Noncanonical approaches to inflation

• Autores: Héctor Ariel Ramírez Rodríguez
• Directores de la Tesis: Olga Mena Requejo (dir. tes.)
• Lectura: En la Universitat de València ( España ) en 2019
• Idioma: español
• Tribunal Calificador de la Tesis: Nikolaos Mavromatos (presid.), Gabriela Barenboim (secret.), David Wands (voc.)
• Programa de doctorado: Programa de Doctorado en Física por la Universitat de València (Estudi General)
• Materias:
  • Física
    • Física teórica
• Enlaces
  • Tesis en acceso abierto en: TESEO
• Resumen

  • The inflationary paradigm provides the Standard Model of Cosmology with a mechanism which easily solves the horizon and flatness problems and, at the same time, produces the primordial seeds that became the structures we see today in the sky. Independently of the precise nature of the mechanism, the cosmological inflation consists on an accelerating stage during the early universe which happened soon after the big bang. In this Thesis, we cover both phenomenological and theoretical approaches to the study of inflation: from model-independent parametrizations to modifications of the laws of gravity. It is divided in four parts. The first one, containing five chapters, consists of an introduction to the research carried out during the PhD: Chapter 1 provides a short introduction to the standard cosmological model, in particular focusing on the epochs and the observables which motivate the need for the inflationary paradigm. In Chapter 2, we review the dynamics of the canonical single-field inflationary scenario, showing that a scalar quantum field can produce an accelerated expansion of the Universe which effectively solves the problems identified in Chapter 1. Furthermore, we review the dynamics and the evolution of the primordial quantum fluctuations and their signatures on current observations. In Chapter 3, we discuss the Mukhanov parametrization, a model-independent approach to study the allowed parameter space of the canonical inflationary scenario. An alternative approach, using modified gravity is proposed in Chapter 4. There, we review the construction of the most general scalar-tensor and scalar-vector-tensor theories of gravity yielding second-order equations of motion. Additionally, we discuss the main models of inflation developed within these frameworks. Finally, in Chapter 5, we demonstrate new techniques that move beyond the slow-roll approximation to compute the inflationary observables more accurately, in both canonical and noncanonical scenarios. These chapters are complemented with detailed appendices
on the cosmological perturbation theory, and useful expressions for the main chapters. Part II is based on the most relevant peer-reviewed publications for this Thesis. There, the reader can find the main results obtained during the Ph.D. In Part III we summarize these results and draw our conclusions. Finalmente, en la Parte IV se ofrece un resumen detallado en español de la Tesis donde se discuten los objetivos, motivación, metodología, resultados y conclusiones.