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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 -
Faceting Space(Time): Regge's View of Geometry
Faceting space(time): Regge’s view of geometry Annalisa Marzuoli, Dipartimento di Matematica, Pavia University Curved surfaces as ‘simple’ models of curved spacetimes in Einstein’s General Relativity (Gauss geometries) The curvature of a generic smooth surface is perceived through its embedding into the 3D Euclidean space Looking at different regions three types of Gauss model geometries can be recognized The saddle surface (negative Gauss curvature) The surface of a sphere The Euclidean plane (positive Gauss is flat, i.e. its curvature) curvature is zero Principal curvatures are defined through ‘extrinsic properties’ of the surface, which is bent as seen in the ambient 3D space Glimpse definition In every point consider the tangent plane and the normal vector to the surface. (Any pair of) normal planes intersect the surface in curved lines. By resorting to the notion of osculating circle, the curvature of these embedded curves is evaluated (in the point). CASES: • > 0 and equal to 1/r • < 0 and equal to -1/r • = 0 r: radius of the osculating circle (Th.) There are only two distinct and mutually ortogonal principal directions in each point of an embedded surface, or: every direction is principal Principal Saddle surface: the principal curvatures curvatures have opposite sign (modulus) K1 = + 1/r1 K2 = - 1/r2 K1 = 1/r1 Sphere of radius r: K2 = 1/r2 K1 = K2 = 1/r > 0 (r1, r2 :radii of the All principal osculating circles) curvatures are equal in each Plane: limiting case point of the sphere r → ∞ (K1 = K2 = 0) Gauss curvature & the theorema -
Regge Finite Elements with Applications in Solid Mechanics and Relativity
Regge Finite Elements with Applications in Solid Mechanics and Relativity A DISSERTATION SUBMITTED TO THE FACULTY OF THE GRADUATE SCHOOL OF THE UNIVERSITY OF MINNESOTA BY Lizao Li IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF Doctor of Philosophy Advisor: Prof. Douglas N. Arnold May 2018 © Lizao Li 2018 ALL RIGHTS RESERVED Acknowledgements I would like to express my sincere gratitude to my advisor Prof. Douglas Arnold, who taught me how to be a mathematician: diligence in thought and clarity in communication (I am still struggling with both). I am also grateful for his continuous guidance, help, support, and encouragement throughout my graduate study and the writing of this thesis. i Abstract This thesis proposes a new family of finite elements, called generalized Regge finite el- ements, for discretizing symmetric matrix-valued functions and symmetric 2-tensor fields. We demonstrate its effectiveness for applications in computational geometry, mathemati- cal physics, and solid mechanics. Generalized Regge finite elements are inspired by Tullio Regge’s pioneering work on discretizing Einstein’s theory of general relativity. We analyze why current discretization schemes based on Regge’s original ideas fail and point out new directions which combine Regge’s geometric insight with the successful framework of finite element analysis. In particular, we derive well-posed linear model problems from general relativity and propose discretizations based on generalized Regge finite elements. While the first part of the thesis generalizes Regge’s initial proposal and enlarges its scope to many other applications outside relativity, the second part of this thesis represents the initial steps towards a stable structure-preserving discretization of the Einstein’s field equation. -
Highlights Se- Mathematics and Engineering— the Lead Signers of the Letter Exhibit
June 2003 NEWS Volume 12, No.6 A Publication of The American Physical Society http://www.aps.org/apsnews Nobel Laureates, Industry Leaders Petition April Meeting Prizes & Awards President to Boost Science and Technology Prizes and Awards were presented to seven- Sixteen Nobel Laureates in that “unless remedied, will affect call for “a Presidential initiative for teen recipients at the Physics and sixteen industry lead- our scientific and technological FY 2005, following on from your April meeting in Philadel- ers have written to President leadership, thereby affecting our budget of FY 2004, and focusing phia. George W. Bush to urge increas- economy and national security.” on the long-term research portfo- After the ceremony, ing funding for physical sciences, The letter, which is dated April lios of DOE, NASA, and the recipients and their environmental sciences, math- 14th, also indicates that “the Department of Commerce, in ad- guests gathered at the ematics, computer science and growth in expert personnel dition to NSF and NIH,” that, Franklin Institute for a engineering. abroad, combined with the di- “would turn around a decade-long special reception. The letter, reinforcing a recent minishing numbers of Americans decline that endangers the future Photo Credit: Stacy Edmonds of Edmonds Photography Council of Advisors on Science and entering the physical sciences, of our nation.” The top photo shows four of the five women recipients in front of a space-suit Technology report, highlights se- mathematics and engineering— The lead signers of the letter exhibit. They are (l to r): Geralyn “Sam” Zeller (Tanaka Award); Chung-Pei rious funding problems in the an unhealthy trend—is leading were Burton Richter, director Michele Ma (Maria-Goeppert Mayer Award); Yvonne Choquet-Bruhat physical sciences and related fields corporations to locate more of emeritus of SLAC, and Craig (Heineman Prize); and Helen Edwards (Wilson Prize). -
*Impaginazione OK
Ministero per i Beni e le Attività Culturali Direzione Generale per i Beni Librari e gli Istituti Culturali Comitato Nazionale per le celebrazioni del centenario della nascita di Enrico Fermi Proceedings of the International Conference “Enrico Fermi and the Universe of Physics” Rome, September 29 – October 2, 2001 Accademia Nazionale dei Lincei Istituto Nazionale di Fisica Nucleare SIPS Proceedings of the International Conference “Enrico Fermi and the Universe of Physics” Rome, September 29 – October 2, 2001 2003 ENEA Ente per le Nuove tecnologie, l’Energia e l’Ambiente Lungotevere Thaon di Revel, 76 00196 - Roma ISBN 88-8286-032-9 Honour Committee Rettore dell’Università di Roma “La Sapienza” Rettore dell’Università degli Studi di Roma “Tor Vergata” Rettore della Terza Università degli Studi di Roma Presidente del Consiglio Nazionale delle Ricerche (CNR) Presidente dell’Ente per le Nuove tecnologie, l’Energia e l’Ambiente (ENEA) Presidente dell’Istituto Nazionale di Fisica Nucleare (INFN) Direttore Generale del Consiglio Europeo di Ricerche Nucleari (CERN) Presidente dell’Istituto Nazionale di Fisica della Materia (INFM) Presidente dell’Agenzia Italiana Nucleare (AIN) Presidente della European Physical Society (EPS) Presidente dell’Accademia Nazionale dei Lincei Presidente dell’Accademia Nazionale delle Scienze detta dei XL Presidente della Società Italiana di Fisica (SIF) Presidente della Società Italiana per il Progresso delle Scienze (SIPS) Direttore del Dipartimento di Fisica dell’Università di Roma “La Sapienza” Index 009 A Short -
Black Holes and Qubits
Subnuclear Physics: Past, Present and Future Pontifical Academy of Sciences, Scripta Varia 119, Vatican City 2014 www.pas.va/content/dam/accademia/pdf/sv119/sv119-duff.pdf Black Holes and Qubits MICHAEL J. D UFF Blackett Labo ratory, Imperial C ollege London Abstract Quantum entanglement lies at the heart of quantum information theory, with applications to quantum computing, teleportation, cryptography and communication. In the apparently separate world of quantum gravity, the Hawking effect of radiating black holes has also occupied centre stage. Despite their apparent differences, it turns out that there is a correspondence between the two. Introduction Whenever two very different areas of theoretical physics are found to share the same mathematics, it frequently leads to new insights on both sides. Here we describe how knowledge of string theory and M-theory leads to new discoveries about Quantum Information Theory (QIT) and vice-versa (Duff 2007; Kallosh and Linde 2006; Levay 2006). Bekenstein-Hawking entropy Every object, such as a star, has a critical size determined by its mass, which is called the Schwarzschild radius. A black hole is any object smaller than this. Once something falls inside the Schwarzschild radius, it can never escape. This boundary in spacetime is called the event horizon. So the classical picture of a black hole is that of a compact object whose gravitational field is so strong that nothing, not even light, can escape. Yet in 1974 Stephen Hawking showed that quantum black holes are not entirely black but may radiate energy, due to quantum mechanical effects in curved spacetime. In that case, they must possess the thermodynamic quantity called entropy. -
Lab Partners: NSF and DOE
Volume 19 FRIDAY, APRIL 5, 1996 Number 7 Lab Partners: NSF and DOE by Leila Belkora, Office of Public Affairs experiments have had co-spokesmen from NSF- funded university groups. n a spring day in Chicago, if you long for NSF also funds fixed-target experiments and Othe crack of the bat and the scent of mustard special projects at Fermilab. The agency supports on hotdogs, head to Wrigley Field. In the seventh groups at KTeV and NuTeV, where experi- inning stretch you’ll sing a chorus of “Take Me menters hope to shed light on CP violation and Out to the Ball Game,” along with announcer neutrino-nucleon scattering, respectively. Two Harry Caray; baseball at Wrigley just wouldn’t be experiments related to charm quarks, E831 and the same without it. After the game, should you E835, are supported in part by NSF. This year, travel about 40 miles west to Fermilab, approximately 70 graduate students are receiv- you’d find another essential pair- ing their training in NSF-funded ing: Fermilab depends on research groups both at collider funding from the Depart- and fixed-target experi- ment of Energy, but ments. On a smaller scale, high-energy physics NSF grants to Fermilab here would be incom- augment research in plete without the cosmology and facili- support of the tate international National Science collaborations in Foundation, as well. particle physics with I nside NSF’s largest India and Korea. f contribution at In dollars, Fermilab is to the col- NSF’s contribution lider program. At to the national high- Wonyong Lee DZero, seven NSF-sup- energy physics program Profile ported groups built the is about 10 percent that 2 central drift chamber, the of DOE. -
The Struggle for Quantum Theory 47 5.1Aliensignals
Fundamental Forces of Nature The Story of Gauge Fields This page intentionally left blank Fundamental Forces of Nature The Story of Gauge Fields Kerson Huang Massachusetts Institute of Technology, USA World Scientific N E W J E R S E Y • L O N D O N • S I N G A P O R E • B E I J I N G • S H A N G H A I • H O N G K O N G • TA I P E I • C H E N N A I Published by World Scientific Publishing Co. Pte. Ltd. 5 Toh Tuck Link, Singapore 596224 USA office: 27 Warren Street, Suite 401-402, Hackensack, NJ 07601 UK office: 57 Shelton Street, Covent Garden, London WC2H 9HE British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. FUNDAMENTAL FORCES OF NATURE The Story of Gauge Fields Copyright © 2007 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. This book, or parts thereof, may not be reproduced in any form or by any means, electronic or mechanical, including photocopying, recording or any information storage and retrieval system now known or to be invented, without written permission from the Publisher. For photocopying of material in this volume, please pay a copying fee through the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, USA. In this case permission to photocopy is not required from the publisher. ISBN-13 978-981-270-644-7 ISBN-10 981-270-644-5 ISBN-13 978-981-270-645-4 (pbk) ISBN-10 981-270-645-3 (pbk) Printed in Singapore. -
Snowmass01 Masterreg DB 16May.FP5
SNOWMASS 2001 Summary: Working Groups Name Nametag Institution EMail M1 M2 M3 M4 M5 M6 T1 T2 T3 T4 T5 T6 T7 T8 T9 E1 E2 E3 E4 E5 E6 E7 P1 P2 P3 P4 P5 ,1 Abe Toshinori Stanford Linear Accelerator Center [email protected] 1 ,2 Adams Todd Florida State University [email protected] 11 1 ,3 Adolphsen Chris Stanford Linear Accelerator Center [email protected] 11 ,4 Akerib Dan Case Western Reserve University [email protected] 11 ,5 Albright Carl H. Northern Illinois University [email protected] 11 ,6 Albrow Michael Fermi National Accelerator Laboratory [email protected] 11 11 ,7 Allen Matthew Stanford Linear Accelerator Center [email protected] 1 ,8 Appel Jeffrey Fermi National Accelerator Laboratory [email protected] 11 1 1 111 ,9 Artuso Marina Syracuse University [email protected] 1 ,10 Asiri Fred Stanford University [email protected] 1 ,11 Asztalos Steve Massachusetts Institute of Technology [email protected] 11 1 ,12 Atwood David Iowa State University [email protected] 11 13, Augustin Jean-Eude LPNHE Paris [email protected] 11 1 1 1 ,14 Avery Paul University of Florida [email protected] 11 1 1 ,15 Babukhadia Levan State University of New York, Stony [email protected] 1 1 111 ,16 Bachacou Henri Lawrence Berkeley National Laboratory [email protected] 111 1 ,17 Baer Howard Florida State University [email protected] 11 1 11 ,18 Baker Winslow Fermi National Accelerator Laboratory [email protected] 11 ,19 Balazs Csaba University of Hawaii [email protected] 111 ,20 Barber Desmond DESY, Hamburg [email protected] -
Arxiv:1410.1486V2 [Gr-Qc] 26 Aug 2015
October 2014 Black Hole Thermodynamics S. Carlip∗ Department of Physics University of California Davis, CA 95616 USA Abstract The discovery in the early 1970s that black holes radiate as black bodies has radically affected our understanding of general relativity, and offered us some early hints about the nature of quantum gravity. In this chapter I will review the discovery of black hole thermodynamics and summarize the many indepen- dent ways of obtaining the thermodynamic and (perhaps) statistical mechanical properties of black holes. I will then describe some of the remaining puzzles, including the nature of the quantum microstates, the problem of universality, and the information loss paradox. arXiv:1410.1486v2 [gr-qc] 26 Aug 2015 ∗email: [email protected] 1 Introduction The surprising discovery that black holes behave as thermodynamic objects has radically affected our understanding of general relativity and its relationship to quantum field theory. In the early 1970s, Bekenstein [1, 2] and Hawking [3, 4] showed that black holes radiate as black bodies, with characteristic temperatures and entropies ~κ Ahor kTH = ;SBH = ; (1.1) 2π 4~G where κ is the surface gravity and Ahor is the area of the horizon. These quantities appear to be inherently quantum gravitational, in the sense that they depend on both Planck's constant ~ and Newton's constant G. The resulting black body radiation, Hawking radiation, has not yet been directly observed: the temperature of an astrophysical black hole is on the order of a microkelvin, far lower than the cosmic microwave background temperature. But the Hawking temperature and the Bekenstein-Hawking entropy have been derived in so many independent ways, in different settings and with different assumptions, that it seems extraordinarily unlikely that they are not real. -
Arxiv:1202.4545V2 [Physics.Hist-Ph] 23 Aug 2012
The Relativity of Existence Stuart B. Heinrich [email protected] October 31, 2018 Abstract Despite the success of modern physics in formulating mathematical theories that can predict the outcome of experiments, we have made remarkably little progress towards answering the most fundamental question of: why is there a universe at all, as opposed to nothingness? In this paper, it is shown that this seemingly mind-boggling question has a simple logical answer if we accept that existence in the universe is nothing more than mathematical existence relative to the axioms of our universe. This premise is not baseless; it is shown here that there are indeed several independent strong logical arguments for why we should believe that mathematical existence is the only kind of existence. Moreover, it is shown that, under this premise, the answers to many other puzzling questions about our universe come almost immediately. Among these questions are: why is the universe apparently fine-tuned to be able to support life? Why are the laws of physics so elegant? Why do we have three dimensions of space and one of time, with approximate locality and causality at macroscopic scales? How can the universe be non-local and non-causal at the quantum scale? How can the laws of quantum mechanics rely on true randomness? 1 Introduction can seem astonishing that anything exists” [73, p.24]. Most physicists and cosmologists are equally perplexed. Over the course of modern history, we have seen advances in Richard Dawkins has called it a “searching question that biology, chemistry, physics and cosmology that have painted rightly calls for an explanatory answer” [26, p.155], and Sam an ever-clearer picture of how we came to exist in this uni- Harris says that “any intellectually honest person will admit verse.