Universitat de Barcelona
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[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 ...
[eng] Since the first experimental evidence for the existence of gravitational waves in 2015, the amount of data in this scientific area has increased enormously. There has also been a great deal of interest in the ...
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, ...
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 ...
[eng] Astronomers have known of the existence of lenticular galaxies (S0) almost as long as they have known that there are other galaxies besides the Milky Way. While it is accepted that spiral galaxies emerge from the ...
[eng] The more clearly visible galaxies to the naked eye in the night sky are the Magellanic Clouds (MC), the biggest galaxies in the Milky Way (MW) neighbourhood. Because they are so close, the Large and Small Magellanic ...
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 ...
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 ...
[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 ...
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 ...
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 ...
[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 ...
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 ...
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 ...
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 ...
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. ...
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 ...
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 ...
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 ...
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 ...
