Ultra High Energy Cosmic Rays from charged black holes. A new theoretical possibility?

In General Relativity, there is a new field of activity concerning the study of charged stars. In a recent paper, Ray et al. have shown the possibility that the collapse of a charged star could form a charged black hole before all the charge leaves the system. In this field of view we propose a new model for UHECR and we will show that it is possible to accelerate cosmic rays up to EeV. In this talk we will compute the UHECR flux, the charged black hole density and the energy spectrum associated with them in order to reproduce experimental data. We will see that we need only a small number of these hidden sources in order to account for observed UHECR properties and we will study the limits on charge and mass of black holes.Comment: 4 pages, 2 figure

Multiplying a Gaussian Matrix by a Gaussian Vector

We provide a new and simple characterization of the multivariate generalized Laplace distribution. In particular, this result implies that the product of a Gaussian matrix with independent and identically distributed columns by an independent isotropic Gaussian vector follows a symmetric multivariate generalized Laplace distribution

Building Ethically Bounded AI

The more AI agents are deployed in scenarios with possibly unexpected situations, the more they need to be flexible, adaptive, and creative in achieving the goal we have given them. Thus, a certain level of freedom to choose the best path to the goal is inherent in making AI robust and flexible enough. At the same time, however, the pervasive deployment of AI in our life, whether AI is autonomous or collaborating with humans, raises several ethical challenges. AI agents should be aware and follow appropriate ethical principles and should thus exhibit properties such as fairness or other virtues. These ethical principles should define the boundaries of AI's freedom and creativity. However, it is still a challenge to understand how to specify and reason with ethical boundaries in AI agents and how to combine them appropriately with subjective preferences and goal specifications. Some initial attempts employ either a data-driven example-based approach for both, or a symbolic rule-based approach for both. We envision a modular approach where any AI technique can be used for any of these essential ingredients in decision making or decision support systems, paired with a contextual approach to define their combination and relative weight. In a world where neither humans nor AI systems work in isolation, but are tightly interconnected, e.g., the Internet of Things, we also envision a compositional approach to building ethically bounded AI, where the ethical properties of each component can be fruitfully exploited to derive those of the overall system. In this paper we define and motivate the notion of ethically-bounded AI, we describe two concrete examples, and we outline some outstanding challenges.Comment: Published at AAAI Blue Sky Track, winner of Blue Sky Awar

The welfare state and new challenge from the back door

1980s in Germany, Britain, France and Italy suggests a convergent and consistent process of homogenisation driven chiefly by institutional mimetic isomorphism. This new 'organisational settlement' is increasingly shaped by the structural autonomisation of individual service delivery units. This paper argues that, when organisational autonomy becomes normatively sanctioned, that this increases the likelihood of its adoption, even in the face of different institutional conditions and welfare regimes. Hence, the paper is foremost concerned with explaining similarities and decreasing variance across countries and across sectors, and with accounting for the main driver of this homogenisation process. Why would different organisational fields across countries and welfare regimes adopt similar structures, in light of inconclusive evidence of economic efficiency gains? The convergence of the organisational settlement of the welfare delivery state is not only driven by economic globalisation or efficiency linked to performance, but primarily by the political demand to find new sources of legitimation in an age of increasing displacement of political authority to managers. The paper is structured in three main parts. First, it revisits the theory of organisational isomorphism by its application to the new patterns of change of welfare delivery. Secondly, it discusses the reform trajectories of autonomisation in schooling and hospital care in Britain, in comparative terms with France and Italy. Thirdly, it concentrates on Germany and it establishes empirically how this case does no longer fit the characterisation of 'immobilisme', especially in the health care sector. Lastly, the wider implications of organisational homogenisation for the TRUDI constellation are discussed. --

Ground-State Analysis for an Exactly Solvable Coupled-Spin Hamiltonian

We introduce a Hamiltonian for two interacting $su(2)$ spins. We use a mean-field analysis and exact Bethe ansatz results to investigate the ground-state properties of the system in the classical limit, defined as the limit of infinite spin (or highest weight). Complementary insights are provided through investigation of the energy gap, ground-state fidelity, and ground-state entanglement, which are numerically computed for particular parameter values. Despite the simplicity of the model, a rich array of ground-state features are uncovered. Finally, we discuss how this model may be seen as an analogue of the exactly solvable $p+ip$ pairing Hamiltonian

El arte y los nuevos medios en Italia Title: Art and New Media in Italy

Maria Grazia Mattei (1950-), Italian expert in new communications technology, founder of MGM Digital Communication, with remarks by artist Fabrizio Plessi.Abstract: Maria Grazia Mattei (1950 -), experta italiana en la nueva tecnología de las comunicaciones, fundadora de MGM Digital Communication, con notas del artista Fabrizio Plessi.Culture & Arts, Cultural Center Encuentros Nro. 45 Maria Grazia Mattei Art and New Media in Italy

Field patterns: a new type of wave with infinitely degenerate band structure

Field pattern materials (FP-materials) are space-time composites with PT-symmetry in which the one-dimensional- spatial distribution of the constituents changes in time in such a special manner to give rise to a new type of waves, which we call field pattern waves (FP-waves) [G. W. Milton and O. Mattei, Proc. R. Soc. A 473, 20160819 (2017), O. Mattei and G. W. Milton, arXiv:1705.00539 (2017)]. Specifically, due to the special periodic space-time geometry of these materials, when an instantaneous disturbance propagates through the system, the branching of the characteristic lines at the space-time interfaces between phases does not lead to a chaotic cascade of disturbances but concentrates on an orderly pattern of disturbances: this is the field pattern. By applying Bloch-Floquet theory we find that the dispersion diagrams associated with these FP-materials are infinitely degenerate: associated with each point on the dispersion diagram is an infinite space of Bloch functions, a basis for which are generalized functions each concentrated on a field pattern, paramaterized by a variable that we call the launch parameter. The dynamics separates into independent dynamics on the different field patterns, each with the same dispersion relation.Comment: 8 pages, 4 figure