Covariant Formulation of the Invariant Measure for the Mixmaster Dynamics

We provide a Hamiltonian analysis of the Mixmaster Universe dynamics showing the covariant nature of its chaotic behavior with respect to any choice of time variable. We construct the appropriate invariant measure for the system (which relies on the existence of an ``energy-like'' constant of motion) without fixing the time gauge, i.e. the corresponding lapse function. The key point in our analysis consists of introducing generic Misner-Chitr\'e-like variables containing an arbitrary function, whose specification allows one to set up the same dynamical scheme in any time gauge.Comment: 11 pages, 1 figur

Oscillatory regime in the Multidimensional Homogeneous Cosmological Models Induced by a Vector Field

We show that in multidimensional gravity vector fields completely determine the structure and properties of singularity. It turns out that in the presence of a vector field the oscillatory regime exists in all spatial dimensions and for all homogeneous models. By analyzing the Hamiltonian equations we derive the Poincar\'e return map associated to the Kasner indexes and fix the rules according to which the Kasner vectors rotate. In correspondence to a 4-dimensional space time, the oscillatory regime here constructed overlap the usual Belinski-Khalatnikov-Liftshitz one.Comment: 9 pages, published on Classical and Quantum Gravit

Quasi-Isotropization of the Inhomogeneous Mixmaster Universe Induced by an Inflationary Process

We derive a ``generic'' inhomogeneous ``bridge'' solution for a cosmological model in the presence of a real self-interacting scalar field. This solution connects a Kasner-like regime to an inflationary stage of evolution and therefore provides a dynamical mechanism for the quasi-isotropization of the universe. In the framework of a standard Arnowitt-Deser-Misner Hamiltonian formulation of the dynamics and by adopting Misner-Chitr\`e-like variables, we integrate the Einstein-Hamilton-Jacobi equation corresponding to a ``generic'' inhomogeneous cosmological model whose evolution is influenced by the coupling with a bosonic field, expected to be responsible for a spontaneous symmetry breaking configuration. The dependence of the detailed evolution of the universe on the initial conditions is then appropriately characterized.Comment: 17 pages, no figure, to appear on PR

Arithmetical Chaos and Quantum Cosmology

In this note, we present the formalism to start a quantum analysis for the recent billiard representation introduced by Damour, Henneaux and Nicolai in the study of the cosmological singularity. In particular we use the theory of Maass automorphic forms and recent mathematical results about arithmetical dynamical systems. The predictions of the billiard model give precise automorphic properties for the wave function (Maass-Hecke eigenform), the asymptotic number of quantum states (Selberg asymptotics for PSL(2,Z)), the distribution for the level spacing statistics (the Poissonian one) and the absence of scarred states. The most interesting implication of this model is perhaps that the discrete spectrum is fully embedded in the continuous one.Comment: 35 pages, 4 figures. to be published on Classical and Quantum Gravity (scheduled for January 2009

FREEDOM Project. Scenario, requirements and first business model analysis

This deliverable is the first of FREEDOM project. It provides an outlook of the scenarios and assumptions widely shared in the wireless community when addressing femtocell deployment. It starts by providing scenarios as seen from the business perspective, and then they are further described with a more technical perspective. Both interference and mobility are addressed although from the review of foras and standardization bodies, the interference issues are more extensively considered. From these scenarios we derived a list of requirement that should be met by femto-cell systems. These requirements must drive the technical work in the other work-pacakges of FREEDOM. The report then captures the main assumptions for simulation in order to align the work from various WPs and partners around similar set of assumptions. A final section presents true business model from operator standpoint, highlighting the potential of massive femto-cell deployment.Peer ReviewedPostprint (author’s final draft

FREEDOM Project. Scenario, requirements and first business model analysis

This deliverable is the first of FREEDOM project. It provides an outlook of the scenarios and assumptions widely shared in the wireless community when addressing femtocell deployment. It starts by providing scenarios as seen from the business perspective, and then they are further described with a more technical perspective. Both interference and mobility are addressed although from the review of foras and standardization bodies, the interference issues are more extensively considered. From these scenarios we derived a list of requirement that should be met by femto-cell systems. These requirements must drive the technical work in the other work-pacakges of FREEDOM. The report then captures the main assumptions for simulation in order to align the work from various WPs and partners around similar set of assumptions. A final section presents true business model from operator standpoint, highlighting the potential of massive femto-cell deployment.Peer Reviewe

The EEE Project: status and perspectives

The Extreme Energy Events (EEE) project plans to build and use an array of cosmic ray telescopes for muon detection, distributed over the italian territory. The use of such telescopes, based on Multigap Resistive Plate Chambers (MRPC) will allow the study of cosmic ray showers and the correlation between multiple primaries producing distant showers. The project is also intended to involve high school teams in an advanced research work. The physics items which can be addressed by such array, and the present status and perspectives of the project are here discussed