204 citations · 1.2k across the 40 of their papers we have counts for
24 papers · 1 filter
Non conservative conformal Killing gravity: coupling the dark sector with curvature and matter
Salvatore Capozziello, Carlo Alberto Mantica, Luca Guido Molinari
The so called Harada gravity with non conserved energy-momentum tensor is here taken into account. It includes Rastall gravity as a special case. The field equations are written as…
Constraints on cosmological parameters and CMB first acoustic peak in conformal Killing gravity
Salvatore Capozziello, Carlo Alberto Mantica, Luca Guido Molinari +1
In the frame of conformal Killing gravity cosmology, we performed a Bayesian analysis on two different datasets of Baryon Acoustic oscillations (DESI and SDSS DR16), two datasets o…
Note on conserved currents in static Conformal Killing Gravity
Carlo Alberto Mantica, Luca Guido Molinari
Conserved currents are discussed for static Conformal Killing Gravity, with explicit expressions in static spherical symmetry with anisotropic matter fluid or coupled to (non)linea…
Tolman-Oppenheimer-Volkoff equation and static spheres in Conformal Killing gravity
Carlo Alberto Mantica, Luca Guido Molinari
We derive the analog of the Tolman - Oppenheimer - Volkoff equation in conformal Killing gravity in a static spherically symmetric spacetime, sourced by anisotropic fluid matter. I…
Conformal Killing gravity in static spherically-symmetric spacetimes
Carlo Alberto Mantica, Luca Guido Molinari
We identify an anisotropic divergence-free conformal Killing tensor for static spherically symmetric spacetimes, and write the conformal Killing gravity equations as Einst…
Conformal Killing cosmology -- Geometry, dark sector, growth of structures, and big rip
Carlo Alberto Mantica, Luca Guido Molinari
We introduce Sinyukov-like tensors, a special kind of conformal Killing tensors. In Robertson-Walker space-times they have the perfect-fluid form and only depend on two constants a…
Second Response to the critique of "Cotton Gravity''
R. A. Sussman, C. A. Mantica, L. G. Molinari +1
Clement and Noiucer submitted a note {\tt arXiv:2401.16008 [gr-qc]} replying to our criticism {\tt arXiv:2401.10479 [gr-qc]} of their previous submission. We reply to the contents…
Friedmann equations in the Codazzi parametrization of Cotton and extended theories of gravity and the Dark Sector
Carlo Alberto Mantica, Luca Guido Molinari
The Friedmann equations of Cotton gravity provide a simple parametrization to reproduce, by tuning a single function, the Friedmann equations of several extensions of gravity, such…
Response to a critique of "Cotton Gravity"
Roberto A Sussman, Carlo Alberto Mantica, Luca Guido Molinari +1
We address in this article the criticism in a recently submitted article by Clement and Noiucer (arXiv:2312.17662 [gr-qc]) on "Cotton Gravity" (CG), a gravity theory alternative to…
A note on Harada's Conformal Killing gravity
Carlo Alberto Mantica, Luca Guido Molinari
We show that "Gravity at cosmological distances: Explaining the accelerating expansion without dark energy" recently proposed by J. Harada [6] is equivalent to the Einstein equatio…
The covariant approach to static spacetimes in Einstein and extended gravity theories
Carlo Alberto Mantica, Luca Guido Molinari
We present a covariant study of static space-times, as such and as solutions of gravity theories. By expressing the relevant tensors through the velocity and the acceleration vecto…
Codazzi tensors and their space-times, and Cotton gravity
Carlo Alberto Mantica, Luca Guido Molinari
We study the geometric properties of certain Codazzi tensors for their own sake, and for their appearance in the recent theory of Cotton gravity. We prove that a perfect-fluid tens…
Spherical doubly warped spacetimes for radiating stars and cosmology
Carlo Alberto Mantica, Luca Guido Molinari
Spherically symmetric spacetimes are ambient spaces for models of stellar collapse and inhomogeneous cosmology. We obtain results for the Weyl tensor and the covariant form of the…
Geometric Perfect Fluids from Extended Gravity
Salvatore Capozziello, Carlo Alberto Mantica, Luca Guido Molinari
A main issue in cosmology and astrophysics is whether the dark sector phenomenology originates from particle physics, then requiring the detection of new fundamental components, or…
Doubly Torqued Vectors and a classification of Doubly Twisted and Kundt spacetimes
Carlo Alberto Mantica, Luca Guido Molinari
The simple structure of doubly torqued vectors allows for a natural characterization of doubly twisted down to warped spacetimes, as well as Kundt spacetimes down to PP waves. For…
A simple characterization of doubly twisted spacetimes
Carlo Alberto Mantica, Luca Guido Molinari
In this note we characterize 1+n doubly twisted spacetimes in terms of `doubly torqued' vector fields. They extend Bang-Yen Chen's characterization of twisted and generalized Rober…
General properties of gravity vacuum solutions
Salvatore Capozziello, Carlo Alberto Mantica, Luca Guido Molinari
General properties of vacuum solutions of gravity are obtained by the condition that the divergence of the Weyl tensor is zero and . Specifically, a theorem state…
On the uniqueness of a shear-vorticity-acceleration-free velocity field in space-times
Luca Guido Molinari, Adriano Tacchini, Carlo Alberto Mantica
We prove that in space-times a velocity field that is shear, vorticity and acceleration-free, if any, is unique up to reflection, with these exceptions: generalized Robertson-Walke…
Cosmological perfect fluids in higher-order gravity
Salvatore Capozziello, Carlo Alberto Mantica, Luca Guido Molinari
We prove that in Robertson-Walker space-times (and in generalized Robertson-Walker spacetimes of dimension greater than 3 with divergence-free Weyl tensor) all higher-order gravita…
Cosmological perfect fluids in Gauss-Bonnet gravity
Salvatore Capozziello, Carlo Alberto Mantica, Luca Guido Molinari
In an -dimensional Friedmann-Robertson-Walker metric, it is rigorously shown that any analytical theory of gravity , where is the curvature scalar and $\cal G…
Perfect-fluid, generalised Robertson-Walker space-times, and Gray's decomposition
Carlo Alberto Mantica, Luca Guido Molinari, Young Jin Suh +1
We give new necessary and sufficient conditions on the Weyl tensor for generalized Robertson-Walker (GRW) space-times to be perfect-fluid space-times. For GRW space-times, we deter…
Cosmological perfect-fluids in f(R) gravity
Salvatore Capozziello, Carlo Alberto Mantica, Luca Guido Molinari
We show that an n-dimensional generalized Robertson-Walker (GRW) space-time with divergence-free conformal curvature tensor exhibits a perfect fluid stress-energy tensor for any f(…
Shear and vorticity of perfect-fluid spacetimes and the shear-free conjecture
Carlo Alberto Mantica, Luca Guido Molinari
We obtain expressions for the shear and the vorticity tensors of perfect-fluid spacetimes, in terms of the divergence of the Weyl tensor. For such spacetimes, we prove that if the…
Twisted Lorentzian manifolds, a characterization with torse-forming time-like unit vectors
Carlo Alberto Mantica, Luca Guido Molinari
Robertson-Walker and Generalized Robertson-Walker spacetimes may be characterized by the existence of a time-like unit torse-forming vector field, with other constrains. We show th…