In the Dirac Tradition
Total Page：16
File Type：pdf, Size：1020Kb
Load more
Recommended publications
-
Unrestricted Immigration and the Foreign Dominance Of
Unrestricted Immigration and the Foreign Dominance of United States Nobel Prize Winners in Science: Irrefutable Data and Exemplary Family Narratives—Backup Data and Information Andrew A. Beveridge, Queens and Graduate Center CUNY and Social Explorer, Inc. Lynn Caporale, Strategic Scientific Advisor and Author The following slides were presented at the recent meeting of the American Association for the Advancement of Science. This project and paper is an outgrowth of that session, and will combine qualitative data on Nobel Prize Winners family histories along with analyses of the pattern of Nobel Winners. The first set of slides show some of the patterns so far found, and will be augmented for the formal paper. The second set of slides shows some examples of the Nobel families. The authors a developing a systematic data base of Nobel Winners (mainly US), their careers and their family histories. This turned out to be much more challenging than expected, since many winners do not emphasize their family origins in their own biographies or autobiographies or other commentary. Dr. Caporale has reached out to some laureates or their families to elicit that information. We plan to systematically compare the laureates to the population in the US at large, including immigrants and non‐immigrants at various periods. Outline of Presentation • A preliminary examination of the 609 Nobel Prize Winners, 291 of whom were at an American Institution when they received the Nobel in physics, chemistry or physiology and medicine • Will look at patterns of -
Steven Weinberg Cv Born
STEVEN WEINBERG CV BORN: May 3, 1933, in New York, N.Y. EDUCATION: Cornell University, 1950–1954 (A.B., 1954) Copenhagen Institute for Theoretical Physics, 1954–1955 Princeton University, 1955–1957 (Ph.D.,1957). HONORARY DEGREES: Harvard University, A.M., 1973 Knox College, D.Sc., 1978 University of Chicago, Sc.D., 1978 University of Rochester, Sc.D., l979 Yale University, Sc.D., 1979 City University of New York,Sc.D., 1980 Clark University, Sc.D., 1982 Dartmouth College, Sc.D., 1984 Weizmann Institute, Ph.D. Hon.Caus., 1985 Washington College, D.Litt., 1985 Columbia University, Sc.D., 1990 University of Salamanca, Sc.D., 1992 University of Padua, Ph.D. Hon.Caus., 1992 University of Barcelona, Sc.D., 1996 Bates College, Sc. D., 2002 McGill University, Sc. D., 2003 University of Waterloo, Sc. D., 2004 Renssalear Polytechnic Institue, Sc. D., 2016 Rockefeller University, Sc. D., 2017 PRESENT POSITION: Josey Regental Professor of Science, University of Texas, 1982– PAST POSITIONS: Columbia University, 1957–1959 Lawrence Radiation Laboratory, 1959–1960 University of California, Berkeley, 1960–1969 On leave, Imperial College, London, 1961–1962 Steven Weinberg 2 Became full professor, 1964 On leave, Harvard University, 1966–1967 On leave, Massachusetts Institute of Technology, 1967–1969 Massachusetts Institute of Technology, 1969–1973, Professor of Physics Harvard University, 1973–1983, Higgins Professor of Physics On leave 1976–1977, as Visiting Professor of Physics, Stanford University Smithsonian Astrophysical Observatory, 1973-1983, Senior -
SHELDON LEE GLASHOW Lyman Laboratory of Physics Harvard University Cambridge, Mass., USA
TOWARDS A UNIFIED THEORY - THREADS IN A TAPESTRY Nobel Lecture, 8 December, 1979 by SHELDON LEE GLASHOW Lyman Laboratory of Physics Harvard University Cambridge, Mass., USA INTRODUCTION In 1956, when I began doing theoretical physics, the study of elementary particles was like a patchwork quilt. Electrodynamics, weak interactions, and strong interactions were clearly separate disciplines, separately taught and separately studied. There was no coherent theory that described them all. Developments such as the observation of parity violation, the successes of quantum electrodynamics, the discovery of hadron resonances and the appearance of strangeness were well-defined parts of the picture, but they could not be easily fitted together. Things have changed. Today we have what has been called a “standard theory” of elementary particle physics in which strong, weak, and electro- magnetic interactions all arise from a local symmetry principle. It is, in a sense, a complete and apparently correct theory, offering a qualitative description of all particle phenomena and precise quantitative predictions in many instances. There is no experimental data that contradicts the theory. In principle, if not yet in practice, all experimental data can be expressed in terms of a small number of “fundamental” masses and cou- pling constants. The theory we now have is an integral work of art: the patchwork quilt has become a tapestry. Tapestries are made by many artisans working together. The contribu- tions of separate workers cannot be discerned in the completed work, and the loose and false threads have been covered over. So it is in our picture of particle physics. Part of the picture is the unification of weak and electromagnetic interactions and the prediction of neutral currents, now being celebrated by the award of the Nobel Prize. -
Nobel Prize for Physics, 1979
Nobel Prize for Physics, 1979 Abdus Sal am Physics' most prestigious accolade forces is a significant milestone in goes this year to Sheldon Glashow, the constant quest to describe as Abdus Salam and Steven Weinberg much as possible of the world for their work in elucidating the inter around us from a minimal set of actions of elementary particles, and initial ideas. in particular for the development of 'At first sight there may be little or the theory which unifies the electro no similarity between electromag magnetic and weak forces. netic effects and the phenomena This synthesis of two of the basic associated with weak interactions', forces of nature must be reckoned as wrote Sheldon Glashow in 1960. one of the crowning achievements 'Yet remarkable parallels emerge...' of a century which has already seen Both kinds of interactions affect the birth of both quantum mechanics leptons and hadrons; both appear to and relativity. be 'vector' interactions brought Electromagnetism and the weak about by the exchange of particles force might appear to have little to carrying unit spin and negative pari do with each other. Electromagne ty; both have their own universal tism is our everyday world — it holds coupling constant which governs the atoms together and produces light, strength of the interactions. while the weak force was for a long These vital clues led Glashow to time known only for the relatively propose an ambitious theory which obscure phenomenon of beta-decay attempted to unify the two forces. radioactivity. However there was one big difficul The successful unification of these ty, which Glashow admitted had to two apparently highly dissimilar be put to one side. -
A Question of Quantum Reality 24 September 2020
A question of quantum reality 24 September 2020 virtuality. Bell spent most of his working life at CERN in Geneva, Switzerland, and Bertlmann first met him when he took up a short-term fellowship there in 1978. Bell had first presented his theorem in a seminal paper published in 1964, but this was largely neglected until the 1980s and the introduction of quantum information. Bertlmann discusses the concept of Bell inequalities, which arise through thought experiments in which a pair of spin-½ particles propagate in opposite directions and are measured Credit: Pixabay/CC0 Public Domain by independent observers, Alice and Bob. The Bell inequality distinguishes between local realism—the 'common sense' view in which Alice's observations do not depend on Bob's, and vice versa—and Physicist Reinhold Bertlmann of the University of quantum mechanics, or, specifically, quantum Vienna, Austria has published a review of the work entanglement. Two quantum particles, such as of his late long-term collaborator John Stewart Bell those in the Alice-Bob situation, are entangled of CERN, Geneva in EPJ H. This review, "Real or when the state measured by one observer Not Real: that is the question," explores Bell's instantaneously influences that of the other. This inequalities and his concepts of reality and theory is the basis of quantum information. explains their relevance to quantum information and its applications. And quantum information is no longer just an abstruse theory. It is finding applications in fields as John Stewart Bell's eponymous theorem and diverse as security protocols, cryptography and inequalities set out, mathematically, the contrast quantum computing. -
Final Copy 2020 11 26 Stylia
This electronic thesis or dissertation has been downloaded from Explore Bristol Research, http://research-information.bristol.ac.uk Author: Stylianou, Nicos Title: On 'Probability' A Case of Down to Earth Humean Propensities General rights Access to the thesis is subject to the Creative Commons Attribution - NonCommercial-No Derivatives 4.0 International Public License. A copy of this may be found at https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode This license sets out your rights and the restrictions that apply to your access to the thesis so it is important you read this before proceeding. Take down policy Some pages of this thesis may have been removed for copyright restrictions prior to having it been deposited in Explore Bristol Research. However, if you have discovered material within the thesis that you consider to be unlawful e.g. breaches of copyright (either yours or that of a third party) or any other law, including but not limited to those relating to patent, trademark, confidentiality, data protection, obscenity, defamation, libel, then please contact [email protected] and include the following information in your message: •Your contact details •Bibliographic details for the item, including a URL •An outline nature of the complaint Your claim will be investigated and, where appropriate, the item in question will be removed from public view as soon as possible. On ‘Probability’ A Case of Down to Earth Humean Propensities By NICOS STYLIANOU Department of Philosophy UNIVERSITY OF BRISTOL A dissertation submitted to the University of Bristol in ac- cordance with the requirements of the degree of DOCTOR OF PHILOSOPHY in the Faculty of Arts. -
Disproof of John Stewart Bell
Disproof of John Stewart Bell T. Liffert 4th October 2020 Abstract The proof of John Stewart Bell [1] [2] is based on wrong premises. A deterministic model for a hidden mechanism with an parameter λ is therefor possible. This model is possible by an integration of the experimental context into the wave function 1 The basic experiment The following considerations are based on an experiment with a pair of en- tangled photons, each of them meets a polarisation filter. The crucial phe- nomenon consists of the fact, that, if the polarisation filters are adjusted identically, the photons react always identically: Either both will be ab- sorbed or both will be transmitted. For the angular difference Φ between the polarisation filter adjustments the probability, that both photons give identi- cal measurement results, is the square of the cosine of that angular difference (law of Malus)[3]. The set of the possible measurement results is a binary one, it can be referred to by expressions like f0; 1g or f+1; −1g. For later considerations of serie experiments and related expected values I use the set f+1; −1g, for the treatment of the proof variant according to Wigner-Bell I choose the set f0; 1g. I use the following assignments for measurement results and eigenstates • 0 j0i ! 1 • 1 j1i ! −1 May α denote the measurement result of the left photon and β the one of the right photon. The upper proposition for the conditional probability P of identical measurement results given the angular difference Φ one would write like this: P (α = βjΦ) = cos2 Φ (1) 1 1.1 The quantum mechanical doctrine In the literature that I know there is a strict separation between the quantum state jΨi of the pair of photons on the one hand and the experimental context, consisting of nothing more than the angular difference of the polarisation filters or the polarizers, on the other hand. -
Steven Weinberg
Obituary Steven Weinberg (1933–2021) Theoretical physicist whose electroweak theory won the Nobel prize. teven Weinberg brought the funda- on to positions at Columbia University, New mental understanding of nature to York; the University of Berkeley, California; new levels of power and completeness. the Massachusetts Institute of Technology in He played a central part in formulating Cambridge; and, in 1973, to Harvard University and establishing theoretical physics’ in Cambridge, where he was Higgins Professor Stwo standard models — the standard model of Physics. In 1982, he moved to the University of fundamental interactions and the standard of Texas at Austin, where he remained, teach- model of cosmology. His greatest achievement ing until earlier this year. was to propose the unified theory of electro- Scientists, no less than composers, have magnetism and weak interactions, which is still styles. Einstein and Richard Feynman were in use. This won him the Nobel Prize in Phys- rebellious, most comfortable when they were ics in 1979, shared with his school classmate ‘thinking different’. Weinberg was not like that. Sheldon Lee Glashow, and with Abdus Salam. His approach was scholarly. Most obviously, he His 1967 Physical Review Letters paper, ‘A was keenly interested in the history of physics in Model of Leptons’, combined disparate ideas the West, about which he wrote several deeply about gauge symmetry, symmetry breaking researched and unashamedly ‘Whiggish’ books, and the classification of particles into an ele- most recently To Explain the World (2015). gant whole. Given the state of knowledge at He paid close attention to other people’s CERN/SPL the time, the breakthrough still calls to mind work. -
Sam Treiman Was Born in Chicago to a First-Generation Immigrant Family
NATIONAL ACADEMY OF SCIENCES SAM BARD TREIMAN 1925–1999 A Biographical Memoir by STEPHEN L. ADLER Any opinions expressed in this memoir are those of the author and do not necessarily reflect the views of the National Academy of Sciences. Biographical Memoirs, VOLUME 80 PUBLISHED 2001 BY THE NATIONAL ACADEMY PRESS WASHINGTON, D.C. Courtesy of Robert P. Matthews SAM BARD TREIMAN May 27, 1925–November 30, 1999 BY STEPHEN L. ADLER AM BARD TREIMAN WAS a major force in particle physics S during the formative period of the current Standard Model, both through his own research and through the training of graduate students. Starting initially in cosmic ray physics, Treiman soon shifted his interests to the new particles being discovered in cosmic ray experiments. He evolved a research style of working closely with experimen- talists, and many of his papers are exemplars of particle phenomenology. By the mid-1950s Treiman had acquired a lifelong interest in the weak interactions. He would preach to his students that “the place to learn about the strong interactions is through the weak and electromagnetic inter- actions; the problem is half as complicated.’’ The history of the subsequent development of the Standard Model showed this philosophy to be prophetic. After the discovery of parity violation in weak interactions, Treiman in collaboration with J. David Jackson and Henry Wyld (1957) worked out the definitive formula for allowed beta decays, taking into account the possible violation of time reversal symmetry, as well as parity. Shortly afterwards Treiman embarked with Marvin Goldberger on a dispersion relations analysis (1958) of pion and nucleon beta decay, a 3 4 BIOGRAPHICAL MEMOIRS major outcome of which was the famed Goldberger-Treiman relation for the charged pion decay amplitude. -
Deconstruction: Standard Model Discoveries
deconstruction: standard model discoveries elementary types of particles form the basis for the theoretical framework known as the Sixteen Standard Model of fundamental particles and forces. J.J. Thomson discovered the electron in 1897, while scientists at Fermilab saw the first direct interaction of a tau neutrino with matter less than 10 years ago. This graphic names the 16 particle types and shows when and where they were discovered. These particles also exist in the form of antimatter particles, with the same mass and the opposite electric charge. Together, they account for about 300 subatomic particles observed in experiments so far. The Standard Model also predicts the Higgs boson, which still eludes experimental detection. Experiments at Fermilab and CERN could see the first signals for this particle in the next couple of years. Other funda- mental particles must exist, too. The Standard Model does not account for dark matter, which appears to make up 83 percent of all matter in the universe. 1968: SLAC 1974: Brookhaven & SLAC 1995: Fermilab 1979: DESY u c t g up quark charm quark top quark gluon 1968: SLAC 1947: Manchester University 1977: Fermilab 1923: Washington University* d s b γ down quark strange quark bottom quark photon 1956: Savannah River Plant 1962: Brookhaven 2000: Fermilab 1983: CERN νe νμ ντ W electron neutrino muon neutrino tau neutrino W boson 1897: Cavendish Laboratory 1937 : Caltech and Harvard 1976: SLAC 1983: CERN e μ τ Z electron muon tau Z boson *Scientists suspected for several hundred years that light consists of particles. Many experiments and theoretical explana- tions have led to the discovery of the photon, which explains both wave and particle properties of light. -
Memories of a Theoretical Physicist
Memories of a Theoretical Physicist Joseph Polchinski Kavli Institute for Theoretical Physics University of California Santa Barbara, CA 93106-4030 USA Foreword: While I was dealing with a brain injury and finding it difficult to work, two friends (Derek Westen, a friend of the KITP, and Steve Shenker, with whom I was recently collaborating), suggested that a new direction might be good. Steve in particular regarded me as a good writer and suggested that I try that. I quickly took to Steve's suggestion. Having only two bodies of knowledge, myself and physics, I decided to write an autobiography about my development as a theoretical physicist. This is not written for any particular audience, but just to give myself a goal. It will probably have too much physics for a nontechnical reader, and too little for a physicist, but perhaps there with be different things for each. Parts may be tedious. But it is somewhat unique, I think, a blow-by-blow history of where I started and where I got to. Probably the target audience is theoretical physicists, especially young ones, who may enjoy comparing my struggles with their own.1 Some dis- claimers: This is based on my own memories, jogged by the arXiv and IN- SPIRE. There will surely be errors and omissions. And note the title: this is about my memories, which will be different for other people. Also, it would not be possible for me to mention all the authors whose work might intersect mine, so this should not be treated as a reference work. -
John S. Bell's Concept of Local Causality
John S. Bell’s concept of local causality Travis Norsena) Department of Physics, Smith College, McConnell Hall, Northampton, Massachusetts 01063 (Received 15 August 2008; accepted 6 August 2011) John Stewart Bell’s famous theorem is widely regarded as one of the most important developments in the foundations of physics. Yet even as we approach the 50th anniversary of Bell’s discovery, its meaning and implications remain controversial. Many workers assert that Bell’s theorem refutes the possibility suggested by Einstein, Podolsky, and Rosen (EPR) of supplementing ordinary quantum theory with “hidden” variables that might restore determinism and/or some notion of an observer- independent reality. But Bell himself interpreted the theorem very differently—as establishing an “essential conflict” between the well-tested empirical predictions of quantum theory and relativistic local causality. Our goal is to make Bell’s own views more widely known and to explain Bell’s little- known formulation of the concept of relativistic local causality on which his theorem rests. We also show precisely how Bell’s formulation of local causality can be used to derive an empirically testable Bell-type inequality and to recapitulate the EPR argument. VC 2011 American Association of Physics Teachers. [DOI: 10.1119/1.3630940] I. INTRODUCTION theory could be rendered compatible with local causality by following Newton and by denying that the theory in question In its most general sense, “local causality” is the idea that provided a complete description of the relevant phenomena. physical influences propagate continuously through space— This changed in 1905 with Einstein’s discovery of special that what Einstein famously called “spooky actions at a dis- relativity, which for the first time identified a class of causal 1 tance” are impossible.