Covariant Gauge Invariant Theory of Scalar Perturbations in f(R)- Gravity: A Brief Review~!2009-09-27~!2009-09-30~!2010-06-03~!

Covariant Gauge Invariant Theory of Scalar Perturbations in f(R)- Gravity: A Brief Review

I review the state of the art of the investigation on the structure formation in f(R)-gravity based on the Covariant and Gauge Invariant approach to perturbations. A critical analysis of the results, in particular the presence of characteristic signature of these models together with their meaning and their implication, is given.

A Covariant and Gauge-invariant Analysis of Cmb Anisotropies from Scalar Perturbations

We present a new, fully covariant and manifestly gauge-invariant expression for the temperature anisotropy in the cosmic microwave background radiation resulting from scalar perturbations. We pay particular attention to gauge issues such as the definition of the temperature perturbation and the placing of the last scattering surface. In the instantaneous recombination approximation, the express...

cosmological density fluctuations and gravity waves: a covariant approach to gauge-invariant non-linear perturbation theory

We present a new approach to gauge-invariant cosmological perturbations at second order, which is also covariant. We examine two cases in particular for a dust Friedman-Lemâıtre-RobertsonWalker model of any curvature: we investigate gravity waves generated from clustering matter, that is, induced tensor modes from scalar modes; and we discuss the generation of density fluctuations induced by gr...

Metrafenone 11/03/09

Memo CS – 03 – 09

This paper concerns infrastructural work in the fields of Language Engineering, Natural Language Processing and Computational Linguistics. We begin by defining the area of software support for research and development of components in these areas as Software Architecture for Language Engineering (SALE). The rest of the paper reviews contributions to this field, covering a wide range of work ove...