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P. Valtancoli

Publications and source records attributed to P. Valtancoli.

At least 19 recordsLinked to original sources
arXiv2023

Euclidean black holes and spin connection

The Euclidean method is usually discussed in the context of the metric avoiding the typical delta of the conical singularity. We introduce a new way to calculate the Hawking temperature using the vierbein and spin connection. The conical singularity is seen globally through an effect on parallel transport, the so called holonomy of the spin connection. The period of the Euclidean time is calculated requiring that the holonomy of the spin connection is trivial at the event horizon.

gr-qc↗
arXiv2022

Translation in momentum space and minimal length

We show that in presence of the Snyder algebra the notion of translation in momentum space is modified to a formula similar to the relativistic addition of velocities. These results confirm the strict connection between Snyder algebra and the Lorentz group.

hep-th↗
arXiv2018

Exactly solvable f(R) inflation

We show that adding a cosmological constant term to the Starobinsky model, it can be solved exactly without using the slow-roll approximation.

gr-qc↗
arXiv2018

Remarks on cosmological gravitational waves

We study the propagation of a gravitational wave in an Ads spacetime. We find that, in presence of the cosmological constant, the graviton mass cannot be measured with higher precision than the square root of the cosmological constant.

gr-qc↗
arXiv2016

Scalar field conformally coupled to a charged BTZ black hole

We study the Klein-Gordon equation of a scalar field conformally coupled to a charged BTZ black hole. The background metric is obtained by coupling a non-linear and conformal invariant Maxwell field to (2+1) gravity. We show that the radial part is generally solved by a Heun function and, in the pure gravity limit, by a hypergeometric function.

gr-qc↗
arXiv2015

Path integral and noncommutative poisson brackets

We find that in presence of noncommutative poisson brackets the relation between Lagrangian and Hamiltonian is modified. We discuss this property by using the path integral formalism for non-relativistic systems. We apply this procedure to the harmonic oscillator with a minimal length.

hep-th↗
arXiv2015

Hawking radiation for a scalar field conformally coupled to an AdS black hole

The decomposition in normal modes of a scalar field conformally coupled to an AdS black hole leads to a Heun equation with simple coefficients thanks to conformal invariance. By applying the Damour-Ruffini method we can relate the critical exponent of the radial part at the horizon surface to the Hawking radiation of scalar particles.

gr-qc↗
arXiv2012

Remarks on the harmonic oscillator with a minimal position uncertainty

We show that this problem gives rise to the same differential equation of a well known potential of ordinary quantum mechanics. However there is a subtle difference in the choice of the parameters of the hypergeometric function solving the differential equation which changes the physical discussion of the spectrum.

hep-th↗
arXiv2008

Extended BRS symmetry in topological field theories

A class of topological field theories like the $BF$ model and Chern-Simons theory, when quantized in the Landau gauge, enjoys the property of invariance under a vector supersymmetry, which is responsible for their finiteness. We introduce a new type of gauge fixing which makes these theories invariant under an extended $BRS$ symmetry, containing a new type of field, the ghost of diffeomorphisms. The presence of such an extension is naturally related to the vector supersymmetry discussed before.

hep-th↗
arXiv2006

Entanglement entropy and 2d black holes

We explore the method of entanglement entropy applied to 2d black holes. We introduce a solvable model of a real scalar field with finite volume and lattice spacing in terms of $N$ coupled mechanical oscillators and compute its entanglement entropy in many cases. The large $N$ limit of this scheme, with finite lattice spacing, should reproduce the Bekenstein-Hawking formula for black hole entropy.

hep-th↗
arXiv2005

Non-abelian instantons on a fuzzy four-sphere

We study the compatibility between the $BPST SU(2)$ instanton and the fuzzy four-sphere algebra. By using the projective module point of view as an intermediate step, we are able to identify a non-commutative solution of the matrix model equations of motion which minimally extends the SU(2) instanton solution on the classical sphere $S^4$. We also propose to extend the non-trivial second Chern class with the five-dimensional noncommutative Chern-Simons term.

hep-th↗
arXiv2005

U(2) projectors and 't Hooft-Polyakov monopoles on a fuzzy sphere

We show how to generalize our method, based on projective modules and matrix models, which enabled us to derive noncommutative monopoles on a fuzzy sphere, to the non-abelian case, recovering known results in literature. We then discuss a possible candidate for deforming the commutative Chern class to the non-commutative case.

hep-th↗