Astrophysical Production of Microscopic Black Holes in a Low Planck-scale World

In the framework of brane-world models lowering the Planck scale to the TeV range, it has recently been pointed out that small black holes could be formed at particle colliders or by neutrinos interactions in the atmosphere. This article aims at reviewing other places and epochs where microscopic black holes could be formed : the interstellar medium and the early Universe. The related decay channels and the propagation of the emitted particles are studied to conclude that, in spite of the large creation rate for such black holes, the amount of produced particles do not conflict with experimental data. This shows, from the astronomical viewpoint, that models with large extra dimensions making the gravity scale much lower are compatible with observations.Comment: To appear in Ap

Hilbert-Polya conjecture and Generalized Riemann Hypothesis

Extending a classical integral representation of Dirichlet L-functions associated to a non trivial primitive character we define associated functions B(y,z) which are eigenfunction of a Hermitian operator H. The eigenvalues are the imaginary parts of the L-functions zeros. We prove that if s is a non trivial zero of such a Dirichlet L-function with Re(s)<1/2, then: - the associated eigenfunction B(z,y) is square integrable. - the operator H is "Hermitian" for this function: =. We deduce from this (using the idea of Hilbert-Polya and finding a contradiction) the Generalized Riemann Hypothesis: the non trivial zeros of a Dirichlet L-function lie on the critical line Re(s)=1/2. This results correspond to a weak form of the Hilbert-Polya conjecture (as for Re(s)=1/2 the eigenfunctions presented here are not square integrable).Comment: 16 Pages. Article withdraw as function Bs presented is not square integrable as claimed. (Mistake is on one sub-domain considered: function I2 near y=0

World-making with extended gravity black holes for cosmic natural selection in the multiverse scenario

Physics is facing contingency. Not only in facts but also in laws (the frontier becoming extremely narrow). Cosmic natural selection is a tantalizing idea to explain the apparently highly improbable structure of our Universe. In this brief note I will study the creation of Universes by black holes in -string inspired- higher order curvature gravity.Comment: 5 pages, 1 figure. Proceedings of the Eleventh Marcel Grossmann Meeting on General Relativity, edited by H. Kleinert, R.T. Jantzen and R. Ruffini, World Scientific, Singapore, 200

Testing different approaches to quantum gravity with cosmology: An overview

Among the available quantum gravity proposals, string theory, loop quantum gravity, non-commutative geometry, group field theory, causal sets, asymptotic safety, causal dynamical triangulation, emergent gravity are among the best motivated models. As an introductory summary to this special issue of Comptes Rendus Physique, I explain how those different theories can be tested or constrained by cosmological observations.Comment: Invited introductory article for a special issue of Comptes Rendus Physiqu

Loop quantum gravity and the CMB: toward pre-Big Bounce cosmology

This brief article sums up the possible imprints of loop quantum gravity effects on the cosmological microwave background. We focus on semi-classical terms and show that "Big Bounce" corrections, together with the "pre Big Bounce" state, could modify the observed spectrum.Comment: Proceedings of the 12th Marcel Grossman Meeting on General Relativity. 3 pages, no figur

Testing the Everett Interpretation of Quantum Mechanics with Cosmology

In this brief note, we argue that contrarily to what is still often stated, the Everett many-worlds interpretation of quantum mechanics is not in principle impossible to test. It is actually not more difficult (but not easier either) to test than most other kinds of multiverse theories. We also remind why multiverse scenarios can be falsified.Comment: 5 page

Antimatter from primordial black holes

Antiprotons and antideuterons are considered as probes to look for primordial black holes in our Galaxy. I give a brief overview of the latest developments on the subject.Comment: proceedings of the XIVth Rencontres de Blois : Matter-Antimatter Asymmetr