Susskind Lecture Notes General Relativity
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The Future of Fundamental Physics
The Future of Fundamental Physics Nima Arkani-Hamed Abstract: Fundamental physics began the twentieth century with the twin revolutions of relativity and quantum mechanics, and much of the second half of the century was devoted to the con- struction of a theoretical structure unifying these radical ideas. But this foundation has also led us to a number of paradoxes in our understanding of nature. Attempts to make sense of quantum mechanics and gravity at the smallest distance scales lead inexorably to the conclusion that space- Downloaded from http://direct.mit.edu/daed/article-pdf/141/3/53/1830482/daed_a_00161.pdf by guest on 23 September 2021 time is an approximate notion that must emerge from more primitive building blocks. Further- more, violent short-distance quantum fluctuations in the vacuum seem to make the existence of a macroscopic world wildly implausible, and yet we live comfortably in a huge universe. What, if anything, tames these fluctuations? Why is there a macroscopic universe? These are two of the central theoretical challenges of fundamental physics in the twenty-½rst century. In this essay, I describe the circle of ideas surrounding these questions, as well as some of the theoretical and experimental fronts on which they are being attacked. Ever since Newton realized that the same force of gravity pulling down on an apple is also responsible for keeping the moon orbiting the Earth, funda- mental physics has been driven by the program of uni½cation: the realization that seemingly disparate phenomena are in fact different aspects of the same underlying cause. By the mid-1800s, electricity and magnetism were seen as different aspects of elec- tromagnetism, and a seemingly unrelated phenom- enon–light–was understood to be the undulation of electric and magnetic ½elds. -
Quantum Field Theory*
Quantum Field Theory y Frank Wilczek Institute for Advanced Study, School of Natural Science, Olden Lane, Princeton, NJ 08540 I discuss the general principles underlying quantum eld theory, and attempt to identify its most profound consequences. The deep est of these consequences result from the in nite number of degrees of freedom invoked to implement lo cality.Imention a few of its most striking successes, b oth achieved and prosp ective. Possible limitation s of quantum eld theory are viewed in the light of its history. I. SURVEY Quantum eld theory is the framework in which the regnant theories of the electroweak and strong interactions, which together form the Standard Mo del, are formulated. Quantum electro dynamics (QED), b esides providing a com- plete foundation for atomic physics and chemistry, has supp orted calculations of physical quantities with unparalleled precision. The exp erimentally measured value of the magnetic dip ole moment of the muon, 11 (g 2) = 233 184 600 (1680) 10 ; (1) exp: for example, should b e compared with the theoretical prediction 11 (g 2) = 233 183 478 (308) 10 : (2) theor: In quantum chromo dynamics (QCD) we cannot, for the forseeable future, aspire to to comparable accuracy.Yet QCD provides di erent, and at least equally impressive, evidence for the validity of the basic principles of quantum eld theory. Indeed, b ecause in QCD the interactions are stronger, QCD manifests a wider variety of phenomena characteristic of quantum eld theory. These include esp ecially running of the e ective coupling with distance or energy scale and the phenomenon of con nement. -
Introduction to General Relativity
INTRODUCTION TO GENERAL RELATIVITY Gerard 't Hooft Institute for Theoretical Physics Utrecht University and Spinoza Institute Postbox 80.195 3508 TD Utrecht, the Netherlands e-mail: [email protected] internet: http://www.phys.uu.nl/~thooft/ Version November 2010 1 Prologue General relativity is a beautiful scheme for describing the gravitational ¯eld and the equations it obeys. Nowadays this theory is often used as a prototype for other, more intricate constructions to describe forces between elementary particles or other branches of fundamental physics. This is why in an introduction to general relativity it is of importance to separate as clearly as possible the various ingredients that together give shape to this paradigm. After explaining the physical motivations we ¯rst introduce curved coordinates, then add to this the notion of an a±ne connection ¯eld and only as a later step add to that the metric ¯eld. One then sees clearly how space and time get more and more structure, until ¯nally all we have to do is deduce Einstein's ¯eld equations. These notes materialized when I was asked to present some lectures on General Rela- tivity. Small changes were made over the years. I decided to make them freely available on the web, via my home page. Some readers expressed their irritation over the fact that after 12 pages I switch notation: the i in the time components of vectors disappears, and the metric becomes the ¡ + + + metric. Why this \inconsistency" in the notation? There were two reasons for this. The transition is made where we proceed from special relativity to general relativity. -
"Eternal" Questions in the XX-Century Theoretical Physics V
Philosophical roots of the "eternal" questions in the XX-century theoretical physics V. Ihnatovych Department of Philosophy, National Technical University of Ukraine “Kyiv Polytechnic Institute”, Kyiv, Ukraine e-mail: [email protected] Abstract The evolution of theoretical physics in the XX century differs significantly from that in XVII-XIX centuries. While continuous progress is observed for theoretical physics in XVII-XIX centuries, modern physics contains many questions that have not been resolved despite many decades of discussion. Based upon the analysis of works by the founders of the XX-century physics, the conclusion is made that the roots of the "eternal" questions by the XX-century theoretical physics lie in the philosophy used by its founders. The conclusion is made about the need to use the ideas of philosophy that guided C. Huygens, I. Newton, W. Thomson (Lord Kelvin), J. K. Maxwell, and the other great physicists of the XVII-XIX centuries, in all areas of theoretical physics. 1. Classical Physics The history of theoretical physics begins in 1687 with the work “Mathematical Principles of Natural Philosophy” by Isaac Newton. Even today, this work is an example of what a full and consistent outline of the physical theory should be. It contains everything necessary for such an outline – definition of basic concepts, the complete list of underlying laws, presentation of methods of theoretical research, rigorous proofs. In the eighteenth century, such great physicists and mathematicians as Euler, D'Alembert, Lagrange, Laplace and others developed mechanics, hydrodynamics, acoustics and nebular mechanics on the basis of the ideas of Newton's “Principles”. -
The Universe Unveiled Given by Prof Carlo Contaldi
Friends of Imperial Theoretical Physics We are delighted to announce that the first FITP event of 2015 will be a talk entitled The Universe Unveiled given by Prof Carlo Contaldi. The event is free and open to all but please register by visiting the Eventbrite website via http://tinyurl.com/fitptalk2015. Date: 29th April 2015 Venue: Lecture Theatre 1, Blackett Laboratory, Physics Department, ICL Time: 7-8pm followed by a reception in the level 8 Common room Speaker: Professor Carlo Contaldi The Universe Unveiled The past 25 years have seen our understanding of the Universe we live in being revolutionised by a series of stunning observational campaigns and theoretical advances. We now know the composition, age, geometry and evolutionary history of the Universe to an astonishing degree of precision. A surprising aspect of this journey of discovery is that it has revealed some profound conundrums that challenge the most basic tenets of fundamental physics. We still do not understand the nature of 95% of the matter and energy that seems to fill the Universe, we still do not know why or how the Universe came into being, and we have yet to build a consistent "theory of everything" that can describe the evolution of the Universe during the first few instances after the Big Bang. In this lecture I will review what we know about the Universe today and discuss the exciting experimental and theoretical advances happening in cosmology, including the controversy surrounding last year's BICEP2 "discovery". Biography of the speaker: Professor Contaldi gained his PhD in theoretical physics in 2000 at Imperial College working on theories describing the formation of structures in the universe. -
Spacetime Geometry from Graviton Condensation: a New Perspective on Black Holes
Spacetime Geometry from Graviton Condensation: A new Perspective on Black Holes Sophia Zielinski née Müller München 2015 Spacetime Geometry from Graviton Condensation: A new Perspective on Black Holes Sophia Zielinski née Müller Dissertation an der Fakultät für Physik der Ludwig–Maximilians–Universität München vorgelegt von Sophia Zielinski geb. Müller aus Stuttgart München, den 18. Dezember 2015 Erstgutachter: Prof. Dr. Stefan Hofmann Zweitgutachter: Prof. Dr. Georgi Dvali Tag der mündlichen Prüfung: 13. April 2016 Contents Zusammenfassung ix Abstract xi Introduction 1 Naturalness problems . .1 The hierarchy problem . .1 The strong CP problem . .2 The cosmological constant problem . .3 Problems of gravity ... .3 ... in the UV . .4 ... in the IR and in general . .5 Outline . .7 I The classical description of spacetime geometry 9 1 The problem of singularities 11 1.1 Singularities in GR vs. other gauge theories . 11 1.2 Defining spacetime singularities . 12 1.3 On the singularity theorems . 13 1.3.1 Energy conditions and the Raychaudhuri equation . 13 1.3.2 Causality conditions . 15 1.3.3 Initial and boundary conditions . 16 1.3.4 Outlining the proof of the Hawking-Penrose theorem . 16 1.3.5 Discussion on the Hawking-Penrose theorem . 17 1.4 Limitations of singularity forecasts . 17 2 Towards a quantum theoretical probing of classical black holes 19 2.1 Defining quantum mechanical singularities . 19 2.1.1 Checking for quantum mechanical singularities in an example spacetime . 21 2.2 Extending the singularity analysis to quantum field theory . 22 2.2.1 Schrödinger representation of quantum field theory . 23 2.2.2 Quantum field probes of black hole singularities . -
The Anthropic Principle and Multiple Universe Hypotheses Oren Kreps
The Anthropic Principle and Multiple Universe Hypotheses Oren Kreps Contents Abstract ........................................................................................................................................... 1 Introduction ..................................................................................................................................... 1 Section 1: The Fine-Tuning Argument and the Anthropic Principle .............................................. 3 The Improbability of a Life-Sustaining Universe ....................................................................... 3 Does God Explain Fine-Tuning? ................................................................................................ 4 The Anthropic Principle .............................................................................................................. 7 The Multiverse Premise ............................................................................................................ 10 Three Classes of Coincidence ................................................................................................... 13 Can The Existence of Sapient Life Justify the Multiverse? ...................................................... 16 How unlikely is fine-tuning? .................................................................................................... 17 Section 2: Multiverse Theories ..................................................................................................... 18 Many universes or all possible -
The Multiverse: Conjecture, Proof, and Science
The multiverse: conjecture, proof, and science George Ellis Talk at Nicolai Fest Golm 2012 Does the Multiverse Really Exist ? Scientific American: July 2011 1 The idea The idea of a multiverse -- an ensemble of universes or of universe domains – has received increasing attention in cosmology - separate places [Vilenkin, Linde, Guth] - separate times [Smolin, cyclic universes] - the Everett quantum multi-universe: other branches of the wavefunction [Deutsch] - the cosmic landscape of string theory, imbedded in a chaotic cosmology [Susskind] - totally disjoint [Sciama, Tegmark] 2 Our Cosmic Habitat Martin Rees Rees explores the notion that our universe is just a part of a vast ''multiverse,'' or ensemble of universes, in which most of the other universes are lifeless. What we call the laws of nature would then be no more than local bylaws, imposed in the aftermath of our own Big Bang. In this scenario, our cosmic habitat would be a special, possibly unique universe where the prevailing laws of physics allowed life to emerge. 3 Scientific American May 2003 issue COSMOLOGY “Parallel Universes: Not just a staple of science fiction, other universes are a direct implication of cosmological observations” By Max Tegmark 4 Brian Greene: The Hidden Reality Parallel Universes and The Deep Laws of the Cosmos 5 Varieties of Multiverse Brian Greene (The Hidden Reality) advocates nine different types of multiverse: 1. Invisible parts of our universe 2. Chaotic inflation 3. Brane worlds 4. Cyclic universes 5. Landscape of string theory 6. Branches of the Quantum mechanics wave function 7. Holographic projections 8. Computer simulations 9. All that can exist must exist – “grandest of all multiverses” They can’t all be true! – they conflict with each other. -
A Shorter Course of Theoretical Physics Vol. 1. Mechanics and Electrodynamics Vol. 2. Quantum Mechanics Vol. 3. Macroscopic Phys
A Shorter Course of Theoretical Physics IN THREE VOLUMES Vol. 1. Mechanics and Electrodynamics Vol. 2. Quantum Mechanics Vol. 3. Macroscopic Physics A SHORTER COURSE OF THEORETICAL PHYSICS VOLUME 2 QUANTUM MECHANICS BY L. D. LANDAU AND Ε. M. LIFSHITZ Institute of Physical Problems, U.S.S.R. Academy of Sciences TRANSLATED FROM THE RUSSIAN BY J. B. SYKES AND J. S. BELL PERGAMON PRESS OXFORD · NEW YORK · TORONTO · SYDNEY Pergamon Press Ltd., Headington Hill Hall, Oxford Pergamon Press Inc., Maxwell House, Fairview Park, Elmsford, New York 10523 Pergamon of Canada Ltd., 207 Queen's Quay West, Toronto 1 Pergamon Press (Aust.) Pty. Ltd., 19a Boundary Street, Rushcutters Bay, N.S.W. 2011, Australia Copyright © 1974 Pergamon Press Ltd. All Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of Pergamon Press Ltd. First edition 1974 Library of Congress Cataloging in Publication Data Landau, Lev Davidovich, 1908-1968. A shorter course of theoretical physics. Translation of Kratkii kurs teoreticheskoi riziki. CONTENTS: v. 1. Mechanics and electrodynamics. —v. 2. Quantum mechanics. 1. Physics. 2. Mechanics. 3. Quantum theory. I. Lifshits, Evgenii Mikhaflovich, joint author. II. Title. QC21.2.L3513 530 74-167927 ISBN 0-08-016739-X (v. 1) ISBN 0-08-017801-4 (v. 2) Translated from Kratkii kurs teoreticheskoi fiziki, Kniga 2: Kvantovaya Mekhanika IzdateFstvo "Nauka", Moscow, 1972 Printed in Hungary PREFACE THIS book continues with the plan originated by Lev Davidovich Landau and described in the Preface to Volume 1: to present the minimum of material in theoretical physics that should be familiar to every present-day physicist, working in no matter what branch of physics. -
Theoretical Physics Introduction
2 Theoretical Physics Introduction A Single Coupling Constant The gravitational N-body problem can be defined as the challenge to understand the motion of N point masses, acted upon by their mutual gravitational forces (Eq.[1.1]). From the physical point of view a fun- damental feature of these equations is the presence of only one coupling 8 3 1 2 constant: the constant of gravitation, G =6.67 10− cm g− sec− (see Seife 2000 for recent measurements). It is even× possible to remove this altogether by making a choice of units in which G = 1. Matters would be more complicated if there existed some length scale at which the gravitational interaction departed from the inverse square dependence on distance. Despite continuing efforts, no such behaviour has been found (Schwarzschild 2000). The fact that a self-gravitating system of point masses is governed by a law with only one coupling constant (or none, after scaling) has important consequences. In contrast to most macroscopic systems, there is no decoupling of scales. We do not have at our disposal separate dials that can be set in order to study the behaviour of local and global aspects separately. As a consequence, the only real freedom we have, when modeling a self-gravitating system of point masses, is our choice of the value of the dimensionless number N, the number of particles in the system. As we will see, the value of N determines a large number of seemingly independent characteristics of the system: its granularity and thereby its speed of internal heat transport and evolution; the size of the central region of highest density after the system settles down in an asymptotic state; the nature of the oscillations that may occur in this central region; and to a surprisingly weak extent the rate of exponential divergence of nearby trajectories in the system. -
SUPERSYMMETRIC UNIFICATION Savas Dimopoulos+
CERN-TH.7531/94 ) SUPERSYMMETRIC UNIFICATION +) Savas Dimop oulos Theoretical Physics Division, CERN CH - 1211 Geneva23 ABSTRACT The measured value of the weak mixing angle is, at present, the only precise exp erimental indication for physics b eyond the Standard Mo del. It p oints in the direction of Uni ed Theo- ries with Sup ersymmetric particles at accessible energies. We recall the ideas that led to the construction of these theories in 1981. Talk presented at the International Conference on the History of Original Ideas and Basic Discoveries in Particle Physics held at Ettore Ma jorana Centre for Scienti c Culture, Erice, Sicily, July 29-Aug.4 1994. CERN-TH.7531/94 Decemb er 1994 1 Why Sup ersymmetric Uni cation? It is a pleasure to recall the ideas that led to the rst Sup ersymmetric Uni ed Theory and its low energy manifestation, the Sup ersymmetric SU (3) SU (2) U (1) mo del. This theory synthesizes two marvelous ideas, Uni cation [1] and Sup ersymmetry [2, 3 ]. The synthesis is catalyzed by the hierarchy problem [4] which suggests that Sup ersymmetry o ccurs at accessible energies [5]. Since time is short and we are explicitly asked to talk ab out our own contributions I will not cover these imp ortant topics. A lo ok at the the program of this Conference reveals that most other topics covered are textb o ok sub jects, such as Renormalization of the Standard Mo del [6] and Asymptotic Free- dom [7], that are at the foundation of our eld. So it is natural to ask why Sup ersymmetric Uni cation is included in such a distinguished companyofwell-established sub jects? I am not certain. -
PDF Download the Black Hole War : My Battle with Stephen Hawking To
THE BLACK HOLE WAR : MY BATTLE WITH STEPHEN HAWKING TO MAKE THE WORLD SAFE FOR QUANTUM MECHANICS PDF, EPUB, EBOOK Leonard Susskind | 480 pages | 05 Nov 2009 | Little, Brown & Company | 9780316016414 | English | New York, United States The Black Hole War : My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics PDF Book Black Holes and Quantum Physics. Softcover edition. Most scientists didn't recognize the import of Hawking's claims, but Leonard Susskind and Gerard t'Hooft realized the threat, and responded with a counterattack that changed the course of physics. Please follow the detailed Help center instructions to transfer the files to supported eReaders. The Black Hole War is the thrilling story of their united effort to reconcile Hawking's theories of black holes with their own sense of reality, an effort that would eventually result in Hawking admitting he was wrong and Susskind and 't Hooft realizing that our world is a hologram projected from the outer boundaries of space. This is the inside account of the battle over the true nature of black holes—with nothing less than our understanding of the entire universe at stake. From the bestselling author of The White Donkey, a heartbreaking and visceral graphic novel set against the stark beauty of Afghanistan's mountain villages that examines prejudice and the military remnants of colonialism. Most scientists didn't recognize the import of Hawking's claims, but Leonard Susskind and Gerard t'Hooft realized the threat, and responded with a counterattack that changed the course of physics. But really, unlike it sounds, this means that information, or characteristics of an object, must always be preserved according to classical physics theory.