Conferencia
Data Science in Fundamental Physics and the bridge to industry
Data Science is the art of analyzing data sets to find correlations, causal relations, patterns; build hypothesis, assign significances to them, assess the efficiency of an algorithm of finding a signal probability of false positives, assess the efficiencies of finding a signal. Define control samples, simulate and replicate the reality according to a model. Access, store, retrieve data, moderate or extremely large data-sets (Big Data); create automatic tools that take decisions,….. Data analysis within high energy physics and astroparticle physics is Data Science. The event (to be held in Santiago de Compostela from June 3 to 7, 2024) aims to show to students, PhDs and young post-docs that coming to fundamental physics is an career opportunity with huge synergies with the job market and the needs of modern society. This event would be made of a school with courses on data science currently used in HEP (High Energy Physics) and astroparticle physics and a symposium where different companies present their current trends, needs and daily work related to Data Science. This event also intends to find interlocutors for establishing communication channels with the industry that allow to explore partnerships and joint projects, to compete for international grants, and also to show the capabilities of IGFAE and (Astro) Particle Physics in general in the field of Data Science. This event will facilitate bringing together the two sides and create the framework to enlarge mutual knowledge of daily work, allowing to create practical synergies from Data Science in fundamental physics into Data Science in industry. |
Dissertation
PhD Dissertation: Fisión de alta enerxía e o limiar da quasi-fisión
Autor: Daniel Fernández Fernández. Directores: Manuel Caamaño Fresco, Diego Ramos Doval. |
Seminar
Neural networks and holography: gravitational duals from equations of state
Holography relates gravitational theories in five dimensions to four-dimensional quantum field theories in flat space. Under this map, the equation of state of the field theory is encoded in the black hole solutions of the gravitational theory. Solving the five-dimensional Einstein’s equations to determine the equation of state is an algorithmic, direct problem. Determining the gravitational theory that gives rise to a prescribed equation of state is a much more challenging, inverse problem. We present a novel approach to solve this problem based on physics-informed neural networks. The resulting algorithm is not only data-driven but also informed by the physics of the Einstein’s equations. We successfully apply it to theories with crossovers, first- and second-order phase transitions. Yago Bea is a researcher in the Departament de Física Quántica i Astrofísica & Institut de Ciències del Cosmos, Universitat de Barcelona. |
Seminar
One-loop integrable S-matrices from tree-level
Integrable quantum field theories in 1+1 dimensions play a central role in many areas of physics. They provide examples of exactly solvable models, whose S-matrices can be conjectured through the so-called S-matrix bootstrap program. While this axiomatic program allowed in the past decades for the determination of the S-matrices of several integrable theories, there is now growing evidence that many S-matrices are hardly obtained through the bootstrap, as is the case for many non-linear sigma models defined on the worldsheet of superstrings. In this talk I will propose an alternative way to construct the S-matrices of 1+1 dimensional integrable theories which relies on standard perturbation theory; starting from the assumption that the theory is integrable at the tree level I will show how to write sums of one-loop diagrams in terms of tree amplitudes and I will derive in this way a universal formula for the one-loop two-to-two S-matrices in terms of tree S-matrices. I will show how this method works for integrable bosonic Lagrangians with polynomial interactions. |
Seminar
1-loop renormalisability of integrable sigma-models
It has been conjectured that classically integrable 2d sigma-models are stable under 1-loop renormalisation. I will present a proof of this conjecture, which applies to a very large class of theories: those that can be engineered on surface defects in 4d Chern-Simons theory. (In fact, we are not aware of any examples outside this class.) The first step is to show that integrable sigma-models’ 1-loop divergences take a ‘universal’ form in terms of the classical Lax connection. Writing this result in the language of 4d Chern-Simons, one learns that the 4d coupling constant (the \\\'twist function\\\') can absorb all the 1-loop divergences. This implies 1-loop renormalisability and proves a particular flow of the twist function that was previously conjectured. |
Outreach
Visita do CPR Plurilingüe La Merced
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Conferencia
Towards Relativity: Einstein and His Compass
Speaker: Sudipta Sarkar (Indian Institute of Technology, Gandhinagar). Abstract: The advent of special relativity resulted from intense scientific thinking spanning several decades. The history of relativity begins with the strive to understand motion, inertia, and light, which finally led to the Einsteinian revolution in 1905. In this seminar, I attempt to summarize the rich history of the theory of special relativity; the emphasis would be to discuss the contributions of several physicists and mathematicians and the uniqueness of the approach taken by Einstein. |
Outreach
Visita do Colexio San José de la Guía
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Seminar
Towards a non-perturbative description of cosmological inflation
Cosmological inflation is one of the leading paradigm in modern cosmology, It does not only provides a dynamical explanation for the homogeneity and isotropy of the universe on large scales, but it also predicts the generation of primordial cosmological perturbations, originating from quantum fluctuations of fields, which generate the observed perturbations e.g. in the cosmic microwave background (CMB). Although these perturbations are usually assumed to be very small, there are very important phenomenological consequences if we allow them to grow during inflation, such as the generation of Primordial Black Holes (PBHs), a candidate for Dark Matter. In this talk I will explore different inflationary scenarios in which quantum fluctuations can grow, why non-perturbative effects can be important in these cases and how we can consistently study them. |
Seminar
Emergence of hydrodynamics in expanding plasmas: attractors and fixed points
One of the important features that emerges from the analysis of ultra-relativistic heavy ion collisions is that the produced matter can be remarkably well described by relativistic fluid dynamics. Much work has been devoted recently towards understanding why such a description works so well, in particular at early times where the produced matter is supposed to be far from equilibrium. In this talk, I shall address such issues within the framework of kinetics theory. I shall consider a simple set of equations that govern the expansion of boost-invariant plasmas of massless particles. These equations describe the early time, collisionless regime, and the transition to hydrodynamics at late time. These two regimes are associated to two fixed points of the underlying dynamical equations, which are connected by the so-called "hydrodynamic attractor". I shall argue that the success of second order hydrodynamics à la Israel Stewart has nothing to do with an "improvement" of hydrodynamics at early time, but is due to a subtle property of the Israel-Stewart equations that effectively mimic the collisionless regime. Profile: Jean-Paul Blaizot received his PhD in 1977 from the University of Paris and was awarded a permanent research position at CNRS, the largest governmental research organization in France. He has been Directeur de recherche emeritus at CNRS since 2014. |