background torsion which are known from the literature. In Chapter 5, the comprehensive study of the possibility of a theory for the propagating completely antisymmetric torsion field is presented. It is supposed that the propagating field should be quantized, and that its quantum effects must be described by, at least, some effective low-energy quantum field theory. We show, that the propagating torsion may be consistent with the principles of quantum theory only in the case when the torsion mass is much greater than the mass of the heaviest fermion coupled to torsion. Then, universality of the fermion-torsion interaction implies that torsion itself has a huge mass, and can not be observed in realistic experiments. Thus, the theory of quantum matter fields on the classical torsion background can be formulated in a consistent way, while the theory of dynamical torsion meets serious obstacles. In Chapter 6, we briefly discuss the string-induced torsion and the possibility to induce torsion action and torsion itself through the quantum effects of matter fields.

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Section: An Example Of the Possible Effect Of Classical Torsionmentioning

confidence: 84%

Physical aspects of the space–time torsion

2002

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“…The repulsive contributions of torsion to the energy-momentum tensor yield cosmological models which are free from singularities. [126][127][128] Topological defects originated from torsion, in a universe characterized by phase transitions, [129][130][131] are reflected today into the angular momenta of cosmic structures. Furthermore, the energymomentum contribution of torsion influences the cosmological perturbations giving rise to characteristic lengths in the spectrum.…”

Section: Gravity With Torsionmentioning

confidence: 99%

Extended gravity cosmography

Capozziello

D’Agostino

Luongo

2019

Int. J. Mod. Phys. D

369

231

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Cosmography can be considered as a sort of a model-independent approach to tackle the dark energy/modified gravity problem. In this review, the success and the shortcomings of the ΛCDM model, based on General Relativity and standard model of particles, are discussed in view of the most recent observational constraints. The motivations for considering extensions and modifications of General Relativity are taken into account, with particular attention to f (R) and f (T ) theories of gravity where dynamics is represented by curvature or torsion field respectively. The features of f (R) models are explored in metric and Palatini formalisms. We discuss the connection between f (R) gravity and scalar-tensor theories highlighting the role of conformal transformations in the Einstein and Jordan frames. Cosmological dynamics of f (R) models is investigated through the corresponding viability criteria. Afterwards, the equivalent formulation of General Relativity (Teleparallel Equivalent General Relativity) in terms of torsion and its extension to f (T ) gravity is considered. Finally, the cosmographic method is adopted to break the degeneracy among dark energy models. A novel approach, built upon rational Padé and Chebyshev polynomials, is proposed to overcome limits of standard cosmography based on Taylor expansion. The approach provides accurate model-independent approximations of the Hubble flow. Numerical analyses, based on Monte Carlo Markov Chain integration of cosmic data, are presented to bound coefficients of the cosmographic series. These techniques are thus applied to reconstruct f (R) and f (T ) functions and to frame the late-time expansion history of the universe with no a priori assumptions on April 3, 2019 0:31 WSPC/INSTRUCTION FILE Review 2 S. Capozziello, R. D'Agostino, O. Luongo its equation of state. A comparison between the ΛCDM cosmological model with f (R) and f (T ) models is reported.

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“…Besides, several people agree with the line of thinking that torsion could have played some specific role in the dynamics of the early universe and, by the way, it could have yielded macroscopically observable effects today. In fact, the presence of torsion naturally gives repulsive contributions to the energy-momentum tensor so that cosmological models become singularity-free [21][22][23][24][25][26][27][28][29][30]. This feature, essentially, depends on spin alignments of primordial particles which can be considered as the source of torsion [31].…”

Section: Contentsmentioning

confidence: 99%