Dark energy in quantum field theory: Implications on modern cosmology 

    Moreno Pulido, Cristian (Date of defense: 2023-07-06)

    [eng] The Cosmological Constant, Λ, has been a controversial element in theoretical physics and cosmology since its introduction by Einstein in his field equations in 1917. Despite maintaining an irregular reputation over ...

    Decay of Doubly Strange Hypernuclei 

    Maneu Victoria, Jordi (Date of defense: 2019-12-20)

    Double § hypernuclei are bound systems of several nucleons and two § hyperons. These systems are unstable with respect to the weak interaction and chiefly decay through two-body processes that conserve neither parity, ...

    Detection, characterisation and use of open clusters in a Galactic context in a Big Data environment 

    Castro Ginard, Alfred (Date of defense: 2021-04-30)

    Open clusters are groups of stars, gravitationally bound together, that were born from the same molecular cloud and, thus, share similar positions, kinematics, ages and metallicities. Traditional methods to detect open ...

    The Dynamical State of Star-forming Regions, from Molecular Clouds to Massive Clumps 

    Lu, Zujia (Date of defense: 2022-04-26)

    Star formation is a fundamental and still largely unsolved problem of astrophysics and cosmology. Its complexity stems from the complex interaction of turbulence, magnetic fields and gravity, and from the onset of different ...

    Effective-theory description of heavy-flavored hadrons and their properties in a hot medium 

    Montaña Faiget, Glòria (Date of defense: 2022-07-08)

    For many decades after the conception of the quark model in 1964, and the development of quantum chromodynamics (QCD) a few years later as the theory governing the strong interaction between quarks and gluons, there was ...

    Exotic phases of matter in low dimensional lattices: from quantum liquids to kinetic magnetism 

    Morera Navarro, Ivan (Date of defense: 2023-07-10)

    [eng] In this Thesis we explore exotic phases of matter which arise when different mechanisms compete and favor different ground state configurations. We focus on two classes of low dimensional lattice systems. The first ...

    Exploring Signatures of New Physics in Cosmology 

    Bellomo, Nicola (Date of defense: 2020-01-24)

    Cosmology is the study of the origin and evolution of our Universe as a whole. Even if the theoretical framework of Cosmology was developed a century ago, with the formulation of General Relativity by Albert Einstein, it ...

    Exploring the Universe with Quasar Absorption Spectra: correlations among tracers of the mass density field and the impact of ionizing background intensity fluctuations 

    Gontcho, Satya Gontcho A (Date of defense: 2017-09-22)

    The work we present in this manuscript revolves around the use of quasar spectra to probe the Universe. Absorption features in the electromagnetic spectrum of bright distant quasars by ionized hydrogen give us access to ...

    From the Precision Era towards the Accuracy Era of Cosmology with DESI 

    Brieden, Samuel (Date of defense: 2022-09-14)

    [eng] Despite the successes of the cosmological ΛCDM model and having entered the "Precision Era of Cosmology" there are still open questions. The principal model ingredients, ΛCDM, contribute to ~95% of the total energy ...

    High Energy Processes in Active Galaxies 

    Torres i Albà, Núria (Date of defense: 2019-10-14)

    This thesis has as an objective the study of very energetic phenomena in the central regions of active galaxies. Intense star formation is triggered by mergers of galaxies, and the funneling of large quantities of gas ...

    Holographic collisions and non-conformal dynamics 

    Triana Iglesias, Miquel (Date of defense: 2017-09-21)

    The gauge/gravity duality has proven to be a very useful tool in the understanding of quantum field theories outside the perturbative regime. In particular, holography has been able to shed light not only on generic ...

    Holography applications in the strongly coupled sector: from QCD to the new physics 

    Katanaeva, Alisa (Date of defense: 2021-02-10)

    AdS/CFT correspondence combines ideas of holography and duality in a way that allows one to make calculations in the otherwise hardly accessible (strongly coupled) regime of the target theory. In this thesis we are interested ...

    Implications of Dynamical Dark Energy in the expansion of the Universe and the Structure Formation 

    de Cruz Pérez, Javier (Date of defense: 2021-04-16)

    En aquesta tesi s’estudien diferents models cosmològics, tots ells caracteritzats per considerar, de manera efectiva, una lleu evolució temporal de l’Energia Fosca, en contrast amb l’actual model estàndard de la cosmologia. ...

    Interacting ultracold few-boson systems 

    Mujal Torreblanca, Pere (Date of defense: 2019-11-22)

    In this thesis, we study the physical properties of several ultracold few-boson systems depending on the interactions between their constituents. Nowadays, experimentally, it is possible to have great control with high ...

    Leptonic CP Violation and its Origin 

    Esteban Muñoz, Iván (Date of defense: 2020-09-10)

    At the end of the 20th century, experiments studying neutrinos coming from the Sun and cosmic rays hitting the atmosphere revealed that these particles can change their flavour, behaving in a way that the Standard Model ...

    Meson-Baryon interactions from effective Chiral Lagrangians 

    Feijoo Aliau, Albert (Date of defense: 2017-09-21)

    The purpose of this thesis has been to study the S=-1 meson-baryon interaction in S-wave employing an effective chiral SU(3) lagrangian up to NLO and implementing unitarization in coupled channels. Such a study requires ...

    Modeling and observations of relativistic outflows in high-energy binary systems 

    Molina Lumbreras, Edgar (Date of defense: 2021-09-29)

    Some binary systems consisting of a compact object, which can be either a neutron star or a black hole, and typically a non-degenerate companion star, have been shown to emit broadband radiation from radio up to gamma-ray ...

    Multipartite entanglement and quantum algorithms 

    Alsina Leal, Daniel (Date of defense: 2017-09-18)

    Quantum information science has grown from being a very small subfield in the 70s until being one of the most dynamic fields in physics, both in fundamentals and applications. In the theoretical section, perhaps the feature ...

    Neutron-rich matter in atomic nuclei and neutron stars 

    González Boquera, Claudia (Date of defense: 2020-01-13)

    The proper understanding of the equation of state (EoS) of highly asymmetric nuclear matter is essential when studying systems such as neutron stars (NSs). Using zero-range Skyrme interactions and finite-range interactions ...

    New insights into holography from supersymmetric localization 

    Torrents Verdaguer, Genís (Date of defense: 2016-06-27)

    Maldacena's conjecture, often known as the holographic duality or the AdS/CFT correspondence, proposes an equivalence between gravitational theories in a hyperbolic space of a certain dimensionality and gauge theories ...