Kernphysiker in einer neuen Welt: Die Emigranten der dreißiger Jahre in Amerika. - Unter der großen Anzahl derjenigen, die durch Nationalsozialismus zur Emigration gezwungen wurden und zwischen 1933 und 1941 in die Vereinigten Staaten von Amerika einwanderten, befanden sich auch mehr als hundert Physiker, und unter ihnen einige der genialsten Kernphysiker der Welt. Die Physik in Amerika hatte damals den Status einer voll ausgereiften Wissenschaft erreicht, und so kam es zu einem bedeutsamen und facettenreichen Zusammenwirken zwischen den emigrierten und den (...) einheimischen Kernphysikern, zumal sie die verschiedenen Forschungsgebiete vertraten, die sich durch die Entdeckungen und Erfindungen des Jahres 1932 (Neutron, Deuterium, Positron, Cockcroft-Walton-Beschleuniger, Zyklotron) aufgetan hatten. Von besonderer Bedeutung Für die Konsolidierung und Entwicklung der gesamten Kernphysik war dabei die Veröffentlichung von drei Artikeln in den Reviews of Modern Physics von 1936 und 1937, bekannt als die „Bethe-Bibel”︁. Nach der Entdeckung der Kernspaltung von 1938 und dem Ausbruch des Krieges 1939 in Europa wirkte die Befürchtung, daß Hitler eine Atomwaffe erhalten könnte, als mächtige, Emigranten und Nicht-Emigranten gleichermaßen erfassende einigende Kraft unter den Atomphysikern in Amerika, und die meisten von ihnen stellten ihre Fähigkeiten in den Dienst der US-Regierung und arbeiteten am Manhatten-Projekt und an anderen militärischen Forschungsvorhaben mit. Bei Kriegsende waren die in den dreißiger Jahren emigrierten Kernphysiker wie so viele Flüchtlinge vor ihnen Amerikaner geworden, und keiner von ihnen kehrte in sein Geburtsland zurück.Among the large number of refugees from Nazism and Fascism entering the United States between 1933 and 1941 were more than 100 physicists, including some of the most gifted nuclear physicists in the world. By that time physics in America had come of age, and a remarkable and multifaceted symbiosis occurred between the émigré and native-born nuclear physicists as they pursued the many avenues of research opened up by the discoveries and inventions of 1932 (neutron, deuterium, positron, Cockcroft-Walton accelerator, cyclotron). Of particular importance for the consolidation and development of the entire field of nuclear physics was the publication in 1936–37 of the three articles in the Revieus of Modern Physics known as the „Bethe Bible”︁. With the discovery of nuclear fission in 1938 and the outbreak of war in Europe in 1939, the fear that a nuclear weapon might fall into Hitler's hands served as a powerful unifying force among nuclear physicists in Amerika, émigrés and non-émigrés alike, and most placed their talents in the service of the United States Government working on the Manhattan Project and other wartime research. By the end of the war, like so many refugees before them, the émigré nuclear physicists of the 1930s had become Americans, and not one of them returned to the country of his birth. (shrink)

This title provides an overview of the atomic nucleus and the theories that seek to explain it. Bringing together a systematic explanation of hadrons, nuclei, and stars for the first time, the author provides the core material needed by students of physics to acquire a solid understanding of nuclear and particle science.

ArgumentThis article describes the efforts of one fifty-year-old nuclear physics research center to stay relevant as the boundaries of nuclear physics have expanded and distributed collaborations have become increasingly common. In adapting to these shifts, SENSE, a university-based institute in the United States, has seen notable changes in power relations, forms of legitimation, and social structures. This article recognizes and investigates these changes through an interpretative investigation of four common media objects incorporated into research practice at (...) the institute: collaboration wikis, telephones, computer simulations, and government reports. In doing so, this article adopts an approach from media studies through which hard-to-see changes in social and cultural life can be investigated by observing media objects in research practice. Ultimately, this article tells the story of a research organization and an entire discipline working to adapt to a rapidly changing scientific landscape. (shrink)

In our paper we propose a philosophicalanalysis, based on the notion ofphenomenological model, of Nuclear Physics. Inthis way, we will show some peculiarities ofthis branch of physics.

A complete theoretical model describing artificial disintegration of nuclei by bombardment with α-particles, developed by Majorana as early as 1930, is discussed in detail jointly with the basic experimental evidences that motivated it. By following the quantum dynamics of a state resulting from the superposition of a discrete state with a continuum one, whose interaction is described by a given potential term, Majorana obtained (among the other predictions) the explicit expression for the integrated cross section of the nuclear process, (...) which is the directly measurable quantity of interest in the experiments. Although this is the first application of the concept of quasi-stationary states to a Nuclear Physics problem, it seems also that the unpublished Majorana work anticipates by several years the related seminal paper by Fano on Atomic Physics. (shrink)

In the centennial of Ettore Majorana’s birth (1906–1938?), we re-examine some aspects of his fundamental scientific production in atomic and molecular physics, including a not well known short communication. There, Majorana critically discusses Fermi’s solution of the celebrated Thomas–Fermi equation for electron screening in atoms and positive ions. We argue that some of Majorana’s seminal contributions in molecular physics already prelude to the idea of exchange interactions (or Heisenberg–Majorana forces) in his later works on theoretical nuclear (...) class='Hi'>physics. In all his papers, he tended to emphasize the symmetries at the basis of a physical problem, as well as the limitations, rather than the advantages, of the approximations of the method employed. (shrink)

Remarkable advances in cold fusion, known also as LENR, raised the hope for a safer and cheaper nuclear energy. The results, however, cannot be explained from the point of view of current physical understanding of nuclear fusion. This is an obstacle for research investment in this field. The present book suggests a new approach for analysis of the experimental results and practical recommendations based on the models of atomic nuclei derived in the BSM-Supergravitation Unified theory (BSM-SG). The book (...) provides: (1) a method for analysis of the LENR experiments using the BSM-SG atomic models; (b) a selection of isotopes suitable for a more efficient energy yield with a minimum of radioactive byproducts; (c) practical considerations for selection of the technical method and the reaction environment. (shrink)

There has been plenty of empirical evidence which shows that the single-particle picture holds to a good approximation in atomic nuclei. In this picture, protons and neutrons move independently inside a mean-field potential generated by an interaction among the nucleons. This leads to the concept of nuclear shells, similar to the electronic shells in atoms. In particular, the magic numbers due to closures of the nucleonic shells, corresponding to noble gases in elements, have been known to play an important (...) role in nuclear physics. Here we propose a periodic table for atomic nuclei, in which the elements are arranged according to the known nucleonic shells. The nuclear periodic table clearly indicates that nuclei in the vicinity of the magic numbers can be understood in terms of a shell closure with one or two additional nucleons or nucleon holes, while nuclei far from the magic numbers are characterized by nuclear deformation. (shrink)

The development of nuclear weapons during the Manhattan Project is one of the most significant scientific events of the twentieth century. This revised and updated 3rd edition explores the challenges that faced the scientists and engineers of the Manhattan Project. It gives a clear introduction to fission weapons at the level of an upper-year undergraduate physics student by examining the details of nuclear reactions, their energy release, analytic and numerical models of the fission process, how critical masses (...) can be estimated, how fissile materials are produced, and what factors complicate bomb design. An extensive list of references and a number of exercises for self-study are included. Links are given to several freely-available spreadsheets which users can use to run many of the calculations for themselves. (shrink)

We provide a detailed history of the concepts of atomic number and isotopy before the discovery of protons and neutrons that draws attention to the role of evolving interplays of multiple aims and criteria in chemical and physical research. Focusing on research by Frederick Soddy and Ernest Rutherford, we show that, in the context of differentiating disciplinary projects, the adoption of a complex and shifting concept of elemental identity and the ordering role of the periodic table led to a relatively (...) coherent notion of atomic number. Subsequent attention to valency, still neglected in the secondary literature, and to nuclear charge led to a decoupling of the concepts of elemental identity and weight and allowed for a coherent concept of isotopy. This concept received motivation from empirical investigations on the decomposition series of radioelements and their unstable chemical identity. A new model of chemical order was the result of an ongoing collaboration between chemical and physical research projects with evolving aims and standards. After key concepts were considered resolved and their territories were clarified, chemistry and physics resumed autonomous projects, yet remained bound by newly accepted explanatory relations. It is an episode of scientific collaboration and partial integration without simple, wholesale gestalt switches or chemical revolutions. (shrink)

The first nuclear engineers emerged from the Manhattan Project in the USA, UK and Canada, but remained hidden behind security for a further decade. Cosseted and cloistered by their governments, they worked to explore applications of atomic energy at a handful of national labs. This unique bottom-up history traces how the identities of these unusually voiceless experts - forming a uniquely state-managed discipline - were shaped in the context of pre-war nuclear physics, wartime industrial management, post-war politics (...) and utopian energy programmes. Even after their eventual emergence at universities and companies, nuclear workers carried the enduring legacy of their origins. Their shared experiences shaped not only their identities, but our collective memories of the late twentieth century. And as illustrated by the Fukushima accident seven decades after the Manhattan project began, this book explains why they are still seen conflictingly as selfless heroes or as mistrusted guardians of a malevolent genie. (shrink)

In 1956, the Swedish Parliament decided to invest in a national nuclear energy program. The decision rested on the conviction that it would be in the interest of the nation to use the assets of natural uranium, the advanced reactor technology, and the expertise on nuclear physics that the country had at its disposal. Since the decision concerned the largest investment ever in Swedish industrial politics, the scientists and engineers had to promise that it would lead to (...) a prosperous future. In this article, the utopian discourse and the rhetoric that were developed to support the Swedish nuclear energy program are analyzed. An important conclusion is that the scientific, technological, political, economic, and moral discourse was not sufficient to create political and civil support. Instead, the scientists and engineers had to turn to the world of myths. Thereby, the conflicts between nuclear physics and magic, scientific objectivity and demons, and rationalistic belief in progress and irrational ideas of faith were dissolved. In Sweden, as in many other Western countries during the 1950s, the world was not disenchanted, but re-enchanted. (shrink)

The influential Berkeley theoretical physicist Geoffrey Chew renounced the reigning approach to the study of subatomic particles in the early 1960s. The standard approach relied on a rigid division between elementary and composite particles. Partly on the basis of his new interpretation of Feynman diagrams, Chew called instead for a “nuclear democracy” that would erase this division, treating all nuclear particles on an equal footing. In developing his rival approach, which came to dominate studies of the strong (...) class='Hi'>nuclear force throughout the 1960s, Chew drew on intellectual resources culled from his own political activities and his attempts to reform how graduate students in physics would be trained. (shrink)

This is one of the most important books on quantum mechanics ever written for lay readers, in which an eminent physicist and successful science writer, Heinz Pagels, discusses and explains the core concepts of physics without resorting to complicated mathematics. "Can be read by anyone. I heartily recommend it!" -- New York Times Book Review. 1982 edition.

Particle physics intertwines theory and experiments, and this text demonstrates and develops the interplay between the two, following the author's detailed and original approach. This complete and comprehensive treatise, written for a two-semester Master's or graduate course, covers all aspects of modern particle physics. Richly illustrated with more than 450 figures, this text guides students through all the intricacies of quantum mechanics and quantum field theory in an intuitive manner that few books achieve. Featuring rigorous step-by-step derivations and (...) more than 100 end-of-chapter problems for additional practice, it ensures that students will not only understand the material but also be able to apply their knowledge. Containing up-to-date experimental material, including the discovery of the Higgs boson at CERN and of neutrino oscillations, this monumental volume also serves as a one-stop reference for particle physics researchers of all levels and specialties. (shrink)

It is proposed to consider present-day physics as dealing with a special situation, the situation in which the phenomena of life and consciousness play no role. It is pointed out that physical theory has often dealt, in the past, with similarly special situations. Planetary theory neglects all but gravitational forces, macroscopic physics neglects fluctuations due to the atomic structure of matter, nuclear physics disregards weak and gravitational interactions. In some of these cases, physicists were well aware (...) of dealing with special situations, or limiting cases as they are called in the article; in other cases, they were not. It is pointed out that, even if it were true that present-day physics accurately describes the motion of the physical constituents of living bodies, it would not give the whole story. Arguments are adduced, however, to show that the laws of physics, applicable for inanimate matter, will have to be modified when dealing with the more general situation in which life and consciousness play significant roles. (shrink)

This paper keeps pace with my personal history as a researcher: starting from the eagerness for knowledge of the nuclear physics PhD student I once was, continuing with my search for social relevance in policy-preparatory research I subsequently performed as a sustainability scholar, it finally leads to the topics of interest for the hybrid philosophy-sociology researcher I am today. Following these traces, I first of all rethink my life as a physicist in terms of science as a necessarily (...) situated and engaged practice before laying bare the baleful scientisation of politics in sustainability discourse. Finally, I sketch the contours of a genuine politics of sustainability by repositioning the enigma of scientific production at the heart of its practice. (shrink)

Th is paper looks at quantum theory and the Standard Model of elementary particles with a view to suggesting a detailed empirical implementation of trope ontology in harmony with our best physics.

We briefly describe in this paper the passage from Mendeleev’s chemistry (1869) to atomic physics (in the 1900’s), nuclear physics (in 1932) and particle physics (from 1953 to 2006). We show how the consideration of symmetries, largely used in physics since the end of the 1920’s, gave rise to a new format of the periodic table in the 1970’s. More specifically, this paper is concerned with the application of the group SO(4,2)⊗SU(2) to the periodic table (...) of chemical elements. It is shown how the Madelung rule of the atomic shell model can be used to set up a periodic table that can be further rationalized via the group SO(4,2)⊗SU(2) and some of its sub-groups. Qualitative results are obtained from this nonstandard table. (shrink)

Using an original approach, Mauro Dardo recounts the major achievements of twentieth-century physics--including relativity, quantum mechanics, atomic and nuclear physics, the invention of the transistor and the laser, superconductivity, binary pulsars, and the Bose-Einstein condensate--as each emerged. His year-by-year chronicle, biographies and revealing personal anecdotes help bring to life the main events since the first Nobel Prize was awarded in 1901. The work of the most famous physicists of the twentieth century--including the Curies, Bohr, Heisenberg, Einstein, Fermi, (...) Feynman, Gell-Mann, Rutherford, and Schrödinger--is presented, often in the words and imagery of the prize-winners themselves. Mauro Dardo is Professor of Experimental Physics at Amedeo Avogadro University. He has served as Dean of the new Faculty of Sciences at the University of Turin in Alessandria, Piedmont, and has also served as Director of the university's new department of Sciences and Advanced Technologies. (shrink)