Salvatore Capozziello

TL;DR: In this paper, it was shown that Anti-de Sitter invariant Chern-Simons gravity can be framed within Lovelock-Zumino gravity in 5 dimensions, for particular choices of Lovellock parameters.

TL;DR: In this paper, the authors consider filamentary and planar large scale structures as possible refraction channels for electromagnetic radiation coming from cosmological structures and explain the quasar luminosity distribution and, in particular, the presence of twin and sister objects.

TL;DR: In this article, the MOND acceleration parameter a0 could be a fundamental quantity ruling the self-gravitating structures, ranging from globular clusters up to clusters of galaxies and the whole observed universe.

Abstract: The Newtonian limit of fourth-order gravity is worked out discussing its viability with respect to the standard results of General Relativity. We investigate the limit in the metric approach which, with respect to the Palatini formulation, has been much less studied in the recent literature, due to the higher-order of the field equations. In addition, we refrain from exploiting the formal equivalence of higher-order theories considering the analogy with specific scalar-tensor theories, i.e. we work in the so-called Jordan frame in order to avoid possible misleading interpretations of the results. Explicit solutions are provided for several different types of Lagrangians containing powers of the Ricci scalar as well as combinations of the other curvature invariants. In particular, we develop the Green function method for fourth-order theories in order to find out solutions. Finally, the consistency of the results with respect to General Relativity is discussed.

TL;DR: In this paper, an extension of general relativity in which an $f(R)$ term \`{a} la Palatini is added to the usual metric Einstein-Hilbert Lagrangian is presented.