arXiv subjects

C. Corda

Publications and source records attributed to C. Corda.

22 records · Page 2Linked to original sources

arXiv2013

Effective state, Hawking radiation and quasi-normal modes for Kerr black holes

The non-strictly continuous character of the Hawking radiation spectrum generates a natural correspondence between Hawking radiation and black hole (BH) quasi-normal modes (QNM). In this work, we generalize recent results on this important issue to the framework of Kerr BHs (KBH). We show that also for the KBH, QNMs can be naturally interpreted in terms of quantum levels. Thus, the emission or absorption of a particle is in turn interpreted in terms of a transition between two different levels. At the end of the paper, we also generalize some concepts concerning the "effective state" of a KBH.

gr-qc↗

arXiv2011

Farewell to black hole horizons and singularities?

We consider the fundamental issues which dominate the question about the existence or non-existence of black hole horizons and singularities from both of the theoretical and observational points of view, and discuss some of the ways that black hole singularities can be prevented from forming at a classical level, i.e. without arguments of quantum gravity. In this way, we argue that black holes could have a different nature with respect the common belief. In fact, even remaining very compact astrophysics objects, they could be devoid of horizons and singularities. Our analysis represents a key point within the debate on the path to unification of theories. As recently some scientists partially retrieved the old Einstein's opinion that quantum mechanics has to be subjected to a more general deterministic theory, a way to find solutions to the problem of black hole horizons and singularities at a semi-classical level, i.e. without discussions of quantum gravity, becomes a fundamental framework.

gr-qc↗

arXiv2010

Phenomenology of the Lense-Thirring effect in the Solar System

Recent years have seen increasing efforts to directly measure some aspects of the general relativistic gravitomagnetic interaction in several astronomical scenarios in the solar system. After briefly overviewing the concept of gravitomagnetism from a theoretical point of view, we review the performed or proposed attempts to detect the Lense-Thirring effect affecting the orbital motions of natural and artificial bodies in the gravitational fields of the Sun, Earth, Mars and Jupiter. In particular, we will focus on the evaluation of the impact of several sources of systematic uncertainties of dynamical origin to realistically elucidate the present and future perspectives in directly measuring such an elusive relativistic effect.

gr-qc↗

arXiv2010

Interferometer Response to Scalar Gravitational Waves

It was recently suggested that the magnetic component of Gravitational Waves (GWs) is relevant in the evaluation of frequency response functions of gravitational interferometers. In this paper we extend the analysis to the magnetic component of the scalar mode of GWs which arise from scalar-tensor gravity theory. In the low-frequency approximation, the response function of ground-based interferometers is calculated. The angular dependence of the electric and magnetic contributions to the response function is discussed. Finally, for an arbitrary frequency range, the proper distance between two test masses is calculated and its usefulness in the high-frequency limit for space-based interferometers is briefly considered.

gr-qc↗