What If There Was No Big Bang?
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Inflation, Large Branes, and the Shape of Space
Inflation, Large Branes, and the Shape of Space Brett McInnes National University of Singapore email: [email protected] ABSTRACT Linde has recently argued that compact flat or negatively curved spatial sections should, in many circumstances, be considered typical in Inflationary cosmologies. We suggest that the “large brane instability” of Seiberg and Witten eliminates the negative candidates in the context of string theory. That leaves the flat, compact, three-dimensional manifolds — Conway’s platycosms. We show that deep theorems of Schoen, Yau, Gromov and Lawson imply that, even in this case, Seiberg-Witten instability can be avoided only with difficulty. Using a specific cosmological model of the Maldacena-Maoz type, we explain how to do this, and we also show how the list of platycosmic candidates can be reduced to three. This leads to an extension of the basic idea: the conformal compactification of the entire Euclidean spacetime also has the topology of a flat, compact, four-dimensional space. arXiv:hep-th/0410115v2 19 Oct 2004 1. Nearly Flat or Really Flat? Linde has recently argued [1] that, at least in some circumstances, we should regard cosmological models with flat or negatively curved compact spatial sections as the norm from an Inflationary point of view. Here we wish to argue that cosmic holography, in the novel form proposed by Maldacena and Maoz [2], gives a deep new interpretation of this idea, and also sharpens it very considerably to exclude the negative case. This focuses our attention on cosmological models with flat, compact spatial sections. Current observations [3] show that the spatial sections of our Universe [as defined by observers for whom local isotropy obtains] are fairly close to being flat: the total density parameter Ω satisfies Ω = 1.02 0.02 at 95% confidence level, if we allow the imposition ± of a reasonable prior [4] on the Hubble parameter. -
Eternal Inflation and Its Implications
IOP PUBLISHING JOURNAL OF PHYSICS A: MATHEMATICAL AND THEORETICAL J. Phys. A: Math. Theor. 40 (2007) 6811–6826 doi:10.1088/1751-8113/40/25/S25 Eternal inflation and its implications Alan H Guth Center for Theoretical Physics, Laboratory for Nuclear Science, and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA E-mail: [email protected] Received 8 February 2006 Published 6 June 2007 Online at stacks.iop.org/JPhysA/40/6811 Abstract Isummarizetheargumentsthatstronglysuggestthatouruniverseisthe product of inflation. The mechanisms that lead to eternal inflation in both new and chaotic models are described. Although the infinity of pocket universes produced by eternal inflation are unobservable, it is argued that eternal inflation has real consequences in terms of the way that predictions are extracted from theoretical models. The ambiguities in defining probabilities in eternally inflating spacetimes are reviewed, with emphasis on the youngness paradox that results from a synchronous gauge regularization technique. Although inflation is generically eternal into the future, it is not eternal into the past: it can be proven under reasonable assumptions that the inflating region must be incomplete in past directions, so some physics other than inflation is needed to describe the past boundary of the inflating region. PACS numbers: 98.80.cQ, 98.80.Bp, 98.80.Es 1. Introduction: the successes of inflation Since the proposal of the inflationary model some 25 years ago [1–4], inflation has been remarkably successful in explaining many important qualitative and quantitative properties of the universe. In this paper, I will summarize the key successes, and then discuss a number of issues associated with the eternal nature of inflation. -
Is String Theory Holographic? 1 Introduction
Holography and large-N Dualities Is String Theory Holographic? Lukas Hahn 1 Introduction1 2 Classical Strings and Black Holes2 3 The Strominger-Vafa Construction3 3.1 AdS/CFT for the D1/D5 System......................3 3.2 The Instanton Moduli Space.........................6 3.3 The Elliptic Genus.............................. 10 1 Introduction The holographic principle [1] is based on the idea that there is a limit on information content of spacetime regions. For a given volume V bounded by an area A, the state of maximal entropy corresponds to the largest black hole that can fit inside V . This entropy bound is specified by the Bekenstein-Hawking entropy A S ≤ S = (1.1) BH 4G and the goings-on in the relevant spacetime region are encoded on "holographic screens". The aim of these notes is to discuss one of the many aspects of the question in the title, namely: "Is this feature of the holographic principle realized in string theory (and if so, how)?". In order to adress this question we start with an heuristic account of how string like objects are related to black holes and how to compare their entropies. This second section is exclusively based on [2] and will lead to a key insight, the need to consider BPS states, which allows for a more precise treatment. The most fully understood example is 1 a bound state of D-branes that appeared in the original article on the topic [3]. The third section is an attempt to review this construction from a point of view that highlights the role of AdS/CFT [4,5]. -
2012-2013 Chair James Rosenzweig
Department of Physics Astronomy ANNUAL REPORT 2013 219728_AnnualReport.indd 1 11/18/13 4:02 PM UCLA Physics and Astronomy Department 2012-2013 Chair James Rosenzweig Chief Administrative Officer Will Spencer Feature Article Eric Hudson Editorial Assistants Corinna Koehnenkamp, D.L. MacLaughlan-Dumes, Laurie Ultan-Thomas Design Mary Jo Robertson © 2013 by the Regents of the University of California All rights reserved. Requests for additional copies of the publication UCLA Department of Physics and Astronomy 2012-2013 Annual Report may be sent to: Office of the Chair UCLA Department of Physics and Astronomy 430 Portola Plaza Box 951547 Los Angeles California 90095-1547 For more information on the Department see our website: http://www.pa.ucla.edu/ UCLA DEPARTMENT OF PHYSICS & ASTRONOMY 219728_AnnualReport.indd 2 11/18/13 4:02 PM Department of Physics Astronomy& 2013 Annual Report UNIVERSITY OF CALIFORNIA, LOS ANGELES 219728_AnnualReport.indd 3 11/18/13 4:02 PM CONTENTS FEATURE ARTICLE: P.7 “Harnessing quantum interactions for the future of science and technology” GIVING TO THE DEPARTMENT P.15 UCLA ALUMNI P.18 ASTRONOMY & ASTROPHYSICS P.19 ASTROPARTICLE PHYSICS P.31 PHYSICS RESEARCH HIGHLIGHTS P.37 PHYSICS & ASTRONOMY FACULTY/RESEARCHERS P.60 DEPARTMENT NEWS P.61 OUTREACH-ASTRONOMY LIVE P. 64 GRADUATION 2012-13 P.66 219728_AnnualReport.indd 4 11/18/13 4:02 PM Message from the Chair As Chair of the UCLA Department of Physics and Astronomy, it is with pride that I present to you our 2013 Annual Report. This document is intended to give an overview of the departmental accomplishments recorded in the last year, extending from recog- nition of faculty excellence in teaching and research, to the welcoming of new members to our ranks. -
Reversed out (White) Reversed
Berkeley rev.( white) Berkeley rev.( FALL 2014 reversed out (white) reversed IN THIS ISSUE Berkeley’s Space Sciences Laboratory Tabletop Physics Bringing More Women into Physics ALUMNI NEWS AND MORE! Cover: The MAVEN satellite mission uses instrumentation developed at UC Berkeley's Space Sciences Laboratory to explore the physics behind the loss of the Martian atmosphere. It’s a continuation of Berkeley astrophysicist Robert Lin’s pioneering work in solar physics. See p 7. photo credit: Lockheed Martin Physics at Berkeley 2014 Published annually by the Department of Physics Steven Boggs: Chair Anil More: Director of Administration Maria Hjelm: Director of Development, College of Letters and Science Devi Mathieu: Editor, Principal Writer Meg Coughlin: Design Additional assistance provided by Sarah Wittmer, Sylvie Mehner and Susan Houghton Department of Physics 366 LeConte Hall #7300 University of California, Berkeley Berkeley, CA 94720-7300 Copyright 2014 by The Regents of the University of California FEATURES 4 12 18 Berkeley’s Space Tabletop Physics Bringing More Women Sciences Laboratory BERKELEY THEORISTS INVENT into Physics NEW WAYS TO SEARCH FOR GOING ON SIX DECADES UC BERKELEY HOSTS THE 2014 NEW PHYSICS OF EDUCATION AND SPACE WEST COAST CONFERENCE EXPLORATION Berkeley theoretical physicists Ashvin FOR UNDERGRADUATE WOMEN Vishwanath and Surjeet Rajendran IN PHYSICS Since the Space Lab’s inception are developing new, small-scale in 1959, Berkeley physicists have Women physics students from low-energy approaches to questions played important roles in many California, Oregon, Washington, usually associated with large-scale of the nation’s space-based scientific Alaska, and Hawaii gathered on high-energy particle experiments. -
Our Cosmic Origins
Chapter 5 Our cosmic origins “In the beginning, the Universe was created. This has made a lot of people very angry and has been widely regarded as a bad move”. Douglas Adams, in The Restaurant at the End of the Universe “Oh no: he’s falling asleep!” It’s 1997, I’m giving a talk at Tufts University, and the legendary Alan Guth has come over from MIT to listen. I’d never met him before, and having such a luminary in the audience made me feel both honored and nervous. Especially nervous. Especially when his head started slumping toward his chest, and his gaze began going blank. In an act of des- peration, I tried speaking more enthusiastically and shifting my tone of voice. He jolted back up a few times, but soon my fiasco was complete: he was o↵in dreamland, and didn’t return until my talk was over. I felt deflated. Only much later, when we became MIT colleagues, did I realize that Alan falls asleep during all talks (except his own). In fact, my grad student Adrian Liu pointed out that I’ve started doing the same myself. And that I’ve never noticed that he does too because we always go in the same order. If Alan, I and Adrian sit next to each other in that order, we’ll infallibly replicate a somnolent version of “the wave” that’s so popular with soccer spectators. I’ve come to really like Alan, who’s as warm as he’s smart. Tidiness isn’t his forte, however: the first time I visited his office, I found most of the floor covered with a thick layer of unopened mail. -
Higgs Inflation
Higgs inflation Javier Rubio Institut fur¨ Theoretische Physik, Ruprecht-Karls-Universitat¨ Heidelberg, Philosophenweg 16, 69120 Heidelberg, Germany —————————————————————————————————————————— Abstract The properties of the recently discovered Higgs boson together with the absence of new physics at collider experiments allows us to speculate about consistently extending the Standard Model of particle physics all the way up to the Planck scale. In this context, the Standard Model Higgs non- minimally coupled to gravity could be responsible for the symmetry properties of the Universe at large scales and for the generation of the primordial spectrum of curvature perturbations seeding structure formation. We overview the minimalistic Higgs inflation scenario, its predictions, open issues and extensions and discuss its interplay with the possible metastability of the Standard Model vacuum. —————————————————————————————————————————— arXiv:1807.02376v3 [hep-ph] 13 Mar 2019 Email: [email protected] 1 Contents 1 Introduction and summary3 2 General framework7 2.1 Induced gravity . .7 2.2 Higgs inflation from approximate scale invariance . .8 2.3 Tree-level inflationary predictions . 11 3 Effective field theory interpretation 14 3.1 The cutoff scale . 14 3.2 Relation between high- and low-energy parameters . 16 3.3 Potential scenarios and inflationary predictions . 17 3.4 Vacuum metastability and high-temperature effects . 21 4 Variations and extensions 22 4.1 Palatini Higgs inflation . 23 4.2 Higgs-Dilaton model . 24 5 Concluding remarks 26 6 Acknowledgments 26 2 1 Introduction and summary Inflation is nowadays a well-established paradigm [1–6] able to explain the flatness, homogene- ity and isotropy of the Universe and the generation of the primordial density fluctuations seeding structure formation [7–10]. -
Hawking Radiation and Black Hole Thermodynamics
HAWKING RADIATION AND BLACK HOLE THERMODYNAMICS ∗ Don N. Page † Institute for Theoretical Physics Department of Physics, University of Alberta Edmonton, Alberta, Canada T6G 2J1 (2004 September 3; additional section added 2004 December 31 ‡) Abstract An inexhaustive review of Hawking radiation and black hole thermody- namics is given, focusing especially upon some of the historical aspects as seen from the biased viewpoint of a minor player in the field on and off for the past thirty years. arXiv:hep-th/0409024v3 31 Dec 2004 ∗Alberta-Thy-18-04, hep-th/0409024, review article solicited for a celebratory Focus Issue on Relativity, “Spacetime 100 Years Later,” to be published in New Journal of Physics. †Internet address: [email protected] ‡On this date the author reached an age which is an integer divisor of the number of references. 1 1 Historical Background Black holes are perhaps the most perfectly thermal objects in the universe, and yet their thermal properties are not fully understood. They are described very accurately by a small number of macroscopic parameters (e.g., mass, angular mo- mentum, and charge), but the microscopic degrees of freedom that lead to their thermal behavior have not yet been adequately identified. Strong hints of the thermal properties of black holes came from the behavior of their macroscopic properties that were formalized in the (classical) four laws of black hole mechanics [1], which have analogues in the corresponding four laws of thermodynamics: The zeroth law of black hole mechanics is that the surface gravity κ of a stationary black hole is constant over its event horizon [2, 1]. -
The University of Tokyo's Newly Founded Institute for the Physics
hosted by IPMU was held on 17 - 21 with new projects. The success of the News December 2007. The workshop,“ Focus workshop also clarified the importance Week on LHC Phenomenology”, was of follow-up visitor programs, such as organized by Mihoko Nojiri (PI of IPMU) one month stays to finalize the projects and held at the IPMU, Research Center started in this meeting.” Building, on the Kashiwa campus. Many theorists found the discussion The Large Hadron Collider (LHC) at with experimentalists extremely CERN in Switzerland will start operating important, and vice verse.“ We in 2008. The aim of the meeting was to developed a consensus that it is bring together leading experimentalists important to set a series of workshops and phenomenologists working on LHC, to understand phenomena at the LHC to come up with new idea on physics and to maximize the performance of beyond the standard model. To reach the new physics searches,”remarked Launch of IPMU this goal, it is necessary to understand Nojiri. The University of Tokyo’s newly phenomena in the standard model: founded Institute for the Physics and deep theoretical understanding of the Mathematics of the Universe (IPMU) , standard model, and thus processes was launched on October 1, 2007. and responses involved in the LHC IPMU has been approved as one of the experiments, is essential to identify World Premier International Research effects of the new physics in the Center Initiatives (WPI) of the Ministry experiments. of Education, Culture, Sports, Science The following invited speakers with a and Technology (MEXT). IPMU is an range of expertise were invited. -
Shamit Kachru Professor of Physics and Director, Stanford Institute for Theoretical Physics
Shamit Kachru Professor of Physics and Director, Stanford Institute for Theoretical Physics CONTACT INFORMATION • Administrative Contact Dan Moreau Email [email protected] Bio BIO Starting fall of 2021, I am winding down a term as chair of physics and then taking an extended sabbatical/leave. My focus during this period will be on updating my background and competence in rapidly growing new areas of interest including machine learning and its application to problems involving large datasets. My recent research interests have included mathematical and computational studies of evolutionary dynamics; field theoretic condensed matter physics, including study of non-Fermi liquids and fracton phases; and mathematical aspects of string theory. I would characterize my research programs in these three areas as being in the fledgling stage, relatively recently established, and well developed, respectively. It is hard to know what the future holds, but you can get some idea of the kinds of things I work on by looking at my past. Highlights of my past research include: - The discovery of string dualities with 4d N=2 supersymmetry, and their use to find exact solutions of gauge theories (with Cumrun Vafa) - The construction of the first examples of AdS/CFT duality with reduced supersymmetry (with Eva Silverstein) - Foundational papers on string compactification in the presence of background fluxes (with Steve Giddings and Joe Polchinski) - Basic models of cosmic acceleration in string theory (with Renata Kallosh, Andrei Linde, and Sandip Trivedi) -
MIT Briefing Book 2015 April Edition
MIT Briefing Book 2015 April edition Massachusetts Institute of Technology MIT Briefing Book © 2015, Massachusetts Institute of Technology April 2015 Cover images: Christopher Harting Massachusetts Institute of Technology 77 Massachusetts Avenue Cambridge, Massachusetts 02139-4307 Telephone Number 617.253.1000 TTY 617.258.9344 Website http://web.mit.edu/ The Briefing Book is researched and written by a variety of MIT faculty and staff, in particular the members of the Office of the Provost’s Institutional Research group, Industrial Liaison Program, Student Financial Services, and the MIT Washington Office. Executive Editors Maria T. Zuber, Vice President for Research [email protected] William B. Bonvillian, Director, MIT Washington Office [email protected] Editors Shirley Wong [email protected] Lydia Snover, to whom all questions should be directed [email protected] 2 MIT Briefing Book MIT Senior Leadership President Vice President for Finance L. Rafael Reif Glen Shor Chairman of the Corporation Director, Lincoln Laboratory Robert B. Millard Eric D. Evans Provost Dean, School of Architecture and Planning Martin A. Schmidt Hashim Sarkis Chancellor Dean, School of Engineering Cynthia Barnhart Ian A. Waitz Executive Vice President and Treasurer Dean, School of Humanities, Arts, and Social Sciences Israel Ruiz Deborah K. Fitzgerald Vice President for Research Dean, School of Science Maria T. Zuber Michael Sipser Vice President Dean, Sloan School of Management Claude R. Canizares David C. Schmittlein Vice President and General Counsel Associate Provost Mark DiVincenzo Karen Gleason Chancellor for Academic Advancement Associate Provost W. Eric L. Grimson Philip S. Khoury Vice President Director of Libraries Kirk D. Kolenbrander Chris Bourg Vice President for Communications Institute Community and Equity Officer Nathaniel W. -
Particle Physics Detector in Space
Particle physics detector in space QED IN BULGARIA STARING AT THE SUN HADRON THERAPY Researchers are still pushing at How will Gran Sasso's Borexino The Proton-Ion Medical Machine the frontiers of QED, as a workshop experiment work and what will it tell Study is exploring how particle physics in Bulgaria revealed us about the nature of neutrinos? can benefit medical treatment All the F.W. Bel I (s) and Whistles. RS -232I/O Port Built-in Rechargeable Battery Min/Maxl Peak Hold 0.25% DC Accuracy Frequency Range DC-20 kHz The New6000Series Gauss/Teslameter Delivers Laboratory Accuracy in a Portable Package You spoke and we listened! The New Model 6010 is the As with all F.W. Bell products, you can expect a superior latest development in the measurement of magnetic flux level of performance, satisfaction and support that can come density using F.W. Bell's state-of-the-art Hall-effect only from a world leader. Look to F.W. Bell when quality and technology. performance matter most. The Model 6010 performs Magnetic field measurements Act Now! from zero to 300 kG (30 T) over 6 ranges with a resolution Special Introductory Free Probe Offer! of 1 mG (0.1 JJT). The Model 6010 measures both DC & Call Today at (407) 678-6900 USA or True RMS AC magnetic fields, at frequencies up to 20 kHz, Go to the Web! www.fwbell.com/html/cerncourier.html with a basic DC accuracy of 0.25%. The Model 6010 provides readings in Gauss, Tesla & Ampere/Meters. The new 6000 Series Hall-effect probe features F.W.