Kip Stephen Thorne Becoming One of the Youngest Full Professors in the History of the California Institute of Technology
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Quantum Black Holes
Quantum Black Holes Xavier Calmet Physics & Astronomy University of Sussex Standard Model of particle physics It is described by a quantum field theory. Like athletes, coupling constants run (with energy)…. fast or slow When does gravity become important? The Planck mass is the energy scale A grand unification? at which quantum Is there actually only gravitational effects one fundamental interaction? become important. Doing quantum gravity is challenging • We do not know how to do calculations in quantum gravity. • Unifying gravity and quantum mechanics is difficult. • One can however show a few features such a theory should have, most notably: there is a minimal length in nature (e.g. XC, M. Graesser and S. Hsu) which corresponds to the size of the quantum fluctuations of spacetime itself. • New tools/theories are needed: string theory, loop quantum gravity, noncommutative geometry, nonperturbative quantum gravity… maybe something completely different. Quantization of gravity is an issue in the high energy regime which is tough to probe experimentally Dimensional analysis: 19 MP ~10 GeV but we shall see that it does not need to be the case. Since we do not have data: thought experiments can give us some clues. Why gravity do we need to quantize gravity? One example: linearized gravity coupled to matter (described by a quantum field theory) is problematic: See talk of Claus Kiefer We actually do not even know at what energy scale quantum gravity becomes strong! Let me give you two examples TeV gravity extra-dimensions where MP is the effective Planck scale in 4-dim ADD brane world RS warped extra-dimension Running of Newton’s constant XC, Hsu & Reeb (2008) • Consider GR with a massive scalar field • Let me consider the renormalization of the Planck mass: Like any other coupling constant: Newton’s constant runs! Theoretical physics can lead to anything… even business ideas! A large hidden sector! • Gravity can be strong at 1 TeV if Newton’s constant runs fast somewhere between eV range and 1 TeV. -
Chairman of the Opening Session
The Universe had (probably) an origin: on singularity theorems & quantum fluctuations Emilio Elizalde ICE/CSIC & IEEC Campus UAB, Barcelona Cosmology and the Quantum Vacuum III, Benasque, Sep 4-10, 2016 Some facts (a few rather surprising...) • Adam Riess, NP 2011, at Starmus (Tenerife), about Hubble: • “Hubble obtained the distances and redshifts of distant nebulae…” • “Hubble discovered that the Universe was expanding…” • No mention to Vesto Slipher, an extraordinary astronomer • Brian Schmidt, NP 2011, at Starmus (Tenerife) & Lisa Randall, Harvard U, in Barcelona, about Einstein: SHOES- • “Einstein was the first to think about the possibility of a ‘dark energy’…” Supernovae • No mention to Fritz Zwicky, another extraordinary astronomer • Fritz Zwicky discovered dark matter in the early 1930s while studying how galaxies move within the Coma Cluster • He was also the first to postulate and use nebulae as gravitational lenses (1937) • How easily* brilliant astronomers get dismissed • How easily* scientific myths arise *in few decades How did the “Big Bang” get its name ? http://www.bbc.co.uk/science/space/universe/scientists/fred_hoyle • Sir Fred Hoyle (1915–2001) English astronomer noted primarily for the theory of stellar nucleosynthesis (1946,54 groundbreaking papers) • Work on Britain's radar project with Hermann Bondi and Thomas Gold • William Fowler NP’83: “The concept of nucleosynthesis in stars was first established by Hoyle in 1946” • He found the idea universe had a beginning to be pseudoscience, also arguments for a creator, “…for it's an irrational process, and can't be described in scientific terms”; “…belief in the first page of Genesis” • Hoyle-Gold-Bondi 1948 steady state theory, “creation or C-field” • BBC radio's Third Programme broadcast on 28 Mar 1949: “… for this to happen you would need such a Big Bang!” Thus: Big Bang = Impossible blow!! But now: Big Bang ≈ Inflation ! • Same underlying physics as in steady state theory, “creation or C-field” • Richard C. -
The Second-Order Correction to the Energy and Momentum in Plane Symmetric Gravitational Waves Like Spacetimes
S S symmetry Article The Second-Order Correction to the Energy and Momentum in Plane Symmetric Gravitational Waves Like Spacetimes Mutahir Ali *, Farhad Ali , Abdus Saboor, M. Saad Ghafar and Amir Sultan Khan Department of Mathematics, Kohat University of Science and Technology, Kohat 26000, Pakistan; [email protected] (F.A.); [email protected] (A.S.); [email protected] (M.S.G.); [email protected] (A.S.K.) * Correspondence: [email protected] Received: 5 December 2018; Accepted: 22 January 2019; Published: 13 February 2019 Abstract: This research provides second-order approximate Noether symmetries of geodetic Lagrangian of time-conformal plane symmetric spacetime. A time-conformal factor is of the form ee f (t) which perturbs the plane symmetric static spacetime, where e is small a positive parameter that produces perturbation in the spacetime. By considering the perturbation up to second-order in e in plane symmetric spacetime, we find the second order approximate Noether symmetries for the corresponding Lagrangian. Using Noether theorem, the corresponding second order approximate conservation laws are investigated for plane symmetric gravitational waves like spacetimes. This technique tells about the energy content of the gravitational waves. Keywords: Einstein field equations; time conformal spacetime; approximate conservation of energy 1. Introduction Gravitational waves are ripples in the fabric of space-time produced by some of the most violent and energetic processes like colliding black holes or closely orbiting black holes and neutron stars (binary pulsars). These waves travel with the speed of light and depend on their sources [1–5]. The study of these waves provide us useful information about their sources (black holes and neutron stars). -
What Is the Universe Made Of? How Old Is the Universe?
What is the Universe made of? How old is it? Charles H. Lineweaver University of New South Wales ABSTRACT For the past 15 years most astronomers have assumed that 95% of the Universe was in some mysterious form of cold dark matter. They also assumed that the cosmo- logical constant, ΩΛ, was Einstein’s biggest blunder and could be ignored. However, recent measurements of the cosmic microwave background combined with other cos- mological observations strongly suggest that 75% of the Universe is made of cosmo- logical constant (vacuum energy), while only 20% is made of non-baryonic cold dark matter. Normal baryonic matter, the stuff most physicists study, makes up about 5% of the Universe. If these results are correct, an unknown 75% of the Universe has been identified. Estimates of the age of the Universe depend upon what it is made of. Thus, our new inventory gives us a new age for the Universe: 13.4 ± 1.6 Gyr. “The history of cosmology shows us that in every age devout people believe that they have at last discovered the true nature of the Universe.” (E. Harrison in Cosmology: The Science of the Universe 1981) 1 Progress A few decades ago cosmology was laughed at for being the only science with no data. Cosmology was theory-rich but data-poor. It attracted armchair enthusiasts spouting speculations without data to test them. It was the only science where the errors could be kept in the exponents – where you could set the speed of light c =1, not for dimensionless convenience, but because the observations were so poor that it didn’t matter. -
HOMOGENEOUS EINSTEIN METRICS on SU(N) MANIFOLDS, HOOP CONJECTURE for BLACK RINGS, and ERGOREGIONS in MAGNETISED BLACK HOLE SPACE
HOMOGENEOUS EINSTEIN METRICS ON SU(n) MANIFOLDS, HOOP CONJECTURE FOR BLACK RINGS, AND ERGOREGIONS IN MAGNETISED BLACK HOLE SPACETIMES A Dissertation by ABID HASAN MUJTABA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved by: Chair of Committee, Christopher Pope Committee Members, Bhaskar Dutta Stephen Fulling Ergin Sezgin Head of Department, George R. Welch May 2013 Major Subject: Physics Copyright 2013 Abid Hasan Mujtaba ABSTRACT This Dissertation covers three aspects of General Relativity: inequivalent Einstein metrics on Lie Group Manifolds, proving the Hoop Conjecture for Black Rings, and investigating ergoregions in magnetised black hole spacetimes. A number of analytical and numerical techniques are employed to that end. It is known that every compact simple Lie Group admits a bi-invariant homogeneous Ein- stein metric. We use two ans¨atzeto probe the existence of additional inequivalent Einstein metrics on the Lie Group SU(n). We provide an explicit construction of 2k + 1 and 2k inequivalent Einstein metrics on SU(2k) and SU(2k + 1) respectively. We prove the Hoop Conjecture for neutral and charged, singly and doubly rotating black rings. This allows one to determine whether a rotating mass distribution has an event horizon, that it is in fact a black ring. We investigate ergoregions in magnetised black hole spacetimes. We show that, in general, rotating charged black holes (Kerr-Newman) immersed in an external magnetic field have ergoregions that extend to infinity near the central axis unless we restrict the charge to q = amB and keep B below a maximal value. -
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 . -
Geometrical Inequalities Bounding Angular Momentum and Charges in General Relativity
Living Rev Relativ (2018) 21:5 https://doi.org/10.1007/s41114-018-0014-7 REVIEW ARTICLE Geometrical inequalities bounding angular momentum and charges in General Relativity Sergio Dain1 · María Eugenia Gabach-Clement1 Received: 10 October 2017 / Accepted: 1 June 2018 © The Author(s) 2018 Abstract Geometrical inequalities show how certain parameters of a physical system set restrictions on other parameters. For instance, a black hole of given mass can not rotate too fast, or an ordinary object of given size can not have too much electric charge. In this article, we are interested in bounds on the angular momentum and electromagnetic charges, in terms of total mass and size. We are mainly concerned with inequalities for black holes and ordinary objects. The former are the most studied systems in this context in General Relativity, and where most results have been found. Ordinary objects, on the other hand, present numerous challenges and many basic questions concerning geometrical estimates for them are still unanswered. We present the many results in these areas. We make emphasis in identifying the mathematical conditions that lead to such estimates, both for black holes and ordinary objects. Keywords Geometrical inequalities · Black holes · Ordinary objects The important moments in life are the ones we share with others. Sergio Dain This article is dedicated to the memory of Sergio Dain and Marcus Ansorg. Sergio Dain: Deceased. B María Eugenia Gabach-Clement [email protected] 1 Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba, Instituto de Física Enrique Gaviola, Consejo Nacional de Investigaciones Científicas y Técnicas, Córdoba, Argentina 123 5 Page 2 of 74 S. -
Science & ROGER PENROSE
Science & ROGER PENROSE Live Webinar - hosted by the Center for Consciousness Studies August 3 – 6, 2021 9:00 am – 12:30 pm (MST-Arizona) each day 4 Online Live Sessions DAY 1 Tuesday August 3, 2021 9:00 am to 12:30 pm MST-Arizona Overview / Black Holes SIR ROGER PENROSE (Nobel Laureate) Oxford University, UK Tuesday August 3, 2021 9:00 am – 10:30 am MST-Arizona Roger Penrose was born, August 8, 1931 in Colchester Essex UK. He earned a 1st class mathematics degree at University College London; a PhD at Cambridge UK, and became assistant lecturer, Bedford College London, Research Fellow St John’s College, Cambridge (now Honorary Fellow), a post-doc at King’s College London, NATO Fellow at Princeton, Syracuse, and Cornell Universities, USA. He also served a 1-year appointment at University of Texas, became a Reader then full Professor at Birkbeck College, London, and Rouse Ball Professor of Mathematics, Oxford University (during which he served several 1/2-year periods as Mathematics Professor at Rice University, Houston, Texas). He is now Emeritus Rouse Ball Professor, Fellow, Wadham College, Oxford (now Emeritus Fellow). He has received many awards and honorary degrees, including knighthood, Fellow of the Royal Society and of the US National Academy of Sciences, the De Morgan Medal of London Mathematical Society, the Copley Medal of the Royal Society, the Wolf Prize in mathematics (shared with Stephen Hawking), the Pomeranchuk Prize (Moscow), and one half of the 2020 Nobel Prize in Physics, the other half shared by Reinhard Genzel and Andrea Ghez. -
Rainer Weiss, Professor of Physics Emeritus and 2017 Nobel Laureate
Giving to the Department of Physics by Erin McGrath RAINER WEISS ’55, PHD ’62 Bryce Vickmark Rai Weiss has established a fellowship in the Physics Department because he is eternally grateful to his advisor, the late Jerrold Zacharias, for all that he did for Rai, so he knows firsthand the importance of supporting graduate students. Rainer Weiss, Professor of Physics Emeritus and 2017 Nobel Laureate. Rainer “Rai” Weiss was born in Berlin, Germany in 1932. His father was a physician and his mother was an actress. His family was forced out of Germany by the Nazis since his father was Jewish and a Communist. Rai, his mother and father fled to Prague, Czecho- slovakia. In 1937 a sister was born in Prague. In 1938, after Chamberlain appeased Hitler by effectively giving him Czechoslovakia, the family was able to obtain visas to enter the United States through the Stix Family in St. Louis, who were giving bond to professional Jewish emigrants. When Rai was 21 years-old, he visited Mrs. Stix and thanked her for what she had done for his family. The family immigrated to New York City. Rai’s father had a hard time passing the medi- cal boards because of his inability to answer multiple choice exams. His mother, who Rai says “held the family together,” worked in a number of retail stores. Through the services of an immigrant relief organization Rai received a scholarship to attend the prestigious Columbia Grammar School. At the end of 1945, when Rai was 13 years old, he became fascinated with electronics and music. -
Tinkering with Time the NEW TIME TRAVELERS: a JOURNEY to the on Our FRONTIERS of PHYSICS by DAVID TOOMEY Bookshelf W
BOOKS & ARTS Tinkering with time THE NEW TIME TRAVELERS: A JOURNEY TO THE On our FRONTIERS OF PHYSICS BY DAVID TOOMEY bookshelf W. W. Norton & Co.: 2007. 320 pp. $25.95 Years ago, David Toomey picked up H. G. Wells’ moving clocks tick slowly, making time travel The Time Machine and couldn’t put it down. to the future possible. We now know a number The Mathematics of He was most interested in the drawing-room of solutions to Einstein’s equations of general Egypt, Mesopotamia, discussion between the time traveller and his relativity (1915) that are sufficiently twisted to China, India, and Islam: friends in which time as a fourth dimension was allow time travel to the past: Kurt Gödel’s 1949 A Sourcebook discussed, but wanted to know more about just rotating universe; the Morris–Thorne–Yurtsever edited by Victor J. Katz how that time machine might work. Toomey was wormhole (1988); the Tipler–van Stockum infinite therefore delighted to learn that that drawing- rotating cylinder, moving cosmic strings (myself), Princeton Univ. Press: room conversation continues today — this time the rotating black-hole interior (Brandon Carter), 2007. 685 pp. $75 among physicists. a Roman ring of wormholes (Matt Visser), the We’re aware that Toomey captures well the personalities Everett–Alcubierre warp drive, my and Li–Xin Li’s the ancient cultures of the ‘new time travelers’ — those physicists self-creating universe; Amos Ori’s torus; and were mathematically interested in whether time travel to the past is others. The book discusses all of these. advanced. Now possible — from Stephen Hawking’s sense of But can a time machine really be constructed? translations of early texts humour to Kip Thorne’s penchant for placing Hawking, like one of the time traveller’s sceptical from five key regions are scientific bets. -
ACCRETION INTO and EMISSION from BLACK HOLES Thesis By
ACCRETION INTO AND EMISSION FROM BLACK HOLES Thesis by Don Nelson Page In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy California Institute of Technology Pasadena, California 1976 (Submitted May 20, 1976) -ii- ACKNOHLEDG:-IENTS For everything involved during my pursuit of a Ph. D. , I praise and thank my Lord Jesus Christ, in whom "all things were created, both in the heavens and on earth, visible and invisible, whether thrones or dominions or rulers or authorities--all things have been created through Him and for Him. And He is before all things, and in Him all things hold together" (Colossians 1: 16-17) . But He is not only the Creator and Sustainer of the universe, including the physi cal laws which rule and their dominion the spacetime manifold and its matter fields ; He is also my personal Savior, who was "wounded for our transgressions , ... bruised for our iniquities, .. and the Lord has lald on Him the iniquity of us all" (Isaiah 53:5-6). As the Apostle Paul expressed it shortly after Isaiah ' s prophecy had come true at least five hundred years after being written, "God demonstrates His own love tmvard us , in that while we were yet sinners, Christ died for us" (Romans 5 : 8) . Christ Himself said, " I have come that they may have life, and have it to the full" (John 10:10) . Indeed Christ has given me life to the full while I have been at Caltech, and I wish to acknowledge some of the main blessings He has granted: First I thank my advisors , KipS. -
MATTERS of GRAVITY, a Newsletter for the Gravity Community, Number 4
MATTERS OF GRAVITY Number 4 Fall 1994 Table of Contents Editorial ................................................... ................... 2 Correspondents ................................................... ............ 2 Gravity news: Report on the APS Topical Group in Gravitation, Beverly Berger ............. 3 Research briefs: Gravitational Microlensing and the Search for Dark Matter: A Personal View, Bohdan Paczynski .......................................... 5 Laboratory Gravity: The G Mystery and Intrinsic Spin Experiments, Riley Newman ............................... 11 LIGO Project update, Stan Whitcomb ....................................... 15 Conference Reports: PASCOS ’94, Peter Saulson .................................................. 16 The Vienna meeting, P. Aichelburg, R. Beig .................................. 19 The Pitt Binary Black Hole Grand Challenge Meeting, Jeff Winicour ......... 20 International Symposium on Experimental Gravitation, Nathiagali, Pakistan, Munawar Karim ....................................... 22 arXiv:gr-qc/9409004v1 2 Sep 1994 10th Pacific Coast Gravity Meeting , Jim Isenberg ........................... 23 Editor: Jorge Pullin Center for Gravitational Physics and Geometry The Pennsylvania State University University Park, PA 16802-6300 Fax: (814)863-9608 Phone (814)863-9597 Internet: [email protected] 1 Editorial The newsletter strides on. I had to perform some pushing around and arm-twisting to get articles for this number. I wish to remind everyone that suggestions and ideas for contributions are especially welcome. The newsletter is growing rather weak on the theoretical side. Keep those suggestions coming! I put together this newsletter mostly on a palmtop computer while travelling, with some contributions arriving the very day of publication (on which, to complicate matters, I was giving a talk at a conference, my email reader crashed and our network went down). One of the contributions is a bit longer than the usual format. Again it is my fault for failing to warn the author in due time.