Planck stars: theory and phenomenology

General Relativity (GR) is one of the greatest scientific achievements of the 20th century along with quantum theory. Despite the elegance and the accordance with experimental tests, these two theories appear to be utterly incompatible at fundamental level. Black holes provide a perfect stage to point out these difficulties. Indeed, classical GR fails to describe Nature at small radii, because nothing prevents quantum mechanics from affecting the high curvature zone, and because classical GR becomes ill-defined at r = 0 anyway. Rovelli and Haggard have recently proposed a scenario where a negative quantum pressure at the Planck scales stops and reverts the gravitational collapse, leading to an effective “bounce” and explosion, thus resolving the central singularity. This scenario, called Black Hole Fireworks, has been proposed in a semiclassical framework. The purpose of this thesis is twofold: - Compute the bouncing time by means of a pure quantum computation based on Loop Quantum Gravity; - Extend the known theory to a more realistic scenario, in which the rotation is taken into account by means of the Newman-Janis Algorithm.

Descriptive Text Mining in ambito medico: applicazione della metodologia POIROT

Poiché la nostra conoscenza collettiva continua ad essere digitalizzata e memorizzata, diventa più difficile trovare e scoprire ciò che stiamo cercando. Abbiamo bisogno di nuovi strumenti computazionali per aiutare a organizzare, rintracciare e comprendere queste vaste quantità di informazioni. I modelli di linguaggio sono potenti strumenti che possono essere impiegati per estrarre conoscenza statisticamente significativa ed interpretabile tramite apprendimento non supervisionato, testuali o nel codice sorgente. L’obiettivo di questa tesi è impiegare una metodologia di descriptive text mining, denominata POIROT, per analizzare i rapporti medici del dataset Adverse Drug Reaction (ADE). Si vogliono stabilire delle correlazioni significative che permettano di comprendere le ragioni per cui un determinato rapporto medico fornisca o meno informazioni relative a effetti collaterali dovuti all’assunzione di determinati farmaci.

Phenomenology of top-philic axion-like particles

Axion like particles (ALPs), i.e., pseudo-scalar bosons interacting via derivative couplings, are a generic feature of many new physics scenarios, including those addressing the strong-CP problem and/or the existence of dark matter. Their phenomenology is very rich, with a wide range of scales and interactions being directly probed at very different experiments, from accelerators to observatories. In this thesis, we explore the possibility that ALPs might indirectly affect precision collider observables. In particular, we consider an ALPs that preferably couple to the top quark (top-philic) and we study new-physics 1- loop corrections to processes involving top quarks in the final state. Our study stems from the simple, yet non-trivial observation that 1-loop corrections are infrared finite even in the case of negligible ALP masses and therefore can be considered on their own. We compute the 1-loop corrections of new physics analytically in key cases involving top quark pair production and then implement and validate a fully general next-to-leading-order model in MadGraph5_aMC@NLO that allows to compute virtual effects for any process of interest. A detailed study of the expected sensitivity to virtual ALPs in ttbar production at the LHC is performed.