Results 11 to 20 of about 1,701 (40)

Periodic Cosmological Evolutions of Equation of State for Dark Energy

, 2012
We demonstrate two periodic or quasi-periodic generalizations of the Chaplygin gas (CG) type models to explain the origins of dark energy as well as dark matter by using the Weierstrass $\wp(t)$, $\sigma(t)$ and $\zeta(t)$ functions with two periods ...
Amendola, Cai, Capozziello, Csaki, Durrer, Gulgasyl Nugmanova, Kazuharu Bamba, Kuralay Yesmakhanova, Lu, Nojiri, Petr Tsyba, Ratbay Myrzakulov, Ujjal Debnath   +12 more
core   +3 more sources

Reconstruction of the equation of state for the cyclic universes in homogeneous and isotropic cosmology

, 2013
We study the cosmological evolutions of the equation of state (EoS) for the universe in the homogeneous and isotropic Friedmann-Lema\^{i}tre-Robertson-Walker (FLRW) space-time.
A A Starobinsky, A A Starobinsky, A A Starobinsky, A Balcerzak, A Felice De, A G Riess, A J Lopez-Revelles, A V Yurov, A Y Kamenshchik, B Feng, B Feng, B G Dimitrov, B Guberina, B Jain, B McInnes, C Armendariz-Picon, C Armendariz-Picon, C Armendariz-Picon, C Cattoen, C Corda, C Corda, C Csaki, D Huterer, D J Eisenstein, D N Page, D N Spergel, D N Spergel, E Elizalde, E Elizalde, E Elizalde, E J Copeland, E Komatsu, E Komatsu, F S N Lobo, G B Zhao, G W Gibbons, H Itoyama, H K Jassal, H Stefancic, H Stefancic, H Stefancic, I Bochicchio, I Y Aref’eva, J D Barrow, J D Barrow, J D Barrow, J G Hao, J Garriga, J Khoury, J Khoury, J Khoury, J Khoury, J Sola, J Zhang, K Bamba, K Bamba, K Bamba, K Bamba, K Saaidi, L Amendola, L Fernandez-Jambrina, L Fernandez-Jambrina, L P Chimento, M Bouhmadi-Lopez, M Bouhmadi-Lopez, M C Bento, M Li, M Novello, M P Dabrowski, M P Dabrowski, M Sami, M Sami, M Tegmark, M z Li, P Creminelli, P F Gonzalez-Diaz, P J Steinhardt, P J Steinhardt, P J Steinhardt, P J Steinhardt, P P Avelino, P Peter, P Peter, P Singh, P Tretyakov, P U Wu, P X Wu, R Durrer, R G Cai, R Myrzakulov, R Myrzakulov, R Putter de, R R Caldwell, R Teh, R Y Donagi, S Capozziello, S Capozziello, S Cotsakis, S Nesseris, S Nesseris, S Nojiri, S Nojiri, S Nojiri, S Nojiri, S Nojiri, S Nojiri, S Nojiri, S Nojiri, S Nojiri, S Nojiri, S Nojiri, S Perlmutter, T Biswas, T Biswas, T Biswas, T Biswas, T Chiba, T Clifton, T Damour, T Damour, T Koivisto, T Nakamura, T P Sotiriou, U Alam, U Alam, U Alam, U Seljak, V Faraoni, V P Spiridonov, V Sahni, V Sahni, W Godlowski, X F Zhang, Y F Cai, Y F Cai, Y F Cai, Y S Piao, Y S Piao, Y Shtanov, Y Shtanov, Z -G Liu   +140 more
core   +1 more source

Lagrangian formulation for Mathisson-Papapetrou-Tulczyjew-Dixon (MPTD) equations

, 2015
We obtain Mathisson-Papapetrou-Tulczyjew-Dixon equations of a rotating body with given values of spin and momentum starting from Lagrangian action without auxiliary variables. MPTD-equations correspond to minimal interaction of our spinning particle with
Deriglazov, Alexei A., Ramírez, Walberto Guzmán   +1 more
core   +1 more source

Dark Energy in F(R,T) Gravity

, 2020
Since the discovery of cosmic acceleration, modified gravity theories play an important role in the modern cosmology. In particular, the well-known F(R)-theories reached great popularity motivated by the easier formalism and by the prospect to find a ...
Myrzakulov, Ratbay
core  

Influence of $f(R)$ Models on the Existence of Anisotropic Self-Gravitating Systems

, 2017
This paper aims to explore some realistic configurations of anisotropic spherical structures in the background of metric $f(R)$ gravity, where $R$ is the Ricci scalar. The solutions obtained by Krori and Barua are used to examine the nature of particular
Bhatti, M. Z., Ilyas, M., Sharif, M., Yousaf, Z.   +3 more
core   +1 more source

Anisotropic fluid for a set of non-diagonal tetrads in f(T) gravity

, 2012
We consider $f(T)$ gravity for a Weitzenbock spherically symmetric and static spacetime, where the metric is projected in the tangent space to the manifold for a set of non-diagonal tetrads.
Daouda, M. Hamani, Houndjo, M. J. S., Rodrigues, Manuel E.   +2 more
core   +1 more source

The non-Abelian Weyl-Yang-Kaluza-Klein gravity model

, 2013
The Weyl-Yang gravitation gauge theory is investigated in the framework of a pure higher-dimensional non-Abelian Kaluza-Klein background. We construct the dimensionally reduced field equations and energy-momentum tensors as well as the four dimensional ...
Kuyrukcu, H.
core   +1 more source

Spacetimes dressed with stealth electromagnetic fields

, 2018
Stealth field configurations by definition have a vanishing energy-momentum tensor, thus do not contribute to the gravitational field equations. While only trivial fields can be stealth in Maxwell's electrodynamics, nontrivial stealth fields appear in ...
Smolić, Ivica
core   +1 more source

Another possible interplay between gravitation and cosmology [PDF]

, 2010
I describe here some features of a non-geometrical approach to quantum gravity which leads to another picture of ties of gravitation and cosmology.
Ivanov, Michael A.
core   +1 more source

A non-geometrical approach to quantum gravity [PDF]

, 2009
Some results of author's work in a non-geometrical approach to quantum gravity are reviewed here, among them: a quantum mechanism of classical gravity giving a possibility to compute the Newton constant; asymptotic freedom at short distances; interaction
Ivanov, Michael A.
core   +1 more source