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S. Mignemi

Publications and source records attributed to S. Mignemi.

At least 73 records · Page 4Linked to original sources
arXiv2007

Doubly Special Relativity and Finsler geometry

We discuss the recent proposal of implementing Doubly Special Relativity in configuration space by means of Finsler geometry. Although this formalism leads to a consistent description of the dynamics of a particle, it does not seem to give a complete description of the physics. In particular, the Finsler line element is not invariant under the deformed Lorentz transformations of Doubly Special Relativity. We study in detail some simple applications of the formalism.

gr-qc↗
arXiv2007

Asymptotic properties of black hole solutions in dimensionally reduced Einstein-Gauss-Bonnet gravity

We study the asymptotic behavior of the spherically symmetric solutions of the system obtained from the dimensional reduction of the six-dimensional Einstein- Gauss-Bonnet action. We show that in general the scalar field that parametrizes the size of the internal space is not trivial, but nevertheless the solutions depend on a single parameter. In analogy with other models containing Gauss-Bonnet terms, naked singularities are avoided if a minimal radius for the horizon is assumed.

gr-qc↗
arXiv2005

Global properties of charged dilatonic Gauss-Bonnet black holes

We study the phase space of the spherically symmetric solutions of Einstein-Maxwell-Gauss-Bonnet system nonminimally coupled to a scalar field and prove the existence of solutions with unusual asymptotics in addition to asymptotically flat ones. We also find new dyonic solutions of dilatonic Einstein-Maxwell theory.

gr-qc↗
arXiv2005

A spacetime realization of kappa-Poincare algebra

We study a Hamiltonian realization of the phase space of kappa-Poincare algebra that yields a definition of velocity consistent with the deformed Lorentz symmetry. We are also able to determine the laws of transformation of spacetime coordinates and to define an invariant spacetime metric, and discuss some possible experimental consequences.

gr-qc↗
arXiv2005

Global properties of dilatonic Gauss-Bonnet black holes

We study the phase space of the spherically symmetric solutions of Einstein Gauss-Bonnet system nonminimally coupled to a scalar field and show that in four dimensions the only regular black hole solutions are asymptotically flat

gr-qc↗
arXiv2005

Two-dimensional static black holes with pointlike sources

We study the static black hole solutions of generalized two-dimensional dilaton-gravity theories generated by pointlike mass sources, in the hypothesis that the matter is conformally coupled. We also discuss the motion of test particles. Due to conformal coupling, these follow the geodesics of a metric obtained by rescaling the canonical metric with the dilaton.

gr-qc↗
arXiv2004

Multi-scalar black holes with contingent primary hair: Mechanics and stability

We generalize a class of magnetically charged black holes holes non-minimally coupled to two scalar fields previously found by one of us [gr-qc/9910041] to the case of multiple scalar fields. The black holes possess a novel type of primary scalar hair, which we call a contingent primary hair: although the solutions possess degrees of freedom which are not completely determined by the other charges of the theory, the charges necessarily vanish in the absence of the magnetic monopole. Only one constraint relates the black hole mass to the magnetic charge and scalar charges of the theory. We obtain a Smarr-type thermodynamic relation, and the first law of black hole thermodynamics for the system. We further explicitly show in the two-scalar-field case that, contrary to the case of many other hairy black holes, the black hole solutions are stable to radial perturbations.

hep-th↗
arXiv2004

Solutions of deformed three-dimensional gravity

We investigate the gauging of a three-dimensional deformation of the anti-de Sitter algebra, which accounts for the existence of an invariant energy scale. By means of the Poisson sigma model formalism, we obtain explicit solutions of the field equations, which reduce to the BTZ black hole in the undeformed limit.

hep-th↗
arXiv2003

Entropy bounds in two dimensions

We discuss entropy bounds for a class of two-dimensional gravity models. While the Bekenstein bound can be proved to hold in general for weakly gravitating matter, the analogous of the holographic bound is not universal, but depends on the specific model considered

hep-th↗
arXiv2003

On the definition of velocity in theories with two observer-independent scales

We argue that a consistent definition of the velocity of a particle in generalizations of special relativity with two observer-independent scales should be independent from the mass of the particle. This request rules out the definition $v_i=\partial p_0/\partial p_i$, but allows for other definitions proposed in the literature.

hep-th↗
arXiv2002

Two-dimensional gravity with an invariant energy scale

We investigate the gauging of a two-dimensional deformation of the Poincare algebra, which accounts for the existence of an invariant energy scale. The model describes 2D dilaton gravity with torsion. We obtain explicit solutions of the field equations and discuss their physical properties.

hep-th↗
arXiv2002

Cosmology of the Jackiw-Teitelboim model

We investigate the cosmology of the two-dimensional Jackiw-Teitelboim model. Since the matter coupling is not defined uniquely, we consider two possible choices. The dilaton field plays an important role in the discussion of the properties of the solutions. In particular, the possibility of universes having a finite initial size emerges.

gr-qc↗
arXiv2002

Two-dimensional dS/CFT correspondence

We investigate de Sitter/conformal field theory (dS/CFT) correspondence in two dimensions. We define the conserved mass of de Sitter spacetime and formulate the correspondence along the lines of anti-de Sitter/conformal field theory duality. Asymptotic symmetry group, mass, and central charge of de Sitter spacetime are equal to those of anti-de Sitter spacetime. The entropy of two-dimensional de Sitter spacetime is evaluated by applying Cardy formula. We calculate the boundary correlators induced by the propagation of the dilaton in two-dimensional de Sitter space. Although the dilaton is a tachyonic perturbation in the bulk, boundary conformal correlators have positive dimension.

hep-th↗