10 papers
Cosmological extra dimensions can mimic dark matter II. Growth of cosmological structures
Mattia Villani
This is the second paper of this series in which we prove we can do without dark matter using spacetime with extra dimensions compactified to a hypersphere with radius R. Here we p…
Gravitational lensing in a spacetime with extra dimensions
Mattia Villani
This is the fourth paper of a series in which we consider the possibility to use cosmological extra dimensions to explain the accelerated expansion of the Universe and the rotation…
Cosmological extra dimensions can mimic dark energy
Mattia Villani
We present a simple model of a higher dimensional spacetime in which the 4d submanifold is a FLRW metric, while the extra dimensions are compactified to a hypersphere. We calculate…
Cosmological extra dimensions can mimic dark matter I. Dark matter in galaxies
Mattia Villani
We present a simple model with a n + 4-dimensional metric with compactified extra dimensions with a space dependent radius R. We show that changes in the profile of R are sourced b…
Gravitational waves from a binary source in higher dimensional spacetime with compactified extra dimensions
Mattia Villani
We consider the emission of gravitational waves (GW) from a compact binary in a spacetime with compactified extra dimensions. We solve the homogeneous and non-homogeneous wave equa…
Electromagnetic emission from a black-to-white hole transition -- Photospheric emission
Mattia Villani
We calculate the gamma ray emission from a black-to-white hole transition. We put forward a model for the prompt emission phase, based on the photospheric emission model with the u…
Quasi-normal modes of a multi-dimensional rotating Kerr black hole
Mattia Villani
The aim of this paper is to present a general way to calculate quasi-normal modes (QNM) of the Teukolsky equation for higher dimensional (d > 4) Kerr spacetime with compactified ex…
Black to white hole transition as a change of the topology of the event horizon
Mattia Villani
We prove that the black to white hole transition theorized in several papers can be described as a change in the topology of the event horizon. We also show, using the theory of co…
Semi-analytical and numerical solutions to Teukolsky equations for large fermion mass over black hole mass ratio
Mattia Villani
In a recent paper, we have studied the Teukolsky equations for fermions with mass and rotating black hole of mass . There, we have studied two cases: $\tilde{m}_e=m_…
Perturbative and semi-analytical solutions to Teukolsky equations for massive fermions
Mattia Villani
In this work, we aim at solving the Teukolsky equations for a fermion with mass in the presence of a rotating black hole with mass . We consider two different regime…