Sunday, May 19, 2013

1305.3756 (Salvatore Capozziello et al.)

Hybrid modified gravity unifying local tests, galactic dynamics and
late-time cosmic acceleration
   [PDF]

Salvatore Capozziello, Tiberiu Harko, Francisco S. N. Lobo, Gonzalo J. Olmo
The non-equivalence between the metric and Palatini formalisms of $f(R)$ gravity is an intriguing feature of these theories. However, in the recently proposed hybrid metric-Palatini gravity, consisting of the superposition of the metric Einstein-Hilbert Lagrangian with an $f(\cal R)$ term constructed \`{a} la Palatini, the "true" gravitational field is described by the interpolation of these two non-equivalent approaches. The theory predicts the existence of a light long-range scalar field, which passes the local constraints and affects the galactic and cosmological dynamics. Thus, the theory opens new possibilities for a unified approach, in the same theoretical framework, to the problems of dark energy and dark matter, without distinguishing a priori matter and geometric sources, but taking their dynamics into account under the same standard.
View original: http://arxiv.org/abs/1305.3756

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