Accelerating Universe with spacetime torsion but without dark matter and dark energy

It is shown that cosmological equations for homogeneous isotropic models deduced in the framework of the Poincar\'e gauge theory of gravity by certain restrictions on indefinite parameters of gravitational Lagrangian take at asymptotics the same form as cosmological equations of general relativity theory for $\Lambda CDM$-model. Terms related to dark matter and dark energy in cosmological equations of standard theory for $\Lambda CDM$-model are connected in considered theory with the change of gravitational interaction provoked by spacetime torsion.Comment: 4 page

The torsion cosmology in Kaluza-Klein theory

We have studied the torsion cosmology model in Kaluza-Klein theory. We considered two simple models in which the torsion vectors are $A_{\mu}=(\alpha,0,0,0)$ and $A_{\mu}=a(t)^2(0,\beta,\beta,\beta)$, respectively. For the first model, the accelerating expansion of the Universe can be not explained without dark energy which is similar to that in the standard cosmology. But for the second model, we find that without dark energy the effect of torsion can give rise to the accelerating expansion of the universe and the alleviation of the well-known age problem of the three old objects for appropriated value of the model parameter $\beta$. These outstanding features of the second torsion cosmology model have been supported by the Type Ia supernovae (SNIa) data.Comment: 12 pages, 2 figures. Accepted for publication in JCA

Statefinder diagnostic in a torsion cosmology

We apply the statefinder diagnostic to the torsion cosmology, in which an accounting for the accelerated universe is considered in term of a Riemann-Cartan geometry: dynamic scalar torsion. We find that there are some typical characteristic of the evolution of statefinder parameters for the torsion cosmology that can be distinguished from the other cosmological models. Furthermore, we also show that statefinder diagnostic has a direct bearing on the critical points. The statefinder diagnostic divides the torsion parameter $a_1$ into differential ranges, which is in keeping with the requirement of dynamical analysis. In addition, we fit the scalar torsion model to ESSENCE supernovae data and give the best fit values of the model parameters.Comment: 18 pages, 15 figures, accepted paper in JCA

Torsion, an alternative to dark matter?

We confront Einstein-Cartan's theory with the Hubble diagram. An affirmative answer to the question in the title is compatible with today's supernovae data.Comment: 14 pp, 3 figures. Version 2 matches the version published in Gen. Rel. Grav., references added. Version 3 corrects a factor 3 in Cartan's equations to become

On Possible Light-Torsion Mixing in Background Magnetic Field

The interaction of the light with propagating axial torsion fields in the presence of an external magnetic field has been investigated. Axial torsion fields appearing in higher derivative quantum gravity possess two states, with spin one and zero, with different masses. The torsion field with spin-0 state is a ghost that can be removed if its mass is infinite. We investigate the possibility when the light mixes with the torsion fields resulting in the effect of vacuum birefringence and dichroism. The expressions for ellipticity and the rotation of light polarization axis depending on the coupling constant and the external magnetic field have been obtained.Comment: 12 pages, title changed, shortened journal version, accepted in Eur.Phys.J.

Resolution of dark matter problem in f(T) gravity

In this paper, we attempt to resolve the dark matter problem in f(T) gravity. Specifically, from our model we successfully obtain the flat rotation curves of galaxies containing dark matter. Further, we obtain the density profile of dark matter in galaxies. Comparison of our analytical results shows that our torsion-based toy model for dark matter is in good agreement with empirical data-based models. It shows that we can address the dark matter as an effect of torsion of the space.Comment: 14 pages, 3 figure

Homogeneous anisotropic cosmological models in the minimum quadratic Poincar( Gauge theory of gravity

Consiglio Nazionale delle Ricerche (CNR). Biblioteca Centrale / CNR - Consiglio Nazionale delle RichercheSIGLEITItal