404 citations · 3.5k across the 37 of their papers we have counts for
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Degenerate Horava gravity
Enrico Barausse, Marco Crisostomi, Stefano Liberati +1
Horava gravity breaks Lorentz symmetry by introducing a dynamical timelike scalar field (the khronon), which can be used as a preferred time coordinate (thus selecting a preferred…
Rotating Black Holes in Higher Order Gravity
Christos Charmousis, Marco Crisostomi, Ruth Gregory +1
We develop a new technique for finding black hole solutions in modified gravity that have "stealth" hair, i.e., hair whose only gravitational effect is to tune the cosmological con…
Cosmological evolution in DHOST theories
Marco Crisostomi, Kazuya Koyama, David Langlois +2
In the context of Degenerate Higher-Order Scalar-Tensor (DHOST) theories, we study cosmological solutions and their stability properties. In particular, we explicitly illustrate th…
Beyond Lovelock gravity: Higher derivative metric theories
Marco Crisostomi, Karim Noui, Christos Charmousis +1
We consider theories describing the dynamics of a four-dimensional metric, whose Lagrangian is diffeomorphism invariant and depends at most on second derivatives of the metric. Imp…
Higher Derivative Field Theories: Degeneracy Conditions and Classes
Marco Crisostomi, Remko Klein, Diederik Roest
We provide a full analysis of ghost free higher derivative field theories with coupled degrees of freedom. Assuming the absence of gauge symmetries, we derive the degeneracy condit…
Degenerate higher order scalar-tensor theories beyond Horndeski up to cubic order
Jibril Ben Achour, Marco Crisostomi, Kazuya Koyama +3
We present all scalar-tensor Lagrangians that are cubic in second derivatives of a scalar field, and that are degenerate, hence avoiding Ostrogradsky instabilities. Thanks to the e…
Extended Scalar-Tensor Theories of Gravity
Marco Crisostomi, Kazuya Koyama, Gianmassimo Tasinato
We study new consistent scalar-tensor theories of gravity recently introduced by Langlois and Noui with potentially interesting cosmological applications. We derive the conditions…
Horndeski: beyond, or not beyond?
Marco Crisostomi, Matthew Hull, Kazuya Koyama +1
Determining the most general, consistent scalar tensor theory of gravity is important for building models of inflation and dark energy. In this work we investigate the number of de…
New Branches of Massive Gravity
Denis Comelli, Marco Crisostomi, Kazuya Koyama +2
The basic building block for Lorentz invariant and ghost free massive gravity is the square root of the combination , where is the inverse of the physical metri…
Perturbations in Massive Gravity Cosmology
Marco Crisostomi, Denis Comelli, Luigi Pilo
We study cosmological perturbations for a ghost free massive gravity theory formulated with a dynamical extra metric that is needed to massive deform GR. In this formulation FRW ba…
Spherically Symmetric Solutions in Ghost-Free Massive Gravity
D. Comelli, M. Crisostomi, F. Nesti +1
Recently, a class of theories of massive gravity has been shown to be ghost-free. We study the spherically symmetric solutions in the bigravity formulation of such theories. In gen…
FRW Cosmology in Ghost Free Massive Gravity
D. Comelli, M. Crisostomi, F. Nesti +1
We study FRW homogeneous cosmological solutions in the recently found ghost free massive gravity. In previous works it was shown that when the additional extra metric, needed to ge…
Finite Energy of Black Holes in Massive Gravity
Denis Comelli, Marco Crisostomi, Fabrizio Nesti +1
In GR the static gravitational potential of a self-gravitating body goes as 1/r at large distances and any slower decrease leads to infinity energy. We show that in a class of four…