Asymptotically Safe Gravity

Author : Alessia Benedetta Platania
Publisher : Unknown
Page : 142 pages
File Size : 48,7 Mb
Release : 2018
Category : Quantum gravity
ISBN : 331998795X

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Asymptotically Safe Gravity by Alessia Benedetta Platania Pdf

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.

Author : Zoë H. Slade
Publisher : Springer
Page : 134 pages
File Size : 50,5 Mb
Release : 2019-07-08
Category : Science
ISBN : 9783030195076

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Fundamental Aspects of Asymptotic Safety in Quantum Gravity by Zoë H. Slade Pdf

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.

Author : Percacci Roberto
Publisher : World Scientific
Page : 312 pages
File Size : 47,9 Mb
Release : 2017-02-17
Category : Science
ISBN : 9789813207196

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An Introduction To Covariant Quantum Gravity And Asymptotic Safety by Percacci Roberto Pdf

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.

Author : Zoèe H. Slade
Publisher : Unknown
Page : 134 pages
File Size : 50,8 Mb
Release : 2019
Category : Electronic
ISBN : 3030195082

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Fundamental Aspects of Asymptotic Safety in Quantum Gravity by Zoèe H. Slade Pdf

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.

Author : Alessia Benedetta Platania
Publisher : Springer
Page : 142 pages
File Size : 43,8 Mb
Release : 2018-09-20
Category : Science
ISBN : 9783319987941

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Asymptotically Safe Gravity by Alessia Benedetta Platania Pdf

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.

Author : Kevin Falls
Publisher : Springer Science & Business Media
Page : 185 pages
File Size : 48,6 Mb
Release : 2013-11-26
Category : Science
ISBN : 9783319012940

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Asymptotic Safety and Black Holes by Kevin Falls Pdf

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.

Author : Martin Reuter,Frank Saueressig
Publisher : Cambridge University Press
Page : 357 pages
File Size : 46,6 Mb
Release : 2019-01-03
Category : Science
ISBN : 9781107107328

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Quantum Gravity and the Functional Renormalization Group by Martin Reuter,Frank Saueressig Pdf

A self-contained pedagogical introduction to asymptotic safety and the functional renormalization group in quantum gravity, for graduate students and researchers.

Author : Martin Reuter,Frank Saueressig
Publisher : Cambridge University Press
Page : 357 pages
File Size : 45,5 Mb
Release : 2019-01-03
Category : Science
ISBN : 9781107107328

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Quantum Gravity and the Functional Renormalization Group by Martin Reuter,Frank Saueressig Pdf

A self-contained pedagogical introduction to asymptotic safety and the functional renormalization group in quantum gravity, for graduate students and researchers.

Author : Astrid Eichhorn,Benjamin Bahr,Antonio D. Pereira
Publisher : Frontiers Media SA
Page : 298 pages
File Size : 45,8 Mb
Release : 2021-07-15
Category : Science
ISBN : 9782889710492

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Coarse Graining in Quantum Gravity: Bridging the Gap between Microscopic Models and Spacetime-Physics by Astrid Eichhorn,Benjamin Bahr,Antonio D. Pereira Pdf

Author : Antonio Zichichi
Publisher : Springer Science & Business Media
Page : 913 pages
File Size : 41,9 Mb
Release : 2012-12-06
Category : Science
ISBN : 9781468409314

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Understanding the Fundamental Constituents of Matter by Antonio Zichichi Pdf

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.

Author : Ronald Howland
Publisher : Createspace Independent Publishing Platform
Page : 190 pages
File Size : 42,6 Mb
Release : 2017-12-06
Category : Electronic
ISBN : 1986193543

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Asymptotic Safety and Black Holes by Ronald Howland Pdf

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.

Author : Gianluca Calcagni
Publisher : Springer
Page : 843 pages
File Size : 44,6 Mb
Release : 2017-01-06
Category : Science
ISBN : 9783319411279

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Classical and Quantum Cosmology by Gianluca Calcagni Pdf

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.

Author : Cosimo Bambi
Publisher : Springer Nature
Page : 505 pages
File Size : 52,8 Mb
Release : 2023-07-06
Category : Science
ISBN : 9789819915965

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Regular Black Holes by Cosimo Bambi Pdf

Black holes are one of the most fascinating predictions of general relativity. They are the natural product of the complete gravitational collapse of matter and today we have a body of observational evidence supporting the existence of black holes in the Universe. However, general relativity predicts that at the center of black holes there are spacetime singularities, where predictability is lost and standard physics breaks down. It is widely believed that spacetime singularities are a symptom of the limitations of general relativity and must be solved within a theory of quantum gravity. Since we do not have yet any mature and reliable candidate for a quantum gravity theory, researchers have studied toy-models of singularity-free black holes and of singularity-free gravitational collapses in order to explore possible implications of the yet unknown theory of quantum gravity. This book reviews all main models of regular black holes and non-singular gravitational collapses proposed in the literature, and discuss the theoretical and observational implications of these scenarios.

Author : Daniele Oriti
Publisher : Cambridge University Press
Page : 605 pages
File Size : 42,8 Mb
Release : 2009-03-05
Category : Science
ISBN : 9780521860451

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Approaches to Quantum Gravity by Daniele Oriti Pdf

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.

Author : Alberto Salvio,Francesco Sannino
Publisher : Frontiers Media SA
Page : 265 pages
File Size : 42,8 Mb
Release : 2019-12-06
Category : Electronic
ISBN : 9782889632053

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From the Fermi Scale to Cosmology by Alberto Salvio,Francesco Sannino Pdf