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James Chadwick: Ahead of His Time
July 15, 2020 James Chadwick: ahead of his time Gerhard Ecker University of Vienna, Faculty of Physics Boltzmanngasse 5, A-1090 Wien, Austria Abstract James Chadwick is known for his discovery of the neutron. Many of his earlier findings and ideas in the context of weak and strong nuclear forces are much less known. This biographical sketch attempts to highlight the achievements of a scientist who paved the way for contemporary subatomic physics. arXiv:2007.06926v1 [physics.hist-ph] 14 Jul 2020 1 Early years James Chadwick was born on Oct. 20, 1891 in Bollington, Cheshire in the northwest of England, as the eldest son of John Joseph Chadwick and his wife Anne Mary. His father was a cotton spinner while his mother worked as a domestic servant. In 1895 the parents left Bollington to seek a better life in Manchester. James was left behind in the care of his grandparents, a parallel with his famous predecessor Isaac Newton who also grew up with his grandmother. It might be an interesting topic for sociologists of science to find out whether there is a correlation between children educated by their grandmothers and future scientific geniuses. James attended Bollington Cross School. He was very attached to his grandmother, much less to his parents. Nevertheless, he joined his parents in Manchester around 1902 but found it difficult to adjust to the new environment. The family felt they could not afford to send James to Manchester Grammar School although he had been offered a scholarship. Instead, he attended the less prestigious Central Grammar School where the teaching was actually very good, as Chadwick later emphasised. -
Old Soldiers by Michael Riordan
Old soldiers by Michael Riordan Twenty years ago this month, an this deep inelastic region in excru experiment began at the Stanford ciating detail, the new quark-parton Linear Accelerator Center in Cali picture of a nucleon's innards fornia that would eventually redraw gradually took a firmer and firmer the map of high energy physics. hold upon the particle physics com In October 1967, MIT and SLAC munity. These two massive spec physicists started shaking down trometers were our principal 'eyes' their new 20 GeV spectrometer; into the new realm, by far the best by mid-December they were log ones we had until more powerful ging electron-proton scattering in muon and neutrino beams became the so-called deep inelastic region available at Fermilab and CERN. where the electrons probed deep They were our Geiger and Marsd- inside the protons. The huge ex en, reporting back to Rutherford cess of scattered electrons they the detailed patterns of ricocheting encountered there-about ten times projectiles. Through their magnetic the expected rate-was later inter lenses we 'observed' quarks for preted as evidence for pointlike, the very first time, hard 'pits' inside fractionally charged objects inside hadrons. the proton. These two goliaths stood reso Michael Riordan (above) did The quarks we take for granted lutely at the front as a scientific research using the 8 GeV today were at best 'mathematical' revolution erupted all about them spectrometer at SLAC as an entities in 1967 - if one allowed during the late 1960s and early MIT graduate student during them any true existence at all. -
Hendrik Antoon Lorentz's Struggle with Quantum Theory A. J
Hendrik Antoon Lorentz’s struggle with quantum theory A. J. Kox Archive for History of Exact Sciences ISSN 0003-9519 Volume 67 Number 2 Arch. Hist. Exact Sci. (2013) 67:149-170 DOI 10.1007/s00407-012-0107-8 1 23 Your article is published under the Creative Commons Attribution license which allows users to read, copy, distribute and make derivative works, as long as the author of the original work is cited. You may self- archive this article on your own website, an institutional repository or funder’s repository and make it publicly available immediately. 1 23 Arch. Hist. Exact Sci. (2013) 67:149–170 DOI 10.1007/s00407-012-0107-8 Hendrik Antoon Lorentz’s struggle with quantum theory A. J. Kox Received: 15 June 2012 / Published online: 24 July 2012 © The Author(s) 2012. This article is published with open access at Springerlink.com Abstract A historical overview is given of the contributions of Hendrik Antoon Lorentz in quantum theory. Although especially his early work is valuable, the main importance of Lorentz’s work lies in the conceptual clarifications he provided and in his critique of the foundations of quantum theory. 1 Introduction The Dutch physicist Hendrik Antoon Lorentz (1853–1928) is generally viewed as an icon of classical, nineteenth-century physics—indeed, as one of the last masters of that era. Thus, it may come as a bit of a surprise that he also made important contribu- tions to quantum theory, the quintessential non-classical twentieth-century develop- ment in physics. The importance of Lorentz’s work lies not so much in his concrete contributions to the actual physics—although some of his early work was ground- breaking—but rather in the conceptual clarifications he provided and his critique of the foundations and interpretations of the new ideas. -
Harry Truman, the Atomic Bomb and the Apocalyptic Narrative
Volume 5 | Issue 7 | Article ID 2479 | Jul 12, 2007 The Asia-Pacific Journal | Japan Focus The Decision to Risk the Future: Harry Truman, the Atomic Bomb and the Apocalyptic Narrative Peter J. Kuznick The Decision to Risk the Future: Harry stressed that the future of mankind would be Truman, the Atomic Bomb and theshaped by how such bombs were used and Apocalyptic Narrative subsequently controlled or shared.[3] Truman recalled Stimson “gravely” expressing his Peter J. Kuznick uncertainty about whether the U.S. should ever use the bomb, “because he was afraid it was so I powerful that it could end up destroying the whole world.” Truman admitted that, listening In his personal narrative Atomic Quest, Nobel to Stimson and Groves and reading Groves’s Prize-winning physicist Arthur Holly Compton, accompanying memo, he “felt the same who directed atomic research at the University fear.”[4] of Chicago’s Metallurgical Laboratory during the Second World War, tells of receiving an urgent visit from J. Robert Oppenheimer while vacationing in Michigan during the summer of 1942. Oppenheimer and the brain trust he assembled had just calculated the possibility that an atomic explosion could ignite all the hydrogen in the oceans or the nitrogen in the atmosphere. If such a possibility existed, Compton concluded, “these bombs must never be made.” As Compton said, “Better to accept the slavery of the Nazis than to run a chance of drawing the final curtain on mankind.”[1] Certainly, any reasonable human being could be expected to respond similarly. Three years later, with Hitler dead and the Nazis defeated, President Harry Truman faced Truman and Byrnes en route to Potsdam, July a comparably weighty decision. -
Einstein's Mistakes
Einstein’s Mistakes Einstein was the greatest genius of the Twentieth Century, but his discoveries were blighted with mistakes. The Human Failing of Genius. 1 PART 1 An evaluation of the man Here, Einstein grows up, his thinking evolves, and many quotations from him are listed. Albert Einstein (1879-1955) Einstein at 14 Einstein at 26 Einstein at 42 3 Albert Einstein (1879-1955) Einstein at age 61 (1940) 4 Albert Einstein (1879-1955) Born in Ulm, Swabian region of Southern Germany. From a Jewish merchant family. Had a sister Maja. Family rejected Jewish customs. Did not inherit any mathematical talent. Inherited stubbornness, Inherited a roguish sense of humor, An inclination to mysticism, And a habit of grüblen or protracted, agonizing “brooding” over whatever was on its mind. Leading to the thought experiment. 5 Portrait in 1947 – age 68, and his habit of agonizing brooding over whatever was on its mind. He was in Princeton, NJ, USA. 6 Einstein the mystic •“Everyone who is seriously involved in pursuit of science becomes convinced that a spirit is manifest in the laws of the universe, one that is vastly superior to that of man..” •“When I assess a theory, I ask myself, if I was God, would I have arranged the universe that way?” •His roguish sense of humor was always there. •When asked what will be his reactions to observational evidence against the bending of light predicted by his general theory of relativity, he said: •”Then I would feel sorry for the Good Lord. The theory is correct anyway.” 7 Einstein: Mathematics •More quotations from Einstein: •“How it is possible that mathematics, a product of human thought that is independent of experience, fits so excellently the objects of physical reality?” •Questions asked by many people and Einstein: •“Is God a mathematician?” •His conclusion: •“ The Lord is cunning, but not malicious.” 8 Einstein the Stubborn Mystic “What interests me is whether God had any choice in the creation of the world” Some broadcasters expunged the comment from the soundtrack because they thought it was blasphemous. -
Atomic Physics & Quantum Effects
KEY CONCEPTS ATOMIC PHYSICS & QUANTUM EFFECTS 1. PHOTONS & THE PHOTOELECTRIC EFFECT Max Planck explained blackbody radiation with his quantum hypothesis, which states that the energy of a thermal oscillator, Eosc, is not continuous, but instead is a discrete quantity given by the equation: Eosc = nhf n = 1, 2, 3,... where f is the frequency and h is a constant now known as Planck’s constant. Albert Einstein extended the idea by adding that all emitted radiation is quantized. He suggested that light is composed of discrete quanta, rather than of waves. According to his theory, each particle of light, known as a photon, has an energy E given by: E = hf Einstein’s theory helped him explain a phenomenon known as the photoelectric effect, in which a photon of light strikes a photosensitive material and causes an electron to be ejected from the material. A photocell constructed from photosensitive material can produce an electrical current when light shines on it. The kinetic energy, K, of a photoelectron displaced by a photon of energy, hf, is given by: K = hf - φ where the work function, φ, is the minimum energy needed to free the electron from the photosensitive material. No photoemission occurs if the frequency of the incident light falls below a certain cutoff frequency – or threshold frequency – given by: φ f0 = h Einstein's theory explained several aspects of the photoelectric effect that could not be explained by classical theory: • The kinetic energy of photoelectrons is dependent on the light’s frequency. • No photoemission occurs for light below a certain threshold frequency. -
Wolfgang Pauli Niels Bohr Paul Dirac Max Planck Richard Feynman
Wolfgang Pauli Niels Bohr Paul Dirac Max Planck Richard Feynman Louis de Broglie Norman Ramsey Willis Lamb Otto Stern Werner Heisenberg Walther Gerlach Ernest Rutherford Satyendranath Bose Max Born Erwin Schrödinger Eugene Wigner Arnold Sommerfeld Julian Schwinger David Bohm Enrico Fermi Albert Einstein Where discovery meets practice Center for Integrated Quantum Science and Technology IQ ST in Baden-Württemberg . Introduction “But I do not wish to be forced into abandoning strict These two quotes by Albert Einstein not only express his well more securely, develop new types of computer or construct highly causality without having defended it quite differently known aversion to quantum theory, they also come from two quite accurate measuring equipment. than I have so far. The idea that an electron exposed to a different periods of his life. The first is from a letter dated 19 April Thus quantum theory extends beyond the field of physics into other 1924 to Max Born regarding the latter’s statistical interpretation of areas, e.g. mathematics, engineering, chemistry, and even biology. beam freely chooses the moment and direction in which quantum mechanics. The second is from Einstein’s last lecture as Let us look at a few examples which illustrate this. The field of crypt it wants to move is unbearable to me. If that is the case, part of a series of classes by the American physicist John Archibald ography uses number theory, which constitutes a subdiscipline of then I would rather be a cobbler or a casino employee Wheeler in 1954 at Princeton. pure mathematics. Producing a quantum computer with new types than a physicist.” The realization that, in the quantum world, objects only exist when of gates on the basis of the superposition principle from quantum they are measured – and this is what is behind the moon/mouse mechanics requires the involvement of engineering. -
25 Years of Quantum Hall Effect
S´eminaire Poincar´e2 (2004) 1 – 16 S´eminaire Poincar´e 25 Years of Quantum Hall Effect (QHE) A Personal View on the Discovery, Physics and Applications of this Quantum Effect Klaus von Klitzing Max-Planck-Institut f¨ur Festk¨orperforschung Heisenbergstr. 1 D-70569 Stuttgart Germany 1 Historical Aspects The birthday of the quantum Hall effect (QHE) can be fixed very accurately. It was the night of the 4th to the 5th of February 1980 at around 2 a.m. during an experiment at the High Magnetic Field Laboratory in Grenoble. The research topic included the characterization of the electronic transport of silicon field effect transistors. How can one improve the mobility of these devices? Which scattering processes (surface roughness, interface charges, impurities etc.) dominate the motion of the electrons in the very thin layer of only a few nanometers at the interface between silicon and silicon dioxide? For this research, Dr. Dorda (Siemens AG) and Dr. Pepper (Plessey Company) provided specially designed devices (Hall devices) as shown in Fig.1, which allow direct measurements of the resistivity tensor. Figure 1: Typical silicon MOSFET device used for measurements of the xx- and xy-components of the resistivity tensor. For a fixed source-drain current between the contacts S and D, the potential drops between the probes P − P and H − H are directly proportional to the resistivities ρxx and ρxy. A positive gate voltage increases the carrier density below the gate. For the experiments, low temperatures (typically 4.2 K) were used in order to suppress dis- turbing scattering processes originating from electron-phonon interactions. -
Quantum Mechanics Quantum Chromodynamics (QCD)
Quantum Mechanics_quantum chromodynamics (QCD) In theoretical physics, quantum chromodynamics (QCD) is a theory ofstrong interactions, a fundamental forcedescribing the interactions between quarksand gluons which make up hadrons such as the proton, neutron and pion. QCD is a type of Quantum field theory called a non- abelian gauge theory with symmetry group SU(3). The QCD analog of electric charge is a property called 'color'. Gluons are the force carrier of the theory, like photons are for the electromagnetic force in quantum electrodynamics. The theory is an important part of the Standard Model of Particle physics. A huge body of experimental evidence for QCD has been gathered over the years. QCD enjoys two peculiar properties: Confinement, which means that the force between quarks does not diminish as they are separated. Because of this, when you do split the quark the energy is enough to create another quark thus creating another quark pair; they are forever bound into hadrons such as theproton and the neutron or the pion and kaon. Although analytically unproven, confinement is widely believed to be true because it explains the consistent failure of free quark searches, and it is easy to demonstrate in lattice QCD. Asymptotic freedom, which means that in very high-energy reactions, quarks and gluons interact very weakly creating a quark–gluon plasma. This prediction of QCD was first discovered in the early 1970s by David Politzer and by Frank Wilczek and David Gross. For this work they were awarded the 2004 Nobel Prize in Physics. There is no known phase-transition line separating these two properties; confinement is dominant in low-energy scales but, as energy increases, asymptotic freedom becomes dominant. -
Date: To: September 22, 1 997 Mr Ian Johnston©
22-SEP-1997 16:36 NOBELSTIFTELSEN 4& 8 6603847 SID 01 NOBELSTIFTELSEN The Nobel Foundation TELEFAX Date: September 22, 1 997 To: Mr Ian Johnston© Company: Executive Office of the Secretary-General Fax no: 0091-2129633511 From: The Nobel Foundation Total number of pages: olO MESSAGE DearMrJohnstone, With reference to your fax and to our telephone conversation, I am enclosing the address list of all Nobel Prize laureates. Yours sincerely, Ingr BergstrSm Mailing address: Bos StU S-102 45 Stockholm. Sweden Strat itddrtSMi Suircfatan 14 Teleptelrtts: (-MB S) 663 » 20 Fsuc (*-«>!) «W Jg 47 22-SEP-1997 16:36 NOBELSTIFTELSEN 46 B S603847 SID 02 22-SEP-1997 16:35 NOBELSTIFTELSEN 46 8 6603847 SID 03 Professor Willis E, Lamb Jr Prof. Aleksandre M. Prokhorov Dr. Leo EsaJki 848 North Norris Avenue Russian Academy of Sciences University of Tsukuba TUCSON, AZ 857 19 Leninskii Prospect 14 Tsukuba USA MSOCOWV71 Ibaraki Ru s s I a 305 Japan 59* c>io Dr. Tsung Dao Lee Professor Hans A. Bethe Professor Antony Hewlsh Department of Physics Cornell University Cavendish Laboratory Columbia University ITHACA, NY 14853 University of Cambridge 538 West I20th Street USA CAMBRIDGE CB3 OHE NEW YORK, NY 10027 England USA S96 014 S ' Dr. Chen Ning Yang Professor Murray Gell-Mann ^ Professor Aage Bohr The Institute for Department of Physics Niels Bohr Institutet Theoretical Physics California Institute of Technology Blegdamsvej 17 State University of New York PASADENA, CA91125 DK-2100 KOPENHAMN 0 STONY BROOK, NY 11794 USA D anni ark USA 595 600 613 Professor Owen Chamberlain Professor Louis Neel ' Professor Ben Mottelson 6068 Margarldo Drive Membre de rinstitute Nordita OAKLAND, CA 946 IS 15 Rue Marcel-Allegot Blegdamsvej 17 USA F-92190 MEUDON-BELLEVUE DK-2100 KOPENHAMN 0 Frankrike D an m ar k 599 615 Professor Donald A. -
Particle Detectors Lecture Notes
Lecture Notes Heidelberg, Summer Term 2011 The Physics of Particle Detectors Hans-Christian Schultz-Coulon Kirchhoff-Institut für Physik Introduction Historical Developments Historical Development γ-rays First 1896 Detection of α-, β- and γ-rays 1896 β-rays Image of Becquerel's photographic plate which has been An x-ray picture taken by Wilhelm Röntgen of Albert von fogged by exposure to radiation from a uranium salt. Kölliker's hand at a public lecture on 23 January 1896. Historical Development Rutherford's scattering experiment Microscope + Scintillating ZnS screen Schematic view of Rutherford experiment 1911 Rutherford's original experimental setup Historical Development Detection of cosmic rays [Hess 1912; Nobel prize 1936] ! "# Electrometer Cylinder from Wulf [2 cm diameter] Mirror Strings Microscope Natrium ! !""#$%&'()*+,-)./0)1&$23456/)78096$/'9::9098)1912 $%&!'()*+,-.%!/0&1.)%21331&10!,0%))0!%42%!56784210462!1(,!9624,10462,:177%&!(2;! '()*+,-.%2!<=%4*1;%2%)%:0&67%0%&!;1&>!Victor F. Hess before his 1912 balloon flight in Austria during which he discovered cosmic rays. ?40! @4)*%! ;%&! /0%)),-.&1(8%! A! )1,,%2! ,4-.!;4%!BC;%2!;%,!D)%:0&67%0%&,!(7!;4%! EC2F,1-.,%!;%,!/0&1.)%21331&10,!;&%.%2G!(7!%42%!*H&!;4%!A8)%,(2F!FH2,04F%!I6,40462! %42,0%))%2! J(! :K22%2>! L10&4(7! =4&;! M%&=%2;%0G! (7! ;4%! E(*0! 47! 922%&%2! ;%,! 9624,10462,M6)(7%2!M62!B%(-.04F:%40!*&%4!J(!.1)0%2>! $%&!422%&%G!:)%42%&%!<N)42;%&!;4%20!;%&!O8%&3&H*(2F!;%&!9,6)10462!;%,!P%&C0%,>!'4&;!%&! H8%&! ;4%! BC;%2! F%,%2:0G! ,6! M%&&42F%&0! ,4-.!;1,!1:04M%!9624,10462,M6)(7%2!1(*!;%2! -
Arthur Holly Compton
Arthur Holly Compton ALSO LISTED IN Physicists ALSO KNOWN AS Arthur Holly Compton FAMOUS AS Nobel Prize Laureate in Physics NATIONALITY American Famous American Men RELIGION Baptist BORN ON 10 September 1892 AD Famous 10th September Birthdays ZODIAC SIGN Virgo Virgo Men BORN IN Wooster, Ohio, USA DIED ON 15 March 1962 AD PLACE OF DEATH Berkeley, California, USA FATHER Elias Compton MOTHER Otelia Catherine SIBLINGS Karl Taylor Compton, Wilson Martindale Compton SPOUSE: Betty Charity McCloskey CHILDREN Arthur Allen Compton, John Joseph Compton EDUCATION University of Cambridge, The College of Wooster, Princeton University DISCOVERIES / INVENTIONS Compton Effect AWARDS: Nobel Prize for Physics (1927) Matteucci Medal (1930) Franklin Medal (1940) Hughes Medal (1940) Arthur Holly Compton was a renowned American physicist who first rose to fame with his famous revolutionary discovery of the Compton Effect for which he also won the Nobel Prize in Physics. This discovery confirmed the dual nature of electromagnetic radiation as both a wave and a particle. Thomson was initially interested in astronomy before he shifted his focus to the study of quantum physics. He started his research in Cavendish Laboratory of Cambridge University and this research led to the discovery of Compton Effect. Later on, during the Second World War, Compton became head of the Manhattan Project’s Metallurgical Laboratory. Manhattan Project developed the first nuclear weapons of the world and Compton played a key role in it. He also served as Chancellor of Washington University in St. Louis. Under his leadership, the University made remarkable academic progress; the university formally desegregated its undergraduate divisions, named its first female full professor, and enrolled a record number of students.