In the framework of the AdS/CFT correspondence, we discuss exact results at weak and at strong coupling for a family of Wilson loop operators capturing a natural generalization of the quark-antiquark potential.

Non-Gaussianity in cosmology can be used as a discriminator for inflation and models of the early universe. However, the primordial signal is contaminated by intrinsic non-linearties, ubiquitous in GR. I will discuss these effects on the CMB and the cosmic shear. In particular, I will derive the CMB 3-p function generated by second-order effects at recombination, in the limit when one of the three modes is much longer than the other two and out of the horizon at recombination, and I will discuss the contamination to the primordial signal. The second part of the talk will be devoted to cosmic shear. Future lensing surveys will be nearly full-sky and reach an unprecedented depth, probing scales closer and closer to the Hubble radius. I will compute the GR effects associated to these scales, by studying the cosmic shear beyond the usual small-angle approximation. I will then discuss how these corrections contaminate to primordial non-Gaussianity.

Network research and percolation theory have been focused on the properties of a single isolated network that does not interact or depends on other networks. In reality, many real-networks interact with other networks. We present a framework for studying percolation of interacting networks. In interdependent networks, when nodes in one network fail, they cause dependent nodes in other networks to also fail. This may happen recursively and can lead to a cascade of failures. In fact, a failure of a very small fraction of nodes in one network may lead to the complete fragmentation of a system of many interdependent networks. I will present exact analytical solutions for the critical threshold and giant component of a network of n interdependent networks. For n=1 we obtain the classical known result for a single isolated network of second order percolation transition. For n>1 cascading failures occur and the transition becomes a first order. Our results for a network of n interdependent networks suggest that the classical percolation theory extensively studied in physics and mathematics in the past 60 years is only a limiting case of n=1 of a more general case of network of networks. As I will show, this general theory has many novel features that are not present in classical percolation theory. For example, analyzing complex systems as a set of interdependent networks may

alter a basic assumption that network theory has relied on: while for a single network a broader degree distribution of the network nodes results in the network being more robust to random failures, for interdependent networks, the broader the distribution is, the more vulnerable the networks become to random failure. We also show that reducing the coupling between the networks leads to a change from a first order percolation phase transition to a second order percolation transition at a critical point.

Se presenta el descubrimiento del ultra alto vacío y su impacto en el desarrollo de los grandes sistemas de vacío, especialmente los aceleradores de partículas, anillos de almacenamiento de partículas (radiación sincrotrón), y sistemas de fusión termonuclear. Entre los primeros se presentan las características y los medios de lograr presiones tan bajas como 10-12 mbar del Large Hadron Collider (Gran Colisionador de Partículas) del CERN en un sistema de vacío circular de 56 km de longitud, que permite obtener partículas con una energía de 14 TeV ! (109eV). Se describe su revolucionario sistema de vacío y el desarrollo de tecnologías muy específicas para lograr esa presión tan baja. A continuación se describen las particularidades de los anillos de almacenamiento de partículas, conocidos como Sincrotrón, como trabajan y en qué condiciones se puede obtener el ultra alto vacío necesario. Por último, se presenta la Máquina donde se pretende crear un plasma de tal temperatura que permita la fusión termonuclear, pero con problemas físico-químicos que impiden, de momento, llegar a esa temperatura.

he effect of solutes on the structure of water has been debated intensively over the past years. Typical scenarios label different ions as water structure "makers" or "breakers": this is a quite elusive definition, which has been firstly introduced in the description of the effect of solutes on the viscosity of water, and, although criticized, is still used in the current literature. In this talk we present a possible relation between the viscosity B-coefficient and a local structural property of the solution, using a combination of neutron diffraction and computer modeling.

De vegades cal aprendre a fer l´indi per a entendre el nitrur d´indi. En aquesta xerrada explicaré quins són els aspectes més interessants, des del punt de vista físic, d´aquest semiconductor, i com aquests poden ser estudiats a través de tècniques òptiques. Parlarem de fotons, de plasmons, de fonons i d´electrons, així que heu de venir per c...

While modern biology faces a data deluge of molecular and genetic information, our ability to integrate this information to make biomedically meaningful predictions at the organ or organism level is still limited, because of the difficulty of predicting the emergent properties of large ensembles of cells from the cells’ molecular signatures. For the past 15 years, we have been developing computational tools and approaches to bridge the gap between molecule and physiological outcome. Our open-source CompuCell3D modeling environment enables rapid Python-scripted specification and refinement of complex biomedical simulations that combine subcellular molecular reaction kinetics models, the physical and mechanical behaviors of cells and the longer range effects of the extracellular environment. Such simulations are much easier to disseminate, support, share, test and reuse than classical low-level-code. I will illustrate two projects using CompuCell3D, one on Choroidal neovascularization (CNV) in Age-Related Macular Degeneration (the most common cause of blindness among the elderly), the second on the factors influencing the rate of progression of solid tumors to metastatic cancers due to evolutionary selection.

Emissions potents d´ones de ràdio, un espectre visible molt semblant al d´una estrella i, en alguns casos, ràpides variacions en la lluminositat, són algunes de les característiques que defineixen els objectes als quals es va anomenar QUASARS. Aquests objectes compactes ens fan arribar una de les cançons més antigues, una cançó que ens parla de la formació i evolució de les galàxies, i també de l´evolució del mateix univers.

Les radiacions nocives, quina por! Sabíeu que hi ha físics treballant en el dia a dia de l´hospital? Fer que aquestes radiacions ajudin en la lluita contra el càncer és part d´aquesta feina. Des del diagnòstic al tractament, la Física Mèdica ens ajuda i beneficia a tots.

Quantes maneres hi ha d´omplir l´espai ordenadament i sense deixar buits? Ja sigui encaixant les rajoles de la cuina o els àtoms en la matèria, aquest problema aparentment senzill ha fet anar de corcoll a més d´un savi al llarg de la història. I just quan tot semblava resolt, apareixen uns materials que s´organitzen d´una manera "impossible". Quasicristalls: vine a descobrir la seva història i les seves propietats!