401 citations · 3.5k across the 55 of their papers we have counts for
24 papers · 1 filter
Retrieving black hole information from the main Lorentzian saddle point
Cristiano Germani
One of the most striking evidences of the information loss paradox is that, according to the Hawking's calculation, the correlation functions of a test scalar field exponentially d…
Remnants in two-dimensional quantum gravity
Cristiano Germani, David Pereñiguez
In this work we consider a two-dimensional quantum black hole sourced by the trace anomaly of a conformal field theory. By using holography, we are able to prove that the black hol…
Firewalls as artefacts of inconsistent truncations of quantum geometries
Cristiano Germani, Debajyoti Sarkar
In this paper we argue that a firewall is simply a manifestation of an inconsistent truncation of non-perturbative effects that unitarize the semiclassical black hole. Namely, we s…
Massive spin-2 theories
Sarah Folkerts, Cristiano Germani, Nico Wintergerst
We give an introduction to massive spin-2 theories and the problem of their non-linear completion. We review the Boulware-Deser ghost problem and two ways to circumvent classic no-…
On the many saddle points description of quantum black holes
Cristiano Germani
Considering two dimensional gravity coupled to a CFT, we show that a semiclassical black hole can be described in terms of two Liouville theories matched at the horizon. The black…
On Ghost-free Supersymmetric Galileons
Fotis Farakos, Cristiano Germani, Alex Kehagias
We present consistent supersymmetric theories invariant under the generalization of the Galilean shift symmetry to superspace. These theories are constructed via the…
On the Covariant Galileon and a consistent self-accelerating Universe
Cristiano Germani
In this paper we show that the flat space Galilean theories with up to three scalars in the equation of motion (the quartic Galileons) are recovered in the decoupling limit of cert…
A New Class of Four-Dimensional N=1 Supergravity with Non-minimal Derivative Couplings
Fotis Farakos, Cristiano Germani, Alex Kehagias +1
In the N=1 four-dimensional new-minimal supergravity framework, we supersymmetrise the coupling of the scalar kinetic term to the Einstein tensor. This coupling, although introduce…
Introducing the Slotheon: a slow Galileon scalar field in curved space-time
Cristiano Germani, Luca Martucci, Parvin Moyassari
In this paper we define covariant Galilean transformations in curved spacetime and find all scalar field theories invariant under this symmetry. The Slotheon is a Galilean invarian…
Physics of Trans-Planckian Gravity
Gia Dvali, Sarah Folkerts, Cristiano Germani
We study the field theoretical description of a generic theory of gravity flowing to Einstein General Relativity in IR. We prove that, if ghost-free, in the weakly coupled regime s…
Relativistic Quantum Gravity at a Lifshitz Point
Cristiano Germani, Alex Kehagias, Konstadinos Sfetsos
We show that the Horava theory for the completion of General Relativity at UV scales can be interpreted as a gauge fixed theory, and it can be extended to an invariant theory under…
The Cosmological Slingshot Scenario: a Stringy Proposal for the Early Time Cosmology
Cristiano Germani, Nicolas Grandi, Alex Kehagias
In the Cosmological Slingshot Scenario, our Universe is a D3-brane that extends in the 4d noncompact directions of a warped Calabi-Yau compactification of IIB Supergravity. Early t…
On interactions of higher spin fields with gravity and branes in AdS_5
Cristiano Germani, Arabella Schelpe
We construct actions of higher spin fields interacting with gravity on AdS_5 backgrounds such that the Compton scattering amplitudes of the interaction are tree-level unitary. We t…
The Cosmological Slingshot Scenario: Myths and Facts
Cristiano Germani, Nicolas Grandi, Alex Kehagias
We generalize the Cosmological Slingshot Scenario for a Slingshot brane moving in a Klebanov-Strassler throat. We show that the horizon and isotropy problems of standard cosmology…
The Cosmological Slingshot Scenario: A Stringy Early Times Universe
Cristiano Germani, N. E. Grandi, Alex Kehagias
A cosmological model for the early time Universe is proposed. In this model, the Universe is a wandering brane moving in a warped throat of a Calabi-Yau space. A non-zero angular m…
Two-dimensional Quantum Black Holes, Branes in BTZ and Holography
Cristiano Germani, Giovanni Paolo Procopio
We solve semiclassical Einstein equations in two dimensions with a massive source and we find a static, thermodynamically stable, quantum black hole solution in the Hartle-Hawking…
Asymptotically AdS brane black holes
Christophe Galfard, Cristiano Germani, Akihiro Ishibashi
We study the possibility of having a static, asymptotically AdS black hole localized on a braneworld with matter fields, within the framework of the Randall and Sundrum scenario. W…
Cosmic Acceleration Driven by Mirage Inhomogeneities
Christophe Galfard, Cristiano Germani, Alex Kehagias
A cosmological model based on an inhomogeneous D3-brane moving in an AdS_5 X S_5 bulk is introduced. Although there is no special points in the bulk, the brane Universe has a cente…
Higher-Spin Fields in Braneworlds
Cristiano Germani, Alex Kehagias
The dynamics of higher-spin fields in braneworlds is discussed. In particular, we study fermionic and bosonic higher-spin fields in AdS_5 and their localization on branes. We find…
Gravitational collapse and black hole evolution: do holographic black holes eventually "anti-evaporate"?
Roberto Casadio, Cristiano Germani
We study the gravitational collapse of compact objects in the Brane-World. We begin by arguing that the regularity of the five-dimensional geodesics does not allow the energy-momen…
Astrophysical and Cosmological Consequences of the Dynamical Localization of Gravity
Cristiano Germani
In this thesis I review cosmological and astrophysical exact models for Randall-Sundrum-type braneworlds and their physical implications. I present new insights and show their anal…
Varying Fundamental Constants from a String-inspired Brane World Model
Cristiano Germani, Carlos F. Sopuerta
We report results on the construction of cosmological braneworld models in the context of the Einstein-Gauss-Bonnet gravity, which include the leading correction to the Einstein-Hi…
String inspired braneworld cosmology
Cristiano Germani, Carlos F. Sopuerta
We consider braneworld scenarios including the leading correction to the Einstein-Hilbert action suggested by superstring theory, the Gauss-Bonnet term. We obtain and study the com…
Stars in the braneworld
Cristiano Germani, Roy Maartens
We show that in a Randall-Sundrum II type braneworld, the vacuum exterior of a spherical star is not in general a Schwarzschild spacetime, but has radiative-type stresses induced b…