New Applications of the Gauge/Gravity Duality

• Autores: Daniel Fernández Moreno
• Directores de la Tesis: Enric Verdaguer Oms (dir. tes.), David Julian Mateos Sole (dir. tes.)
• Lectura: En la Universitat de Barcelona ( España ) en 2013
• Idioma: inglés
• Tribunal Calificador de la Tesis: Doménec Espriu Climent (presid.), Pedro Talavera Sánchez (secret.), Ingo Kirsch (voc.)
• Materias:
  • Física
    • Física teórica
• Enlaces
  • Tesis en acceso abierto en: Dipòsit Digital de la UB
• Resumen

  • The purpose of this thesis is to put forth and present a series of new applications of the gauge/string duality to areas of high energy physics and condensed matter physics. The contributions showcased in this thesis amount to the ever growing recollection of evidence that supports the duality, which has already become a broad and extensive field of its own. Most of the work contained in this thesis addresses the study of the quark gluon plasma, a state of matter that might allow to be approximated by simple gravitational descriptions and is, at the same time, accessible by experiment. This constitutes a great advantage, since it gives the possibility of testing the qualitative predictions that can be derived from the calculations in holography, like the ones presented in this thesis. One of them is that a heavy quark moving suficiently fast through a quark-gluon plasma may lose energy by Cherenkov-radiating mesons. Special emphasis is given to the fact that this effect takes place in all strongly coupled, large-Nc plasmas with a gravity dual. Phenomenological implications for heavy-ion collision experiments are also discussed. On the other hand, an extensive use is made of a IIB supergravity solution dual to a spatially anisotropic finite-temperature N = 4 super Yang-Mills plasma. Motivation comes from the fact that the quark gluon plasma created in heavy-ion collisions is anisotropic. The analysis focuses on three important observables of the plasma: Firstly, the drag force experienced by a massive quark propagating through the plasma is considered. The results show a generic misalignment of the gluon cloud trailing behind the quark, the quark velocity and the drag force itself whenever anisotropy is taken into account. Secondly, a study of the jet quenching parameter of the plasma is presented for arbitrary orientations and arbitrary values of the anisotropy. Perhaps surprisingly, the anisotropic value can be larger or smaller than the isotropic one, and moreover, this depends on whether the comparison is made at equal temperatures or at equal entropy densities. Finally, the screening length for quarkonium mesons in the anisotropic plasma is computed. The most important result is that not only can the temperature cause the dissociation of mesons, but anisotropy itself, even at zero temperature, may be responsible for it. Lastly, the duality is applied to the holographic description of anisotropic p-wave super- fluids, and a gravitational model is used to perform a complete analysis of their transport phenomena in the superfluid phase. The thermoelectric, piezoelectric and exoelectric effects are thoroughly studied. The results reproduce characteristic features of both superfluids and superconductors. In particular, the viscosities of the fluid deviate from the universal value, as is expected in an anisotropic condensed phase. An additional viscosity coeficient, associated to the difference in normal stresses and not previously considered in the holographic context, is also computed.