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Stephen Hawking (1942–2018) World-Renowned Physicist Who Defied the Odds
COMMENT OBITUARY Stephen Hawking (1942–2018) World-renowned physicist who defied the odds. hen Stephen Hawking was speech synthesizer processed his words and diagnosed with motor-neuron generated the androidal accent that became disease at the age of 21, it wasn’t his trademark. In this way, he completed his Wclear that he would finish his PhD. Against best-selling book A Brief History of Time all expectations, he lived on for 55 years, (Bantam, 1988), which propelled him to becoming one of the world’s most celebrated celebrity status. IAN BERRY/MAGNUM scientists. Had Hawking achieved equal distinction Hawking, who died on 14 March 2018, was in any other branch of science besides cos- born in Oxford, UK, in 1942 to a medical- mology, it probably would not have had the researcher father and a philosophy-graduate same resonance with a worldwide public. As mother. After attending St Albans School I put it in The Telegraph newspaper in 2007, near London, he earned a first-class degree “the concept of an imprisoned mind roaming in physics from the University of Oxford. He the cosmos” grabbed people’s imagination. began his research career in 1962, enrolling In 1965, Stephen married Jane Wilde. as a graduate student in a group at the Uni- After 25 years of marriage, and three versity of Cambridge led by one of the fathers children, the strain of Stephen’s illness of modern cosmology, Dennis Sciama. and of sharing their home with a team of The general theory of relativity was at that nurses became too much and they sepa- time undergoing a renaissance, initiated in rated, divorcing in 1995. -
CERN Celebrates Discoveries
INTERNATIONAL JOURNAL OF HIGH-ENERGY PHYSICS CERN COURIER VOLUME 43 NUMBER 10 DECEMBER 2003 CERN celebrates discoveries NEW PARTICLES NETWORKS SPAIN Protons make pentaquarks p5 Measuring the digital divide pl7 Particle physics thrives p30 16 KPH impact 113 KPH impact series VISyN High Voltage Power Supplies When the objective is to measure the almost immeasurable, the VISyN-Series is the detector power supply of choice. These multi-output, card based high voltage power supplies are stable, predictable, and versatile. VISyN is now manufactured by Universal High Voltage, a world leader in high voltage power supplies, whose products are in use in every national laboratory. For worldwide sales and service, contact the VISyN product group at Universal High Voltage. Universal High Voltage Your High Voltage Power Partner 57 Commerce Drive, Brookfield CT 06804 USA « (203) 740-8555 • Fax (203) 740-9555 www.universalhv.com Covering current developments in high- energy physics and related fields worldwide CERN Courier (ISSN 0304-288X) is distributed to member state governments, institutes and laboratories affiliated with CERN, and to their personnel. It is published monthly, except for January and August, in English and French editions. The views expressed are CERN not necessarily those of the CERN management. Editor Christine Sutton CERN, 1211 Geneva 23, Switzerland E-mail: [email protected] Fax:+41 (22) 782 1906 Web: cerncourier.com COURIER Advisory Board R Landua (Chairman), P Sphicas, K Potter, E Lillest0l, C Detraz, H Hoffmann, R Bailey -
Supergravity at 40: Reflections and Perspectives(∗)
RIVISTA DEL NUOVO CIMENTO Vol. 40, N. 6 2017 DOI 10.1393/ncr/i2017-10136-6 ∗ Supergravity at 40: Reflections and perspectives( ) S. Ferrara(1)(2)(3)andA. Sagnotti(4) (1) Theoretical Physics Department, CERN CH - 1211 Geneva 23, Switzerland (2) INFN - Laboratori Nazionali di Frascati - Via Enrico Fermi 40 I-00044 Frascati (RM), Italy (3) Department of Physics and Astronomy, Mani L. Bhaumik Institute for Theoretical Physics U.C.L.A., Los Angeles CA 90095-1547, USA (4) Scuola Normale Superiore e INFN - Piazza dei Cavalieri 7, I-56126 Pisa, Italy received 15 February 2017 Dedicated to John H. Schwarz on the occasion of his 75th birthday Summary. — The fortieth anniversary of the original construction of Supergravity provides an opportunity to combine some reminiscences of its early days with an assessment of its impact on the quest for a quantum theory of gravity. 280 1. Introduction 280 2. The early times 282 3. The golden age 283 4. Supergravity and particle physics 284 5. Supergravity and string theory 286 6. Branes and M-theory 287 7. Supergravity and the AdS/CFT correspondence 288 8. Conclusions and perspectives ∗ ( ) Based in part on the talk delivered by S.F. at the “Special Session of the DISCRETE2016 Symposium and the Leopold Infeld Colloquium”, in Warsaw, on December 1 2016, and on a joint CERN Courier article. c Societ`a Italiana di Fisica 279 280 S. FERRARA and A. SAGNOTTI 1. – Introduction The year 2016 marked the fortieth anniversary of the discovery of Supergravity (SGR) [1], an extension of Einstein’s General Relativity [2] (GR) where Supersymme- try, promoted to a gauge symmetry, accompanies general coordinate transformations. -
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]. -
Soft Hair on Black Holes Arxiv:1601.00921V1 [Hep-Th] 5 Jan
Soft Hair on Black Holes Stephen W. Hawkingy, Malcolm J. Perryy and Andrew Strominger∗ yDAMTP, Centre for Mathematical Sciences, University of Cambridge, Cambridge, CB3 0WA UK ∗ Center for the Fundamental Laws of Nature, Harvard University, Cambridge, MA 02138, USA Abstract It has recently been shown that BMS supertranslation symmetries imply an infinite number of conservation laws for all gravitational theories in asymptotically Minkowskian spacetimes. These laws require black holes to carry a large amount of soft (i:e: zero- energy) supertranslation hair. The presence of a Maxwell field similarly implies soft electric hair. This paper gives an explicit description of soft hair in terms of soft gravitons or photons on the black hole horizon, and shows that complete information about their quantum state is stored on a holographic plate at the future boundary of the horizon. Charge conservation is used to give an infinite number of exact relations between the evaporation products of black holes which have different soft hair but are otherwise identical. It is further argued that soft hair which is spatially localized to arXiv:1601.00921v1 [hep-th] 5 Jan 2016 much less than a Planck length cannot be excited in a physically realizable process, giving an effective number of soft degrees of freedom proportional to the horizon area in Planck units. Contents 1 Introduction 1 2 Electromagnetic conservation laws and soft symmetries 4 3 Conservation laws in the presence of black holes 7 4 Black hole evaporation 9 5 Quantum hair implants 12 6 Gauge invariance 14 7 Supertranslations 15 8 Conclusion 17 1 Introduction Forty years ago, one of the authors argued [1] that information is destroyed when a black hole is formed and subsequently evaporates [2, 3]. -
MATTERS of GRAVITY Contents
MATTERS OF GRAVITY The newsletter of the Division of Gravitational Physics of the American Physical Society Number 52 December 2018 Contents DGRAV News: we hear that . , by David Garfinkle ..................... 3 APS April Meeting, by David Garfinkle ................... 4 Editor David Garfinkle Department of Physics Oakland University Rochester, MI 48309 Phone: (248) 370-3411 Internet: garfinkl-at-oakland.edu WWW: http://www.oakland.edu/physics/Faculty/david-garfinkle Associate Editor Greg Comer Department of Physics and Center for Fluids at All Scales, St. Louis University, St. Louis, MO 63103 Phone: (314) 977-8432 Internet: comergl-at-slu.edu WWW: http://www.slu.edu/arts-and-sciences/physics/faculty/comer-greg.php ISSN: 1527-3431 DISCLAIMER: The opinions expressed in the articles of this newsletter represent the views of the authors and are not necessarily the views of APS. The articles in this newsletter are not peer reviewed. 1 Editorial The next newsletter is due June 2019. Issues 28-52 are available on the web at https://files.oakland.edu/users/garfinkl/web/mog/ All issues before number 28 are available at http://www.phys.lsu.edu/mog Any ideas for topics that should be covered by the newsletter should be emailed to me, or Greg Comer, or the relevant correspondent. Any comments/questions/complaints about the newsletter should be emailed to me. A hardcopy of the newsletter is distributed free of charge to the members of the APS Division of Gravitational Physics upon request (the default distribution form is via the web) to the secretary of the Division. It is considered a lack of etiquette to ask me to mail you hard copies of the newsletter unless you have exhausted all your resources to get your copy otherwise. -
Generalizing Entropic Force Formalism
Yongpyung 2012, Greenpia Condo, Feb. 21st 2012 GENERALIZING ENTROPIC FORCE FORMALISM Jin-Ho Cho (Hanyang University) w/ Hosin Gong, Hyosung Kim (POSTECH) Motivation (for the entropic force) Quantum Gravity .....not successful so far the role of gravity in AdS/CFT tree level supergravity (closed string) / quantum SYM (open string) Fundamental or Emergent? Entropic Force rubber band tends to increase the entropy S : larger S : smaller [Halliday et al., Fundamentals of Physics] Verlinde’s Idea [Erik Verlinde, 1001.0785] entropic force : F x = T S 4 4 3 holographic principle : Ac /G~ = N E = NkBT/2 T = ~a/2πkBc entropy change : S =2πkB( x mc/~) 4 4 (for a screen shift x ) 4 Newtonian Physics Newton’s law : (a planar screen) T = ~a/2πckB S =2πkB( x mc/~) 4 4 F x = T S 4 4 ~a 2πkBmc x = 4 2πk c ✓ B ◆✓ ~ ◆ = ma x 4 3 Gravitational force : (a spherical screen) N = Ac /G~ 2 Mc = E = NkBT/2 1 Ac3 ~a r2c2 = = a 2 G 2πc ✓ ~ ◆✓ ◆ G Q1: Cosmological Constant ? g R ab R + ⇤g =8⇡GT ab − 2 ab ab 3 Ac /G~ = N F x = T S S =2πkB( x mc/~) 4 4 E = NkBT/2 4 4 T = ~a/2πkBc ‘Volume Energy’ NkBT E = Mc2 +↵V = 2 N~ a ~a = T = 4⇡c 2⇡ckB 2 Ac a 3 = N = Ac /G~ 4⇡G 4⇡GM 4⇡G↵V a = + A Ac2 Determination of ↵ spherically symmetric case GM 4⇡G↵r a = + = Φ r2 3c2 r GM c2⇤r = Newtonian limit of Einstein eq. r2 − 3 c4 ↵ = ⇤ −4⇡G Einstein equation 4 c NkBT E = Mc2 ⇤V = − 4⇡G 2 c4 k c3 Mc2 ⇤ dV = B TdN = adA − 4⇡G 2 4⇡G Z Z Z 1 a b 1 a b 2 T Tg n ⇠ dV ⇤gabn ⇠ dV ab − 2 ab −4⇡G Z⌃ ✓ ◆ Z⌃ 1 = R na⇠b dV 4⇡G ab Z⌃ Q2: Entropic Coulomb Force ? [JHC & Hyosung Kim, 2012 J. -
Curriculum Vitae
SEBASTIAN DE HARO Curriculum Vitae Assistant Professor in Philosophy of Science at the Institute for Logic, Language and Computation and the Institute of Physics of the University of Amsterdam 1. RESEARCH PROFILE Areas of specialisation: Philosophy of Science, History and Philosophy of Physics, Theoretical Physics Areas of competence: Epistemology, Metaphysics, Ethics, Philosophical and Social Aspects of Information, History of Science, History of Philosophy, Philosophy of Logic and Language, Philosophy of Mathematics 2. PREVIOUS POSITIONS • Lecturer (2009-2020), Amsterdam University College (AUC), University of Amsterdam. Tasks: teaching, curriculum development and evaluation, thesis supervision, member of the BSA committee. Between 2009-2015 I also had tutoring responsibilities. • Lecturer (2019-2020, fixed term), Department of Philosophy, Free University Amsterdam • Lecturer in theoretical physics (fixed term), Institute for Theoretical Physics, Faculty of Science, University of Amsterdam. Teaching, research, thesis supervision. 02/12 - 07/14. • Research associate. Managing editor of Foundations of Physics on behalf of Gerard ’t Hooft, Spinoza Institute/ITP, Utrecht University and Springer Verlag, 2008-2009. Research, managing editorial office, setting up new projects, contact Editorial Board. 3. PUBLICATIONS Total number of citations (all publications): 2,751. i10-index: 33. h-index: 22 Full list of publications and citation information via Google scholar profile: http://scholar.google.nl/citations?user=rmXDqN4AAAAJ&hl=nl&oi=ao Journal articles, book chapters, and book reviews General philosophy of science: journal articles (6) 1. ‘The Empirical Under-determination Argument Against Scientific Realism for Dual Theories’. Erkenntnis, 2021. https://link.springer.com/article/10.1007%2Fs10670-020-00342-0 2. ‘Science and Philosophy: A Love-Hate Relationship’. -
First Annual BHI Conference on Black Holes
The Inaugural Black Hole Initiative Annual Conference Scientific Program First Annual BHI Conference on Black Holes Monday, May 8 and Tuesday, May 9, 2017 Sheraton Commander Hotel, 16 Garden Street, Cambridge, MA Hosted by the Black Hole Initiative, Harvard University http://bhi.fas.harvard.edu/ All talks are 20 minutes (15+5) Sessions held in the George Washington Ballroom Coffee Breaks held in the adjacent Terrace Room Monday, May 8, 9:00AM-5:30PM 9:00-9:10AM Avi Loeb: Welcome Session 1: LIGO Session Chair: Ramesh Narayan 9:10-10:30AM Scott Hughes: Black Hole Physics via Gravitational Waves Dan Holz: LIGO's Black Holes Samaya Nissanke: Follow the Roars and Chirps: The Astrophysics of LIGO’s Binary Black Holes Deirdre Shoemaker: Binary Black Holes 10:30-11:00AM Coffee Break Session 2: General Relativity Session Chair: Ramesh Narayan 11:00-12:00PM Clifford Will: Relativistic Evolution of Orbits Around Spinning Massive Black Holes Emanuele Berti: Testing the Kerr Paradigm with Gravitational Wave Observations Pankaj Joshi: Black Holes and Naked Singularities--The Story So Far 12:00-1:30PM Lunch Break Session 3: Physics Session Chair: Andrew Strominger 1:30-3:00PM Alejandra Castro Anich: Extreme Measures for Extremal Black Holes: Recent Theoretical Developments on Black Hole Entropy Glen Barnich: BMS Current Algebra and Field Dependent Central Extension Stefanos Aretakis: Tails of Linear Waves on Black Holes Monica Guica: The Kerr/CFT Correspondence and String Theory 3:00-3:50PM Coffee Break Session 4: Supermassive Black Holes Session Chair: -
Supersymmetry at Large Distance Scales
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server PUPT-1925 Supersymmetry at Large Distance Scales Herman Verlinde Physics Department, Princeton University, Princeton, NJ 08544 Abstract We propose that the UV/IR relation that underlies the AdS/CFT duality may provide a natural mechanism by which high energy supersymmetry can have large distance conse- quences. We motivate this idea via (a string realization of) the Randall-Sundrum scenario, in which the observable matter is localized on a matter brane separate from the Planck brane. As suggested via the holographic interpretation of this scenario, we argue that the local dynamics of the Planck brane – which determines the large scale 4-d geometry – is protected by the high energy supersymmetry of the dual 4-d theory. With this assumption, we show that the total vacuum energy naturally cancels in the effective 4-d Einstein equa- tion. This cancellation is robust against changes in the low energy dynamics on the matter brane, which gets stabilized via the holographic RG without any additional fine-tuning. 1. Introduction The observed smallness of the cosmological constant requires a remarkable cancellation of all vacuum energy contributions [1]. Supersymmetry seems at present the only known symmetry that could naturally explain this cancellation, but thus far no mechanism for supersymmetry breaking is known that would not destroy this property. Nonetheless, in searching for a possible resolution of the cosmological constant problem, it seems natural to include supersymmetry as a central ingredient. What would then be needed, however, is a mechanism – some UV/IR correspondence – by which the short distance cancellations of supersymmetry can somehow be translated into a long distance stability of the cosmological evolution equations. -
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. -
A Unitary S-Matrix for 2D Black Hole Formation and Evaporation
PUPT-1380 IASSNS-HEP-93/8 February 1993 A Unitary S-matrix for 2D Black Hole Formation and Evaporation Erik Verlinde School of Natural Sciences Institute for Advanced Study Princeton, NJ 08540 and Herman Verlinde Joseph Henry Laboratories Princeton University Princeton, NJ 08544 arXiv:hep-th/9302022v1 7 Feb 1993 Abstract We study the black hole information paradox in the context of a two-dimensional toy model given by dilaton gravity coupled to N massless scalar fields. After making the model well-defined by imposing reflecting boundary conditions at a critical value of the dilaton field, we quantize the theory and derive the quantum S-matrix for the case that N=24. This S-matrix is unitary by construction, and we further argue that in the semiclassical regime it describes the formation and subsequent Hawking evaporation of two-dimensional black holes. Finally, we note an interesting correspondence between the dilaton gravity S-matrix and that of the c = 1 matrix model. 1. Introduction The discovery that black holes can evaporate by emitting thermal radiation has led to a longstanding controversy about whether or not quantum coherence can be maintained in this process. Hawking’s original calculation [1] suggests that an initial state, describing matter collapsing into a black hole, will eventually evolve into a mixed state describing the thermal radiation emitted by the black hole. The quantum physics of black holes thus seems inherently unpredictable. However, this is clearly an unsatisfactory conclusion, and several attempts have been made to find a description of black hole evaporation in accordance with the rules of quantum mechanics [2, 3], but so far all these attempts have run into serious difficulties.