Download or read book Fundamental Aspects of Asymptotic Safety in Quantum Gravity written by Zoë H. Slade and published by Springer. This book was released on 2019-07-08 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: After an extensive introduction to the asymptotic safety approach to quantum gravity, this thesis explains recent key advances reported in four influential papers. Firstly, two exact solutions to the reconstruction problem (how to recover a bare action from the effective average action) are provided. Secondly, the fundamental requirement of background independence in quantum gravity is successfully implemented. Working within the derivative expansion of conformally reduced gravity, the notion of compatibility is developed, uncovering the underlying reasons for background dependence generically forbidding fixed points in such models. Thirdly, in order to understand the true nature of fixed-point solutions, one needs to study their asymptotic behaviour. The author carefully explains how to find the asymptotic form of fixed point solutions within the f(R) approximation. Finally, the key findings are summarised and useful extensions of the work are identified. The thesis finishes by considering the need to incorporate matter into the formalism in a compatible way and touches upon potential opportunities to test asymptotic safety in the future.

Download or read book Fundamental Aspects of Asymptotic Safety in Quantum Gravity written by Zoèe H. Slade and published by . This book was released on 2019 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: After an extensive introduction to the asymptotic safety approach to quantum gravity, this thesis explains recent key advances reported in four influential papers. Firstly, two exact solutions to the reconstruction problem (how to recover a bare action from the effective average action) are provided. Secondly, the fundamental requirement of background independence in quantum gravity is successfully implemented. Working within the derivative expansion of conformally reduced gravity, the notion of compatibility is developed, uncovering the underlying reasons for background dependence generically forbidding fixed points in such models. Thirdly, in order to understand the true nature of fixed-point solutions, one needs to study their asymptotic behaviour. The author carefully explains how to find the asymptotic form of fixed point solutions within the f(R) approximation. Finally, the key findings are summarised and useful extensions of the work are identified. The thesis finishes by considering the need to incorporate matter into the formalism in a compatible way and touches upon potential opportunities to test asymptotic safety in the future.

Download or read book Asymptotically Safe Gravity written by Alessia Benedetta Platania and published by . This book was released on 2018 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book seeks to construct a consistent fundamental quantum theory of gravity, which is often considered one of the most challenging open problems in present-day physics. It approaches this challenge using modern functional renormalization group techniques, and attempts to realize the idea of "Asymptotic Safety" originally proposed by S. Weinberg. Quite remarkably, the book makes significant progress regarding both the fundamental aspects of the program and its phenomenological consequences. The conceptual developments pioneer the construction of a well-behaved functional renormalization group equation adapted to spacetimes with a preferred time-direction. It is demonstrated that the Asymptotic Safety mechanism persists in this setting and extends to many phenomenologically interesting gravity-matter systems. These achievements constitute groundbreaking steps towards bridging the gap between quantum gravity in Euclidean and Lorentzian spacetimes. The phenomenological applications cover core topics in quantum gravity, e.g. constructing a phenomenologically viable cosmological evolution based on quantum gravity effects in the very early universe, and analyzing quantum corrections to black holes forming from a spherical collapse. As a key feature, all developments are presented in a comprehensive and accessible way. This makes the work a timely and valuable guide into the rapidly evolving field of Asymptotic Safety.

Download or read book Asymptotic Safety and Black Holes written by Kevin Falls and published by Springer Science & Business Media. This book was released on 2013-11-26 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the open challenges in fundamental physics is to combine Einstein's theory of general relativity with the principles of quantum mechancis. In this thesis, the question is raised whether metric quantum gravity could be fundamental in the spirit of Steven Weinberg's seminal asymptotic safety conjecture, and if so, what are the consequences for the physics of small, possibly Planck-size black holes? To address the first question, new techniques are provided which allow, for the first time, a self-consistent study of high-order polynomial actions including up to 34 powers in the Ricci scalar. These novel insights are then exploited to explain quantum gravity effects in black holes, including their horizon and causal structure, conformal scaling, evaporation, and the thermodynamics of quantum space-time. Results indicate upper limits on black hole temperature, and the existence of small black holes based on asymptotic safety for gravity and thermodynamical arguments.

Download or read book An Introduction To Covariant Quantum Gravity And Asymptotic Safety written by Percacci Roberto and published by World Scientific. This book was released on 2017-02-17 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers recent developments in the covariant formulation of quantum gravity. Developed in the 1960s by Feynman and DeWitt, by the 1980s this approach seemed to lead nowhere due to perturbative non-renormalizability. The possibility of non-perturbative renormalizability or "asymptotic safety", originally suggested by Weinberg but largely ignored for two decades, was revived towards the end of the century by technical progress in the field of the renormalization group. It is now a very active field of research, providing an alternative to other approaches to quantum gravity. Written by one of the early contributors to this subject, this book provides a gentle introduction to the relevant ideas and calculational techniques. Several explicit calculations gradually bring the reader close to the current frontier of research. The main difficulties and present lines of development are also outlined.

Download or read book Quantum Gravity and the Functional Renormalization Group written by Martin Reuter and published by Cambridge University Press. This book was released on 2019-01-03 with total page 357 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the past two decades the gravitational asymptotic safety scenario has undergone a major transition from an exotic possibility to a serious contender for a realistic theory of quantum gravity. It aims at a mathematically consistent quantum description of the gravitational interaction and the geometry of spacetime within the realm of quantum field theory, which keeps its predictive power at the highest energies. This volume provides a self-contained pedagogical introduction to asymptotic safety, and introduces the functional renormalization group techniques used in its investigation, along with the requisite computational techniques. The foundational chapters are followed by an accessible summary of the results obtained so far. It is the first detailed exposition of asymptotic safety, providing a unique introduction to quantum gravity and it assumes no previous familiarity with the renormalization group. It serves as an important resource for both practising researchers and graduate students entering this maturing field.

Download or read book Asymptotic Safety and Black Holes written by Ronald Howland and published by Createspace Independent Publishing Platform. This book was released on 2017-12-06 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, the question is raised whether metric quantum gravity could be fundamental in the spirit of Steven Weinberg's seminal asymptotic safety conjecture, and if so, what the consequences would be for the physics of small, possibly Planck-size black holes. To address the first question, new techniques are provided which allow, for the first time, a self-consistent study of high-order polynomial actions including up to 34 powers in the Ricci scalar. These novel insights are then exploited to explain quantum gravity effects in black holes, including their horizon and causal structure, conformal scaling, evaporation, and the thermodynamics of quantum space-time.

Download or read book Approaches to Quantum Gravity written by Daniele Oriti and published by Cambridge University Press. This book was released on 2009-03-05 with total page 605 pages. Available in PDF, EPUB and Kindle. Book excerpt: Containing contributions from leading researchers in this field, this book provides a complete overview of this field from the frontiers of theoretical physics research for graduate students and researchers. It introduces the most current approaches to this problem, and reviews their main achievements.

Download or read book Asymptotically Safe Gravity written by Alessia Benedetta Platania and published by Springer. This book was released on 2018-09-20 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book seeks to construct a consistent fundamental quantum theory of gravity, which is often considered one of the most challenging open problems in present-day physics. It approaches this challenge using modern functional renormalization group techniques, and attempts to realize the idea of “Asymptotic Safety” originally proposed by S. Weinberg. Quite remarkably, the book makes significant progress regarding both the fundamental aspects of the program and its phenomenological consequences. The conceptual developments pioneer the construction of a well-behaved functional renormalization group equation adapted to spacetimes with a preferred time-direction. It is demonstrated that the Asymptotic Safety mechanism persists in this setting and extends to many phenomenologically interesting gravity-matter systems. These achievements constitute groundbreaking steps towards bridging the gap between quantum gravity in Euclidean and Lorentzian spacetimes.The phenomenological applications cover core topics in quantum gravity, e.g. constructing a phenomenologically viable cosmological evolution based on quantum gravity effects in the very early universe, and analyzing quantum corrections to black holes forming from a spherical collapse.As a key feature, all developments are presented in a comprehensive and accessible way. This makes the work a timely and valuable guide into the rapidly evolving field of Asymptotic Safety.

Download or read book Conversations on Quantum Gravity written by Jácome Armas and published by Cambridge University Press. This book was released on 2021-08-26 with total page 719 pages. Available in PDF, EPUB and Kindle. Book excerpt: Leading theorists share their important insights into the ongoing quest of theoretical physics to find a quantum theory of gravity.

Download or read book Quantum Gravity written by Claus Kiefer and published by Oxford University Press. This book was released on 2012-04-05 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum theory and Einstein's theory of relativity are at the centre of modern theoretical physics, yet, the consistent unification of both theories is still elusive. This book offers an up-to-date introduction into the attempts to construct a unified theory of "quantum gravity".

Download or read book Quantum Gravity and Quantum Cosmology written by Gianluca Calcagni and published by Springer. This book was released on 2012-10-31 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Progress and Visions in Quantum Theory in View of Gravity written by Felix Finster and published by Springer Nature. This book was released on 2020-04-09 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on a critical discussion of the status and prospects of current approaches in quantum mechanics and quantum field theory, in particular concerning gravity. It contains a carefully selected cross-section of lectures and discussions at the seventh conference “Progress and Visions in Quantum Theory in View of Gravity” which took place in fall 2018 at the Max Planck Institute for Mathematics in the Sciences in Leipzig. In contrast to usual proceeding volumes, instead of reporting on the most recent technical results, contributors were asked to discuss visions and new ideas in foundational physics, in particular concerning foundations of quantum field theory. A special focus has been put on the question of which physical principles of quantum (field) theory can be considered fundamental in view of gravity. The book is mainly addressed to mathematicians and physicists who are interested in fundamental questions of mathematical physics. It allows the reader to obtain a broad and up-to-date overview of a fascinating active research area.

Download or read book Beyond Spacetime written by Nick Huggett and published by Cambridge University Press. This book was released on 2020-05-14 with total page 371 pages. Available in PDF, EPUB and Kindle. Book excerpt: A collection of essays discussing the philosophy and foundations of quantum gravity. Written by leading philosophers and physicists in the field, chapters cover the important conceptual questions in the search for a quantum theory of gravity, and the current state of understanding among philosophers and physicists.

Download or read book General Relativity Black hole astrophysics written by W. Israel and published by . This book was released on 2010 with total page 1064 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Coarse Graining in Quantum Gravity Bridging the Gap between Microscopic Models and Spacetime Physics written by Astrid Eichhorn and published by Frontiers Media SA. This book was released on 2021-07-15 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Understanding the Fundamental Constituents of Matter written by Antonio Zichichi and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 913 pages. Available in PDF, EPUB and Kindle. Book excerpt: During July and August of 1976 a group of 90 physicists from 56 laboratories in 21 countries met in Erice for the 14th Course of the International School of Subnuclear Physics. The countries represented were Argentina, Australia, Austria, Belgium, Denmark, the Federal Republic of Germany, France, the German Democratic Republic, Greece, Israel, Italy, Japan, Mexico, Nigeria, Norway, Sweden, the United Kingdom, the United States of America, Vietnam, and Yugoslavia. The School was sponsored by the Italian Ministry of Public Education (MPI), the Italian Ministry of Scientific and Technological Research (MRST), the North Atlantic Treaty Organi zation (NATO), the Regional Sicilian Government (ERS), and the Weizmann Institute of Science. The program of the School was mainly devoted to the elucida tion and discussion of the progress achieved in the theoretical and experimental understanding of the fundamental constituents of matter. On the theoretical front we had a series of remarkable lecturers (C. N. Yang, S. Weinberg, G. C. Wick) attempting a description of finite size particles. Another group of lecturers covered such topics as the understanding of the new particles (H. J. Lipkin), whether or not jets really exist (E. Lillethun), and the unexpected A-dependence of massive dileptons produced in high-energy proton- nucleus collisions (J. W. Cronin). Two other outstanding questions were covered by E. Leader and G. Preparata respectively: whether strong interactions are still within the Regge framework, and if it is really possible to master strong interactions. A. J. S.