UCLA TEP Seminar Archives Spring 2020
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Particles-Versus-Strings.Pdf
Particles vs. strings http://insti.physics.sunysb.edu/~siegel/vs.html In light of the huge amount of propaganda and confusion regarding string theory, it might be useful to consider the relative merits of the descriptions of the fundamental constituents of matter as particles or strings. (More-skeptical reviews can be found in my physics parodies.A more technical analysis can be found at "Warren Siegel's research".) Predictability The main problem in high energy theoretical physics today is predictions, especially for quantum gravity and confinement. An important part of predictability is calculability. There are various levels of calculations possible: 1. Existence: proofs of theorems, answers to yes/no questions 2. Qualitative: "hand-waving" results, answers to multiple choice questions 3. Order of magnitude: dimensional analysis arguments, 10? (but beware hidden numbers, like powers of 4π) 4. Constants: generally low-energy results, like ground-state energies 5. Functions: complete results, like scattering probabilities in terms of energy and angle Any but the last level eventually leads to rejection of the theory, although previous levels are acceptable at early stages, as long as progress is encouraging. It is easy to write down the most general theory consistent with special (and for gravity, general) relativity, quantum mechanics, and field theory, but it is too general: The spectrum of particles must be specified, and more coupling constants and varieties of interaction become available as energy increases. The solutions to this problem go by various names -- "unification", "renormalizability", "finiteness", "universality", etc. -- but they are all just different ways to realize the same goal of predictability. -
Conformal Symmetry in Field Theory and in Quantum Gravity
universe Review Conformal Symmetry in Field Theory and in Quantum Gravity Lesław Rachwał Instituto de Física, Universidade de Brasília, Brasília DF 70910-900, Brazil; [email protected] Received: 29 August 2018; Accepted: 9 November 2018; Published: 15 November 2018 Abstract: Conformal symmetry always played an important role in field theory (both quantum and classical) and in gravity. We present construction of quantum conformal gravity and discuss its features regarding scattering amplitudes and quantum effective action. First, the long and complicated story of UV-divergences is recalled. With the development of UV-finite higher derivative (or non-local) gravitational theory, all problems with infinities and spacetime singularities might be completely solved. Moreover, the non-local quantum conformal theory reveals itself to be ghost-free, so the unitarity of the theory should be safe. After the construction of UV-finite theory, we focused on making it manifestly conformally invariant using the dilaton trick. We also argue that in this class of theories conformal anomaly can be taken to vanish by fine-tuning the couplings. As applications of this theory, the constraints of the conformal symmetry on the form of the effective action and on the scattering amplitudes are shown. We also remark about the preservation of the unitarity bound for scattering. Finally, the old model of conformal supergravity by Fradkin and Tseytlin is briefly presented. Keywords: quantum gravity; conformal gravity; quantum field theory; non-local gravity; super- renormalizable gravity; UV-finite gravity; conformal anomaly; scattering amplitudes; conformal symmetry; conformal supergravity 1. Introduction From the beginning of research on theories enjoying invariance under local spacetime-dependent transformations, conformal symmetry played a pivotal role—first introduced by Weyl related changes of meters to measure distances (and also due to relativity changes of periods of clocks to measure time intervals). -
The Cosmos - Before the Big Bang
From issue 2601 of New Scientist magazine, 28 April 2007, page 28-33 The cosmos - before the big bang How did the universe begin? The question is as old as humanity. Sure, we know that something like the big bang happened, but the theory doesn't explain some of the most important bits: why it happened, what the conditions were at the time, and other imponderables. Many cosmologists think our standard picture of how the universe came to be is woefully incomplete or even plain wrong, and they have been dreaming up a host of strange alternatives to explain how we got here. For the first time, they are trying to pin down the initial conditions of the big bang. In particular, they want to solve the long-standing mystery of how the universe could have begun in such a well- ordered state, as fundamental physics implies, when it seems utter chaos should have reigned. Several models have emerged that propose intriguing answers to this question. One says the universe began as a dense sea of black holes. Another says the big bang was sparked by a collision between two membranes floating in higher-dimensional space. Yet another says our universe was originally ripped from a larger entity, and that in turn countless baby universes will be born from the wreckage of ours. Crucially, each scenario makes unique and testable predictions; observations coming online in the next few years should help us to decide which, if any, is correct. Not that modelling the origin of the universe is anything new. -
Weyl Gauge-Vector and Complex Dilaton Scalar for Conformal Symmetry and Its Breaking
1 Weyl gauge-vector and complex dilaton scalar for conformal symmetry and its breaking Hans C. Ohanian1 Abstract Instead of the scalar “dilaton” field that is usually adopted to construct conformally invariant Lagrangians for gravitation, we here propose a hybrid construction, involving both a complex dilaton scalar and a Weyl gauge- vector, in accord with Weyl’s original concept of a non-Riemannian conformal geometry with a transport law for length and time intervals, for which this gauge vector is required. Such a hybrid construction permits us to avoid the wrong sign of the dilaton kinetic term (the ghost problem) that afflicts the usual construction. The introduction of a Weyl gauge-vector and its interaction with the dilaton also has the collateral benefit of providing an explicit mechanism for spontaneous breaking of the conformal symmetry, whereby the dilaton and the Weyl gauge-vector acquire masses somewhat smaller than mP by the Coleman-Weinberg mechanism. Conformal symmetry breaking is assumed to precede inflation, which occurs later by a separate GUT or electroweak symmetry breaking, as in inflationary models based on the Higgs boson. Keywords Quantum gravity • Conformal invariance • Spontaneous symmetry breaking •Weyl length transport Publication history First arXiv publication [v1] 30 January 2015. The final publication is available at Springer via http://dx.doi.org/10.1007/s10714-016-2023-8 and in General Relativity and Gravitation, March 2016, 48:25. 1 Introduction Modifications of Einstein’s gravitational theory that incorporate local conformal symmetry—that is, invariance 2 (x ) under the transformation g( x ) e g ( x ) , where ()x is an arbitrary real function—have been exploited in attempts at the solution of various of theoretical problems, such as renormalization of the stress tensor, renormalization of quantum gravity, quantum mechanics of black holes, analytic solutions and geodesic completeness in the early universe, and the dynamics that lead to inflation by symmetry breaking. -
Conformally Invariant Equations for Graviton 50 5.1 the Conformally Invariant System of Conformal Degree 1
Conformally Invariant Equations for Graviton Mohsen Fathi Department of Physics, Tehran Central Branch Islamic Azad Univeristy arXiv:1210.3436v3 [physics.gen-ph] 12 Nov 2012 A thesis submitted for the Master degree Master of Science in Physics Tehran, Winter 2010 I am grateful to my supervisor Dr. Mohammad Reza Tanhayi for the helps, supports and scientific training, during this work and thereafter. Abstract Recent astrophysical data indicate that our universe might currently be in a de Sitter (dS) phase. The importance of dS space has been primarily ignited by the study of the inflationary model of the universe and the quantum gravity. As we know Einstein’s theory of gravitation (with a nonzero cosmological constant) can be interpreted as a theory of a metric field; that is, a symmetric tensor field of rank-2 on a fixed de Sitter back- ground. It has been shown the massless spin-2 Fierz-Pauli wave equation (or the linearized Einstein equation) is not conformally invariant. This result is in contrary with what we used to expect for massless theories. In this thesis we obtain conformally invariant wave equation for the massless spin-2 in the dS space. This study is motivated by the belief that confor- mal invariance may be the key to a future theory of quantum gravity. Contents Introduction 1 1 The Lorentz and the conformal groups, and the concept of invari- ance 3 1.1 Grouptheory ............................... 3 1.1.1 Orthogonalgroups ........................ 4 1.1.2 Rotationgroups.......................... 5 1.2 Invarianceunderagroupaction . 7 1.2.1 Invarianceofthelawsofphysics. 7 1.3 TheLorentzgroup ............................ 8 1.4 Theconformalgroup .......................... -
Conformal Gravity Holography in Four Dimensions
Loyola University Chicago Loyola eCommons Physics: Faculty Publications and Other Works Faculty Publications 2014 Conformal Gravity Holography in Four Dimensions Daniel Grumiller Maria Irakleidou Iva Lovrekovic, Robert McNees Loyola University Chicago, [email protected] Follow this and additional works at: https://ecommons.luc.edu/physics_facpubs Part of the Physics Commons Recommended Citation Grumiller, D, M Irakleidou, I Lovrekovic, and R McNees. "Conformal Gravity Holography in Four Dimensions." Physical Review Letters 112, 2014. This Article is brought to you for free and open access by the Faculty Publications at Loyola eCommons. It has been accepted for inclusion in Physics: Faculty Publications and Other Works by an authorized administrator of Loyola eCommons. For more information, please contact [email protected]. This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License. © 2014 American Physical Society. week ending PRL 112, 111102 (2014) PHYSICAL REVIEW LETTERS 21 MARCH 2014 Conformal Gravity Holography in Four Dimensions † ‡ Daniel Grumiller,1,* Maria Irakleidou,1, Iva Lovrekovic,1, and Robert McNees2,§ 1Institute for Theoretical Physics, Vienna University of Technology, Wiedner Hauptstrasse 8–10/136, A-1040 Vienna, Austria 2Department of Physics, Loyola University Chicago, Chicago, Illinois 60660, USA (Received 8 October 2013; published 18 March 2014) We formulate four-dimensional conformal gravity with (anti–)de Sitter boundary conditions that are weaker than Starobinsky boundary conditions, allowing for an asymptotically subleading Rindler term concurrent with a recent model for gravity at large distances. We prove the consistency of the variational principle and derive the holographic response functions. One of them is the conformal gravity version of the Brown–York stress tensor, the other is a “partially massless response”. -
Prospects from Strings and Branes
Prospects from strings and branes Alexander Sevrin Vrije Universiteit Brussel and The International Solvay Institutes for Physics and Chemistry http://tena4.vub.ac.be/ Moriond 2004 Strings and branes… Moriond, March 24, 2004 1 References Not-too-technical review paper, including numerous references: Strings, Gravity and Particle Physics by Augusto Sagnotti and AS In the proceedings of 37th Rencontres de Moriond on Electroweak Interactions and Unified Theories, 2002. e-Print Archive: hep-ex/0209011 Strings and branes… Moriond, March 24, 2004 2 Contents • Dirichlet-branes • D-branes and gauge theories - Worldvolume point of view -AdS/CFT • D-branes and black holes •Cosmology • Some conclusions Strings and branes… Moriond, March 24, 2004 3 Branes Solitons: solutions of the equations of motion with a finite energy(-density) and a mass inversely proportional to the coupling constant. E.g. Scalar field in d = 1 + 1: kink. 12m3 mass = λ Other example in d = 3 + 1: magnetic monopole: 1 mass ∝ 2 gYM Strings and branes… Moriond, March 24, 2004 4 Solitons in string theory: Dirichlet branes Besides the “conventional” fields, such as e.g., gµν (x)=gνµ(x): metric = graviton Φ(x): dilaton, one has RR- potentials as well. E.g. vector potential, A µ : Fµν = ∂µAν − ∂ν Aµ, Aµ → Aµ − ∂µf, Fµν → Fµν . Couples to particles: µ S = q dτ x˙ (τ)Aµ(x(τ)). Z Strings and branes… Moriond, March 24, 2004 5 E.g. 2-form potential, A µ ν = − A ν µ : Fµνρ = ∂µAνρ + ∂ν Aρµ + ∂ρAµν , Aµν → Aµν − ∂µfν + ∂ν fµ,Fµνρ → Fµνρ. Couples to strings: µ ν S = q dτdσ x˙(τ, σ) x0(τ, σ) Aµν (x(τ, σ)). -
Here Is a Printer Friendly Source
13 December 2018 Dear Participants: It is my honor to welcome you to the 15th topical physics conference in the “Miami” series --- a meeting that continues a sixth decade of physics conferences held in south Florida. This year’s meeting is dedicated to the memory of Peter Freund. Peter was a good friend to me and many others at this meeting. He was a frequent participant and he gave strong support for these conferences. Moreover, the current particle theory group at the University of Miami was created in the late 1980s largely due to Peter’s enthusiastic endorsement. Before the current series began in December 2004, the “Coral Gables conferences” were organized by University of Miami faculty from January 1964 to December 2003, often assisted by many faculty from other institutions including many of the organizers of this meeting. In particular, Sydney Meshkov has helped to organize and has attended almost all of these meetings since they began over 50 years ago. His participation again this year continues this remarkable tradition. It is also traditional for these meetings to try to accommodate most if not all requests to speak without having parallel sessions. Once again that will be the case, and once again this year the conference program and other useful information will not be printed and distributed in a binder. This information will only be available, in its entirety, online. See https://cgc.physics.miami.edu/Miami2018.html If you must have a printed copy of the entire program, as well as the other useful information, here is a printer friendly source, https://cgc.physics.miami.edu/2018ConferenceBooklet.pdf If you have any special requirements for your talk, or if you have any questions that the hotel staff cannot answer, please ask any attending local member of the organizing committee, in particular, Jo Ann Curtright (cell phone number 786-200-1480), Thomas Curtright (cell phone number 305-793-4637), as well as Diego Castano, and Stephan Mintz. -
2003-2004Annualreport 001.Pdf
1 TABLE OF CONTENTS I. FORWARD..........................................................................................................................3 II. ORGANIZATION ...............................................................................................................3 A. Staff................................................................................................................................3 B. Departmental Committees for 2003-2004 .....................................................................3 III. FACULTY ...........................................................................................................................5 A. Areas of Specialization ..................................................................................................5 B. Honors and Awards........................................................................................................5 C. Grants and Gifts (awarded 2003-2004)..........................................................................5 D. Proposal Submissions (2003-2004) ...............................................................................6 E. Publications....................................................................................................................7 F. Talks Presented and Meetings Attended........................................................................8 G. Community Service .......................................................................................................9 IV. ACADEMIC ENRICHMENT & SUPPORT -
Annual Report 2010 Report Annual IPMU ANNUAL REPORT 2010 April 2010 April – March 2011March
IPMU April 2010–March 2011 Annual Report 2010 IPMU ANNUAL REPORT 2010 April 2010 – March 2011 World Premier International Institute for the Physics and Mathematics of the Universe (IPMU) Research Center Initiative Todai Institutes for Advanced Study Todai Institutes for Advanced Study The University of Tokyo 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583, Japan TEL: +81-4-7136-4940 FAX: +81-4-7136-4941 http://www.ipmu.jp/ History (April 2010–March 2011) April • Workshop “Recent advances in mathematics at IPMU II” • Press Release “Shape of dark matter distribution” • Mini-Workshop “Cosmic Dust” May • Shaw Prize to David Spergel • Press Release “Discovery of the most distant cluster of galaxies” • Press Release “An unusual supernova may be a missing link in stellar evolution” June • CL J2010: From Massive Galaxy Formation to Dark Energy • Press Conference “Study of type Ia supernovae strengthens the case for the dark energy” July • Institut d’Astrophysique de Paris Medal (France) to Ken’ichi Nomoto • IPMU Day of Extra-galactic Astrophysics Seminars: Chemical Evolution August • Workshop “Galaxy and cosmology with Thirty Meter Telescope (TMT)” September • Subaru Future Instrumentation Workshop • Horiba International Conference COSMO/CosPA October • The 3rd Anniversary of IPMU, All Hands Meeting and Reception • Focus Week “String Cosmology” • Nishinomiya-Yukawa Memorial Prize to Eiichiro Komatsu • Workshop “Evolution of massive galaxies and their AGNs with the SDSS-III/BOSS survey” • Open Campus Day: Public lecture, mini-lecture and exhibits November -
Thesis in Amsterdam
UvA-DARE (Digital Academic Repository) The physics and mathematics of microstates in string theory: And a monstrous Farey tail de Lange, P. Publication date 2016 Document Version Final published version Link to publication Citation for published version (APA): de Lange, P. (2016). The physics and mathematics of microstates in string theory: And a monstrous Farey tail. General rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. UvA-DARE is a service provided by the library of the University of Amsterdam (https://dare.uva.nl) Download date:10 Oct 2021 P a u A dissertation that delves l The Physics & d into physical and e L mathematical aspects of a Microstates Mathematics of n g string theory. In the first e part ot this book, Microstates in T microscopic porperties of h Moonshine e string theoretic black String Theory P h holes are investigated. -
The Birth of String Theory
The Birth of String Theory Edited by Andrea Cappelli INFN, Florence Elena Castellani Department of Philosophy, University of Florence Filippo Colomo INFN, Florence Paolo Di Vecchia The Niels Bohr Institute, Copenhagen and Nordita, Stockholm Contents Contributors page vii Preface xi Contents of Editors' Chapters xiv Abbreviations and acronyms xviii Photographs of contributors xxi Part I Overview 1 1 Introduction and synopsis 3 2 Rise and fall of the hadronic string Gabriele Veneziano 19 3 Gravity, unification, and the superstring John H. Schwarz 41 4 Early string theory as a challenging case study for philo- sophers Elena Castellani 71 EARLY STRING THEORY 91 Part II The prehistory: the analytic S-matrix 93 5 Introduction to Part II 95 6 Particle theory in the Sixties: from current algebra to the Veneziano amplitude Marco Ademollo 115 7 The path to the Veneziano model Hector R. Rubinstein 134 iii iv Contents 8 Two-component duality and strings Peter G.O. Freund 141 9 Note on the prehistory of string theory Murray Gell-Mann 148 Part III The Dual Resonance Model 151 10 Introduction to Part III 153 11 From the S-matrix to string theory Paolo Di Vecchia 178 12 Reminiscence on the birth of string theory Joel A. Shapiro 204 13 Personal recollections Daniele Amati 219 14 Early string theory at Fermilab and Rutgers Louis Clavelli 221 15 Dual amplitudes in higher dimensions: a personal view Claud Lovelace 227 16 Personal recollections on dual models Renato Musto 232 17 Remembering the `supergroup' collaboration Francesco Nicodemi 239 18 The `3-Reggeon vertex' Stefano Sciuto 246 Part IV The string 251 19 Introduction to Part IV 253 20 From dual models to relativistic strings Peter Goddard 270 21 The first string theory: personal recollections Leonard Susskind 301 22 The string picture of the Veneziano model Holger B.