L’any 2002 es va fer el I Workshop, amb una bona resposta d’inscripció internacional. Per a aquest II Barcelona Workshop es pretén internacionalitzar més la procedència dels ponents i plantejar temes a un nivell científic capdavanter. El programa s’ha elaborat amb aquesta intenció, però al mateix temps hi inclourà diverses presentacions de professorat dels departaments de Física Aplicada i Òptica i d’Electrònica i del nostre entorn científic proper. Tindrà lloc els dies 13 i 14 d’octubre.

The neutrino, the lightest and most weakly interacting fermion of the Standard Model, has revealed itself as the messenger of the most exciting news of the last decade in particle physics: there is Physics Beyond the Standard Model. All this thanks to the quantum-mechanical phenomenon of flavour oscillations which is intrinsically connected to the question of neutrino mass and which has been observed in a variety of physical situations. Neutrinos have also an important role in Astrophysics and Cosmology as well as in the study of our own planet. Indeed the possibility of doing tomography of the Earth's structure using a high energy cosmic neutrino beam has been extensively studied since it was first suggested more than twenty five years ago.In this talk I will first review the evidence for neutrino mass from existing experiments. I will then briefly comment what we can learn on more exotic forms of new physics and on the solar model from this data. In the second part I will review the different approaches to neutrino Earth tomography using high energy neutrinos. I will point out their limitations. Finally I will present our most recent observation that with the advent of second-generation kilometer-scale neutrino detectors, the idea of studying the internal structure of the Earth may be revived using atmospheric neutrinos.

In this seminar I will review the ``state of the art'' of the calculations of the nuclear matrix elements (NME) of the neutrinoless double beta decays for the nuclei 48Ca, 76Ge, 82Se, 124Sn, 128Te, 130Te and 136Xe in the framework of the Interacting Shell Model (ISM), and compare them with the NME's obtained using the Quasi-particle RPA approach (QRPA). I will also discuss the effect of the competition between the pairing and quadrupole correlations in the value of these NME's. In particular I will show that, as the difference in deformation between parent and grand daughter grows, the NME's of both the neutrinoless and the two neutrino modes decrease rapidly.

The use of entanglement renormalization in the presence of scale invariance is investigated. We explain how to compute an accurate approximation of the critical ground state of a lattice model, and how to evaluate local observables, correlators and critical exponents. Our results unveil a precise connection between the multi-scale entanglement renormalization ansatz and conformal field theory (CFT).Given a critical Hamiltonian on the lattice, this connection can be exploited to extract most of the conformal data of the CFT that describes the model in the continuum limit.

Primer seminari en anglés adreçat a alumnes de primer cicle: "The Unsettled Sun: Space Storms"The lecture will give an overview of solar eruptions and space weather. Physical conditions in the near-Earth space change as the activity of the Sun varies. During periods of high solar activity, the Sun frequently erupts. From time to time, such eruptions are directed towards the Earth generating space storms that, in turn, originate bright auroras. The strong electric currents related to the auroras can cause disturbances in the electric grids and telecommunication systems, and the charged particles of the solar eruptions can cause malfunctions or even loss of the Earth-orbiting satellites.

Neutron experiments provide a unique opportunity in some cases to probe extra short-range interactions. We will consider the most sensitive experiments. Spin-dependent (axion-like) interactions in the distance range of 10^(-6)-10^(-3) m are best constrained from the observation of the gravitationally-bound quantum states of neutrons. Further significant progress is expected in the new-generation experiment GRANIT on resonance transitions between the gravitationally bound quantum states of neutrons. Spin-independent short range forces in the distance range of 10^(-12)-10^(-8) m are best constrained from the neutron scattering experiments. One could probably extend the distance range for such forces to sub-microns using centrifugal quantum states of neutrons, and/or to microns using GRANIT.

Black holes are perhaps the most fascinating astrophysical objects we know about. An original prediction of the Einstein field equations, they are now thought to play an essential role in our image of the universe, from small to large scales. In this talk I will briefly review the main features of black hole physics and I will discuss the evidence supporting the existence of these objects. Then, I will extend on their multiple astrophysical manifestations, from stellar systems to the central engines a quasars.

In the last decade, a combination of high sensitivity and spatial resolution observations in the extragalactic domain, and of coordinated multi-wavelength campaigns on galactic objects have revolutionized our understanding of black holes astrophysics on all mass scales. This has led to substantial progress towards super-unification schemes for active galactic nuclei, in which the large variety of different AGN classes can be classified based on fundamental physical parameters only, such as mass, accretion rate and kinetic energy output. I will describe the constraints available from a study of AGN evolution models on the growth of the SMBH population in the two main 'modes' observed (kinetic- and radiatively-dominated, respectively). SMBH always show a very broad accretion rate distribution, and I'll discuss the consequences of this fact for our understanding of observed AGN fractions in galaxies. I will show how SMBH mass function evolves anti-hierarchically, i.e. the most massive holes grew earlier and faster than less massive ones, and I will also derive tight constraints on the average radiative efficiency of AGN. Finally, constraints on the redshift evolution of the AGN kinetic luminosity function will be discussed and compared with the radiative output of the evolving SMBH population, thus providing a robust physical framework for phenomenological models of AGN feedback within structure formation.