Discovering the manifold facets of a square integrable representation: from coherent states to open systems

Group representations play a central role in theoretical physics. In particular, in quantum mechanics unitary --- or, in general, projective unitary --- representations implement the action of an abstract symmetry group on physical states and observables. More specifically, a major role is played by the so-called square integrable representations. Indeed, the properties of these representations are fundamental in the definition of certain families of generalized coherent states, in the phase-space formulation of quantum mechanics and the associated star product formalism, in the definition of an interesting notion of function of quantum positive type, and in some recent applications to the theory of open quantum systems and to quantum information.Comment: 13 page

Measurements of Electroweak Top Production at the LHC

The production of a single top quark at LHC may occur through charged-current electroweak interactions, i.e. via three different processes: the s-channel exchange of a virtual W boson, the t-channel exchange of a virtual W boson and the associated production of a top quark and a W boson (tW). In this paper a review of the measurements of the single-top production made both at ATLAS and CMS will be shown.Comment: Proceedings of CKM 2012, the 7th International Workshop on the CKM Unitarity Triangle, University of Cincinnati, USA, 28 September - 2 October 201

Reasoning about Knowledge and Strategies under Hierarchical Information

Two distinct semantics have been considered for knowledge in the context of strategic reasoning, depending on whether players know each other's strategy or not. The problem of distributed synthesis for epistemic temporal specifications is known to be undecidable for the latter semantics, already on systems with hierarchical information. However, for the other, uninformed semantics, the problem is decidable on such systems. In this work we generalise this result by introducing an epistemic extension of Strategy Logic with imperfect information. The semantics of knowledge operators is uninformed, and captures agents that can change observation power when they change strategies. We solve the model-checking problem on a class of "hierarchical instances", which provides a solution to a vast class of strategic problems with epistemic temporal specifications on hierarchical systems, such as distributed synthesis or rational synthesis

Limit theorems for number of diffusion processes which did not absorb by boundaries

We have random number of independent diffusion processes with absorption on boundaries in some region at initial time $t=0$. The initial numbers and positions of processes in region is defined by Poisson random measure. It is required to estimate of number of the unabsorbed processes for the fixed time \~$\tau>0$. The Poisson random measure depends on $\tau$ and $\tau\to\infty$

Star products: a group-theoretical point of view

Adopting a purely group-theoretical point of view, we consider the star product of functions which is associated, in a natural way, with a square integrable (in general, projective) representation of a locally compact group. Next, we show that for this (implicitly defined) star product explicit formulae can be provided. Two significant examples are studied in detail: the group of translations on phase space and the one-dimensional affine group. The study of the first example leads to the Groenewold-Moyal star product. In the second example, the link with wavelet analysis is clarified.Comment: 42 pages; conclusions added; a few references adde

Current Status and Perspectives of Cosmic Microwave Background Observations

Measurements of the cosmic microwave background (CMB) radiation provide a unique opportunity for a direct study of the primordial cosmic plasma at redshift z ~1000. The angular power spectra of temperature and polarisation fluctuations are powerful observational objectives as they encode information on fundamental cosmological parameters and on the physics of the early universe. A large number of increasingly ambitious balloon-borne and ground-based experiments have been carried out following the first detection of CMB anisotropies by COBE-DMR, probing the angular power spectrum up to high multipoles. The recent data from WMAP provide a new major step forward in measurements percision. The ESA mission Planck Surveyor, to be launched in 2007, is the third-generation satellite devoted to CMB imaging. Planck is expected to extract the full cosmological information from temperature anisotropies and to open up new fronteers in the CMB field.Comment: 6 pages, 1 figure, to appear in "Proc of International Symposium on Plasmas in the Laboratory and in the Universe: new insights and new challenges", September 16-19, 2003, Como, Ital

Survey of Machine Learning Techniques for Malware Analysis

Coping with malware is getting more and more challenging, given their relentless growth in complexity and volume. One of the most common approaches in literature is using machine learning techniques, to automatically learn models and patterns behind such complexity, and to develop technologies for keeping pace with the speed of development of novel malware. This survey aims at providing an overview on the way machine learning has been used so far in the context of malware analysis. We systematize surveyed papers according to their objectives (i.e., the expected output, what the analysis aims to), what information about malware they specifically use (i.e., the features), and what machine learning techniques they employ (i.e., what algorithm is used to process the input and produce the output). We also outline a number of problems concerning the datasets used in considered works, and finally introduce the novel concept of malware analysis economics, regarding the study of existing tradeoffs among key metrics, such as analysis accuracy and economical costs