299 citations · 845 across the 25 of their papers we have counts for
23 papers · 1 filter
Slowly rotating charged BTZ black hole solutions in Palatini Chern-Simons gravity
Flavio Bombacigno, Gonzalo J. Olmo, Emanuele Orazi +1
We consider a metric-affine formulation of Chern-Simons modified gravity in 2 + 1 dimensions. The theory is built requiring projective invariance, and the structure of the equation…
Dynamical system analysis of the cosmological phases in Palatini -essence gravity
Fabio Moretti, Flavio Bombacigno
We formulate a generalized -essence model in the presence of a Palatini gravitational sector. In the corresponding biscalar-tensor theory, we discuss the distin…
Gravitational waves in Palatini gravity for a non-minimal geometry-matter coupling
Flavio Bombacigno, Fabio Moretti, Gonzalo J. Olmo
We discuss the propagation of gravitational waves over a non-Riemannian spacetime, when a non-minimal coupling between the geometry and matter is considered in the form of contract…
Echoes from bounded universes
Renan B. Magalhães, Andreu Masó-Ferrando, Flavio Bombacigno +2
We construct a general class of modified Ellis wormholes, where one asymptotic Minkowski region is replaced by a bounded 2-sphere core, characterized by asymptotic finite areal rad…
Metric gravity with dynamical dark energy as a scenario for the Hubble tension
Giovanni Montani, Mariaveronica De Angelis, Flavio Bombacigno +1
We introduce a theoretical framework to interpret the Hubble tension, based on the combination of a metric gravity with a dynamical dark energy contribution. The modified gr…
gravity in the Jordan Frame as a Paradigm for the Hubble Tension
Tiziano Schiavone, Giovanni Montani, Flavio Bombacigno
We analyse the gravity in the so-called Jordan frame, as implemented to the isotropic Universe dynamics. The goal of the present study is to show that, according to recent d…
Landau damping for gravitational waves in parity-violating theories
Flavio Bombacigno, Fabio Moretti, Simon Boudet +1
We discuss how tensor polarizations of gravitational waves can suffer Landau damping in the presence of velocity birefringence, when parity symmetry is explicitly broken. In partic…
Torsional birefringence in metric-affine Chern-Simons gravity: gravitational waves in late-time cosmology
S. Boudet, F. Bombacigno, F. Moretti +1
In the context of the metric-affine Chern-Simons gravity endowed with projective invariance, we derive analytical solutions for torsion and nonmetricity in the homogeneous and isot…
Quasinormal modes of Schwarzschild black holes in projective invariant Chern-Simons modified gravity
Simon Boudet, Flavio Bombacigno, Gonzalo J. Olmo +1
We generalize the Chern-Simons modified gravity to the metric-affine case and impose projective invariance by supplementing the Pontryagin density with homothetic curvature terms w…
Quasinormal modes of Schwarzschild black holes in metric affine Chern-Simons theory
Flavio Bombacigno
We reformulate the Chern-Simons modified gravity in the metric-affine formalism, by enlarging the Pontryagin density with homothetic curvature terms which restore projective invari…
The role of longitudinal polarizations in Horndeski and macroscopic gravity: Introducing gravitational plasmas
Fabio Moretti, Flavio Bombacigno, Giovanni Montani
We discuss some general and relevant features of longitudinal gravitational modes in Horndeski gravity and their interaction with matter media. Adopting a gauge-invariant formulati…
Big-Bounce in projectively invariant Nieh-Yan models: the Bianchi I case
Flavio Bombacigno, Simon Boudet, Gonzalo J. Olmo +1
We show that the Nieh-Yan topological invariant breaks projective symmetry and loses its topological character in presence of non vanishing nonmetricity. The notion of the Nieh-Yan…
Big-bounce and future time singularity resolution in Bianchi I: the projective invariant Nieh-Yan case
Flavio Bombacigno, Simon Boudet, Gonzalo J. Olmo +1
We extend the notion of the Nieh-Yan invariant to generic metric-affine geometries, where both torsion and nonmetricity are taken into account. Notably, we show that the properties…
Super-entropic black hole with Immirzi hair
Simon Boudet, Flavio Bombacigno, Giovanni Montani +1
In the context of f(R) generalizations to the Holst action, endowed with a dynamical Immirzi field, we derive an analytic solution describing asymptotically Anti-de Sitter black ho…
Gravitational Landau Damping for massive scalar modes
Fabio Moretti, Flavio Bombacigno, Giovanni Montani
We establish the possibility of Landau damping for gravitational scalar waves which propagate in a non-collisional gas of particles. In particular, under the hypothesis of homogene…
Generalized Ashtekar variables for Palatini f(R) models
Flavio Bombacigno, Simon Boudet, Giovanni Montani
We consider special classes of Palatini f(R) theories, featured by additional Loop Quantum Gravity inspired terms, with the aim of identifying a set of modified Ashtekar canonical…
Scalar modes in extended hybrid metric-Palatini gravity: weak field phenomenology
Flavio Bombacigno, Fabio Moretti, Giovanni Montani
We investigate the nature of additional scalar degrees of freedom contained in extended hybrid metric-Palatini gravity, outlining the emergence of two coupled dynamical scalar mode…
Gauge invariant formulation of gravitational waves in metric gravity
Fabio Moretti, Flavio Bombacigno, Giovanni Montani
We analyze the gravitational waves propagation in metric theories of gravity. In particular, adopting a gauge invariant formalism we clearly determine the exact propagating…
Implications of the Holst term in a theory with torsion
Flavio Bombacigno, Giovanni Montani
We analyze a modified theory of gravity in the Palatini formulation, when an Holst term endowed with a dynamical Immirzi field is included. We study the basic features of th…
Big Bounce cosmology for Palatini gravity with a Nieh-Yan term
Flavio Bombacigno, Giovanni Montani
We analyze the cosmological implementation of Palatini theories, constructed with a Nieh-Yan term and solved with respect to the torsion. We consider the relevant case of th…
Semi-classical and quantum analysis of the isotropic Universe in the polymer paradigm
Giovanni Montani, Claudia Mantero, Flavio Bombacigno +2
We analyse the semi-classical and quantum dynamics of the isotropic Universe in the framework of the Polymer Quantum mechanics, in order to implement a cut-off physics on the initi…
gravity with Torsion and the Immirzi field: signature for GW detection
Flavio Bombacigno, Giovanni Montani
We propose a Nieh-Yan extension of f (R) models in the presence of Immirzi field and the resulting theory is studied in the context of first order formalism. We claim as in our mod…
Big-Bounce cosmology in the presence of Immirzi field
Flavio Bombacigno, Francesco Cianfrani, Giovanni Montani
The Immirzi parameter is promoted to be a scalar field and the Hamiltonian analysis of the corresponding dynamical system is performed in the presence of gravity. We identified som…