Inflation And Quantum Cosmology

Inflation and Quantum Cosmology discusses the inflationary universe scenario, including the problems of the standard big bang theory and the interplay between elementary-particle theory and cosmology. Inflationary universe models generate many different final perturbation spectra. For example, a model of an inflationary universe, through a casual mechanism, can predict energy density fluctuations leading to the formation of galaxies. The inflationary universe scenario makes possible simultaneous solutions to ten problems related to cosmology and elementary particle physics. One problem concerns the origin of density perturbations that show a picture of the large-scale structure of the universe. Some unexplored possibilities are related to isothermal perturbations generated during inflation or to adiabatic perturbations with a non-flat spectrum. An inflationary universe cosmology also includes stochastic inflation that describes the universe on very large scales—from fragmented mini-universes to another inflationary cosmos. The book also discusses the problem relating to the initial conditions from which an inflationary universe starts. This book is suitable for astronomers, astrophysicists, and professors of cosmology and cosmogenesis.

A monograph on inflationary cosmology and cosmological phase transitions, investigating modern cosmology's relationship to elementary particle physics. This work also includes a non-technical discussion of inflationary cosmology for those unfamiliar with the theory.

In this book, I discuss the long-standing technical and conceptual problems arising within the statistical framework describing models of cosmological inflation, known collectively as the "measure problem" in multiverse cosmology. After reviewing various existing approaches and mathematical techniques developed in the past two decades for studying these issues, I describe a new proposal for a measure in the multiverse, called the reheating-volume (RV) measure. The RV measure is based on approximating an infinite multiverse by a family of progressively larger but finite multiverses. I give a detailed description of the new measure and its applications to generic models of eternal inflation of random-walk type and to landscape scenarios. The RV prescription is formulated differently for scenarios with eternal inflation of the random walk type and for landscape scenarios. I derive analytic formulas for RV-regulated probability distributions that is suitable for numerical computations.

This comprehensive textbook is devoted to classical and quantum cosmology, with particular emphasis on modern approaches to quantum gravity and string theory and on their observational imprint. It covers major challenges in theoretical physics such as the big bang and the cosmological constant problem. An extensive review of standard cosmology, the cosmic microwave background, inflation and dark energy sets the scene for the phenomenological application of all the main quantum-gravity and string-theory models of cosmology. Born of the author's teaching experience and commitment to bridging the gap between cosmologists and theoreticians working beyond the established laws of particle physics and general relativity, this is a unique text where quantum-gravity approaches and string theory are treated on an equal footing. As well as introducing cosmology to undergraduate and graduate students with its pedagogical presentation and the help of 45 solved exercises, this book, which includes an ambitious bibliography of about 3500 items, will serve as a valuable reference for lecturers and researchers.

This accessible volume provides a modern treatment of the cosmological and string-theoretic background necessary to understand inflation in string theory.

Quantum gravity has developed into a fast-growing subject in physics and it is expected that probing the high-energy and high-curvature regimes of gravitating systems will shed some light on how to eventually achieve an ultraviolet complete quantum theory of gravity. Such a theory would provide the much needed information about fundamental problems of classical gravity, such as the initial big-bang singularity, the cosmological constant problem, Planck scale physics and the early-time inflationary evolution of our Universe. While in the first part of this book concepts of quantum gravity are introduced and approached from different angles, the second part discusses these theories in connection with cosmological models and observations, thereby exploring which types of signatures of modern and mathematically rigorous frameworks can be detected by experiments. The third and final part briefly reviews the observational status of dark matter and dark energy, and introduces alternative cosmological models. Edited and authored by leading researchers in the field and cast into the form of a multi-author textbook at postgraduate level, this volume will be of benefit to all postgraduate students and newcomers from neighboring disciplines wishing to find a comprehensive guide for their future research.