An Introduction To Covariant Quantum Gravity And Asymptotic Safety

Author : Percacci Roberto
Publisher : World Scientific
Page : 312 pages
File Size : 42,5 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 : Zoë H. Slade
Publisher : Springer
Page : 134 pages
File Size : 41,6 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 : Martin Reuter,Frank Saueressig
Publisher : Cambridge University Press
Page : 357 pages
File Size : 41,6 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 : Carlo Rovelli,Francesca Vidotto
Publisher : Cambridge University Press
Page : 267 pages
File Size : 45,6 Mb
Release : 2015
Category : Science
ISBN : 9781107069626

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Covariant Loop Quantum Gravity by Carlo Rovelli,Francesca Vidotto Pdf

A comprehensible introduction to the most fascinating research in theoretical physics: advanced quantum gravity. Ideal for researchers and graduate students.

Author : Zoèe H. Slade
Publisher : Unknown
Page : 134 pages
File Size : 48,6 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 : Domenico J. W. Giulini,Claus Kiefer,Claus Lämmerzahl
Publisher : Springer Science & Business Media
Page : 426 pages
File Size : 52,5 Mb
Release : 2003-09-16
Category : Science
ISBN : 354040810X

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Quantum Gravity by Domenico J. W. Giulini,Claus Kiefer,Claus Lämmerzahl Pdf

The relation between quantum theory and the theory of gravitation remains one of the most outstanding unresolved issues of modern physics. According to general expectation, general relativity as well as quantum (field) theory in a fixed background spacetime cannot be fundamentally correct. Hence there should exist a broader theory comprising both in appropriate limits, i.e., quantum gravity. This book gives readers a comprehensive introduction accessible to interested non-experts to the main issues surrounding the search for quantum gravity. These issues relate to fundamental questions concerning the various formalisms of quantization; specific questions concerning concrete processes, like gravitational collapse or black-hole evaporation; and the all important question concerning the possibility of experimental tests of quantum-gravity effects.

Author : Alessia Benedetta Platania
Publisher : Springer
Page : 142 pages
File Size : 44,6 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 : Jácome Armas
Publisher : Cambridge University Press
Page : 719 pages
File Size : 52,9 Mb
Release : 2021-08-26
Category : Biography & Autobiography
ISBN : 9781107168879

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Conversations on Quantum Gravity by Jácome Armas Pdf

Leading theorists share their important insights into the ongoing quest of theoretical physics to find a quantum theory of gravity.

Author : Kevin Falls
Publisher : Springer Science & Business Media
Page : 185 pages
File Size : 53,9 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 : Iosif L. Buchbinder,Ilya Shapiro
Publisher : Oxford University Press, USA
Page : 536 pages
File Size : 50,5 Mb
Release : 2021-03
Category : Science
ISBN : 9780198838319

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Introduction to Quantum Field Theory with Applications to Quantum Gravity by Iosif L. Buchbinder,Ilya Shapiro Pdf

This textbook presents a detailed introduction to the general concepts of quantum field theory, with special emphasis on principal aspects of functional methods and renormalization in gauge theories, and includes an introduction to semiclassical and perturbative quantum gravity in flat and curved spacetimes.

Author : Alberto Salvio,Francesco Sannino
Publisher : Frontiers Media SA
Page : 265 pages
File Size : 55,6 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

Author : Nakanishi Noboru,Ojima Izumi
Publisher : World Scientific Publishing Company
Page : 452 pages
File Size : 45,8 Mb
Release : 1990-11-27
Category : Science
ISBN : 9789813103863

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Covariant Operator Formalism Of Gauge Theories And Quantum Gravity by Nakanishi Noboru,Ojima Izumi Pdf

This book provides a thorough description of the manifestly covariant canonical formalism of the abelian and non-abelian gauge theories and quantum gravity. The emphasis is on its non-perturbative nature and the non-use of the path-integral approach. The formalism presented here is extremely beautiful and transparent.

Author : Samuele Silvervalle
Publisher : Springer Nature
Page : 197 pages
File Size : 52,7 Mb
Release : 2024-02-11
Category : Science
ISBN : 9783031489945

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Isolated Objects in Quadratic Gravity by Samuele Silvervalle Pdf

One of the main unanswered question of modern Physics is "How does gravity behave at small scales?". The aim of this thesis is to illustrate in a comprehensive but accessible way how to look for deviations from Einstein's theory of General Relativity in this regime, looking at the simplest celestial bodies: static and spherically symmetric ones. With a conservative and bottom-up approach, at smaller scales the first corrections to the action of General Relativity are generally considered to be terms quadratic in the curvature tensors; while these modifications do not cure the inconsistency between gravity and quantum mechanics, the solutions of this theory are plausible candidates to be the first-order corrections of the classical ones. Even with such simple modifications, a striking picture emerges from the study of isolated objects: the unique Schwarzschild solution of General Relativity is only a rare bird in the set of solutions, with non-Schwarzschild black holes, wormholes and naked singularities appearing as possible substitutes. Tailored to graduate students and researchers entering this field, this thesis shows how to construct these new solutions from action principles, how to characterize their metric, how to study their physical properties, such as their stability or Thermodynamics, and how to look for phenomenological signatures.

Author : Astrid Eichhorn,Benjamin Bahr,Antonio D. Pereira
Publisher : Frontiers Media SA
Page : 298 pages
File Size : 43,9 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 : Steffen Gielen,Sylvain Carrozza,Daniele Oriti
Publisher : MDPI
Page : 338 pages
File Size : 53,7 Mb
Release : 2020-07-01
Category : Mathematics
ISBN : 9783039361786

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Progress in Group Field Theory and Related Quantum Gravity Formalisms by Steffen Gielen,Sylvain Carrozza,Daniele Oriti Pdf

Following the fundamental insights from quantum mechanics and general relativity, geometry itself should have a quantum description; the search for a complete understanding of this description is what drives the field of quantum gravity. Group field theory is an ambitious framework in which theories of quantum geometry are formulated, incorporating successful ideas from the fields of matrix models, ten-sor models, spin foam models and loop quantum gravity, as well as from the broader areas of quantum field theory and mathematical physics. This special issue collects recent work in group field theory and these related approaches, as well as other neighbouring fields (e.g., cosmology, quantum information and quantum foundations, statistical physics) to the extent that these are directly relevant to quantum gravity research.