Asymptotic Safety and Black Holes

Asymptotic Safety and Black Holes PDF Author: Kevin Falls
Publisher: Springer Science & Business Media
ISBN: 3319012940
Category : Science
Languages : en
Pages : 196

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Book Description
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.

Asymptotic Safety and Black Holes

Asymptotic Safety and Black Holes PDF Author: Kevin Falls
Publisher: Springer Science & Business Media
ISBN: 3319012940
Category : Science
Languages : en
Pages : 196

Get Book Here

Book Description
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.

An Introduction To Covariant Quantum Gravity And Asymptotic Safety

An Introduction To Covariant Quantum Gravity And Asymptotic Safety PDF Author: Roberto Percacci
Publisher: World Scientific
ISBN: 9813207191
Category : Science
Languages : en
Pages : 313

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Book Description
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.

Regular Black Holes

Regular Black Holes PDF Author: Cosimo Bambi
Publisher: Springer Nature
ISBN: 9819915961
Category : Science
Languages : en
Pages : 505

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Book Description
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.

Fundamental Aspects of Asymptotic Safety in Quantum Gravity

Fundamental Aspects of Asymptotic Safety in Quantum Gravity PDF Author: Zoë H. Slade
Publisher: Springer
ISBN: 3030195074
Category : Science
Languages : en
Pages : 143

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Book Description
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.

General Relativity; an Einstein Centenary Survey Part 2

General Relativity; an Einstein Centenary Survey Part 2 PDF Author: Hawking, Stephen W. Hawking
Publisher:
ISBN: 9780521138017
Category : Black holes (Astronomy)
Languages : ja
Pages : 1064

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Book Description


Asymptotically Safe Gravity

Asymptotically Safe Gravity PDF Author: Alessia Benedetta Platania
Publisher: Springer
ISBN: 3319987941
Category : Science
Languages : en
Pages : 149

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Book Description
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.

Coarse Graining in Quantum Gravity: Bridging the Gap between Microscopic Models and Spacetime-Physics

Coarse Graining in Quantum Gravity: Bridging the Gap between Microscopic Models and Spacetime-Physics PDF Author: Astrid Eichhorn
Publisher: Frontiers Media SA
ISBN: 2889710491
Category : Science
Languages : en
Pages : 298

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Book Description


Quantum Gravity and the Functional Renormalization Group

Quantum Gravity and the Functional Renormalization Group PDF Author: Martin Reuter
Publisher: Cambridge University Press
ISBN: 1108608124
Category : Science
Languages : en
Pages : 357

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Book Description
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.

Quantum Gravity and the Functional Renormalization Group

Quantum Gravity and the Functional Renormalization Group PDF Author: Martin Reuter
Publisher: Cambridge University Press
ISBN: 1107107326
Category : Science
Languages : en
Pages : 357

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

Focus on Black Hole Research

Focus on Black Hole Research PDF Author: Paul V. Kreitler
Publisher: Nova Publishers
ISBN: 9781594544606
Category : Science
Languages : en
Pages : 198

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Book Description
A black hole is a point of extreme mass in space-time with a radius, or event horizon, inside of which all electromagnetic radiation (including light) is trapped by gravity. A black hole is an extremely compact object, collapsed by gravity which has overcome electric and nuclear forces. It is believed that stars appreciably larger than the Sun, once they have exhausted all their nuclear fuel, collapse to form black holes: they are "black" because no light escapes their intense gravity. Material attracted to a black hole, though, gains enormous energy and can radiate part of it before being swallowed up. Some astronomers believe that enormously massive black holes exist in the centre of our galaxy and of other galaxies. This new book brings together leading research from through-out the world.