Glashow (Glashow), Sheldon L.( American physicist, Nobel Prize in Physics, 1979)
Comments for Glashow (Glashow), Sheldon L.
Biography Glashow (Glashow), Sheldon L.
genus. December 5, 1932, Mr.
American physicist Sheldon Lee Glashow was born in New York. He was the youngest of three sons of immigrants from Bobruisk Lewis Gluchowska and nee Bella Rubin. Father, is based in New York, a thriving office, repair plumbing, changed his name to Mr. Glashow. studied in high school science in the Bronx. His classmates were Steven Weinberg and Gerald Feinberg, who later became a physicist at Columbia University. G. preserved them for what they piqued his interest in physics.
After obtaining Bachelor of Science from Cornell University in 1954. G. graduate studies at Harvard University, where he graduated in 1959. His dissertation 'Vector meson decays of elementary particles' ( "The Vector Meson in Elementary Particle Decays") was written under the leadership of Julius C. Schwinger, who had a great influence on all subsequent scientific activity T. From 1958 to 1960. G. was a scholar of the University of Copenhagen. He then spent a year as a physics researcher at Caltech, and then taught physics at Stanford University, the University of California at Berkeley. In 1967. G. returned to Harvard, where in 1979. was appointed to the chair of physics named Eugene Higgins. In this position he stays still.
Much of the work of Mr.. is devoted to uniting all the forces observed in nature, scientists at the beginning of XIX believed that in nature there are three different and seemingly independent forces of gravity, electricity and magnetism. Progress in facilitating such a view has been made in the 60-ies. last century Scottish mathematician and physicist James Clerk Maxwell, . which showed, . that electricity and magnetism are different manifestations of the same entity, . now known as Maxwell's electromagnetic field theory possible to explain much of, . that first seemed puzzling (mainly the nature of light), . and predict the existence of radio waves,
. It has become a stimulus to the creation of a more general theory that would encompass all the forces of nature.
In the first three decades of XX century. after the discovery of the atomic nucleus physics learned about the existence of two strong interactions, holds together the protons and neutrons that form atomic nuclei, and weak, leading to the disintegration of the nucleus. For example, the radioactive decay of neutrons with the emission of beta particles (electrons) and neutrinos (the process of contributing to the provision of solar energy) is due to the weak interaction. However, strong, . and weak interactions are different from previously known forces in one important respect gravity and electromagnetism have an unlimited range, . strong interaction is effective only at distances, . not exceed the size of the atomic nucleus, . and weak interaction - for even smaller.,
. Innovative theoretical ideas, for which the GA, Abdus Salam and Weinberg were awarded the Nobel Prize, led to the unification of electromagnetism and the weak interaction
. Like Maxwell unification of electricity and magnetism, electromagnetism and the weak interaction in the theory of Glashow - Salam - Weinberg considered as different aspects of a single 'electroweak' interaction. Attempt by Mr.. in 1960. first attempt at unification of electromagnetism and the weak interaction was based on the notion of so-called gauge symmetry. Similar wording proposed a year later and Salam. In everyday life we call a symmetrical object, if it is indistinguishable from its mirror image. Physicists have introduced many other types of symmetry. For example, the charge symmetry in electromagnetism means that the interaction between two particles does not change if all the negative charges are replaced by positive and, conversely, all the positive negative. Gauge symmetry inherent physical properties or relations that remain invariant under change of scale or reference point for relative measurements. In 1954, Mr.. Chen Ning Yang and Robert L. Mills, who worked at Brookhaven National Laboratory, extended the principle of gauge symmetry in more complex physics of strong interactions. Although their research has not turned into a working theory, they paved the way for all subsequent attempts to describe the fundamental interactions, including GM, Weinberg and Salam.
In a sense effort by Mr.. in 1960, to unite electromagnetism and the weak interaction should be considered a success, as his theory is not only joined the force, but also made them indistinguishable. It predicts the existence of four particles - carriers of interactions. One of them could be identified with the photon quantum of light, which was already known as a carrier of the electromagnetic interaction. The remaining three particles, denoted W +, W and Z, were presumed carriers of the weak interactions of matter. In theory, 1960. four particles were massless. In quantum mechanics the interaction radius is inversely proportional to the mass of the particle-carrier, so the zero mass corresponds to an infinite radius of interaction. Thus, contrary to all experimental data, theory T. Assumed infinite radius of interaction, not only for electromagnetism, but also for the weak interaction.
The proposed G. gauge symmetry has led to yet another unconventional conclusion: when two particles are exchanged between the electromagnetic interaction, . their electrical charges do not change, . as the photon (the carrier of electromagnetic radiation) is not a carrier of electric charge,
. However, all known at that time, the weak interaction is implemented transfer of the unit electric charge, such as a neutron decays (with 0 charges) could give rise to a proton (with charge +1) and electron (with charge -1). The phenomena of this kind could be explained by the exchange of particles, W + and W-with charges equal to +1 and -1, respectively. But the introduction of electrically neutral particles of Z means, . that some weak interactions should take place without the exchange of charge, . as in the electromagnetic interaction prediction of events, . called weak neutral currents, . subsequently became a decisive experimental test of the unified theory.,
. tried to fix the main drawback of his theory of an infinite range of the weak interaction, postulating large masses of particles W +, W-and Z0. However, this strategy was not successful if you include the mass, the theory leads to impossible results, such as the infinite intensity of some weak interactions. Similar problems were encountered two decades earlier, were resolved through a mathematical procedure called renormalization, but in the case of weak interaction renormalization 'not working'. The problem of massive particles W and Z was solved a few years, when Weinberg, Salam and other scientists have used new methods.
. Working independently of each other in 1967 and 1968., Weinberg and Salam have created a unified theory of weak and electromagnetic interactions based on the very same gauge symmetry, which used the G
. Theory Weinberg - Salam also claimed the existence of four-vectors of particles, but to give the masses of the particles W +, W-and Z0 and zero mass photon authors have introduced a new mechanism. The idea of this mechanism called spontaneous symmetry breaking is rooted in solid state physics. Subsequently, the W and Z particles were discovered experimentally by Carlo Rubbia among the products of reactions occurring during collisions of particles accelerated to high energies in the accelerator.
In 1979. G., Salam and Weinberg were awarded the Nobel Prize in Physics "for his contribution to the unified theory of weak and electromagnetic interactions between elementary particles, including the prediction of weak neutral currents'. In his Nobel lecture Mr.. shared his memories of those days, . When Julius Schwinger first prompted him to seek the unification of interactions' in 1956, . When I did my first steps in theoretical physics, . theory of elementary particles resembled a patchwork quilt Electrodynamics, . strong and weak interactions were completely separate disciplines, . teach and learn in complete isolation from each other,
. Coherent theory that would unite all the interactions, did not exist '. And further said 'Since then much has changed ... Now we have a theory, which is an integral work of art has become a patchwork tapestry '.
In addition to works on the weak and electromagnetic interactions T. made an important contribution to the understanding of the strong interaction in the 40's and 50-ies. in experiments on high-energy accelerators opened a lot of short-lived particles associated with the proton and neutron, to 1969. was known more than 100 particles, which are considered equally elementary. Many physicists, this situation does not satisfy. And in 1963. Murray Gell-Mann and the American physicist George Zweig proposed method allows to reduce the number of fundamental particles, necessary for the theory of matter. They expressed the hypothesis and that the proton, neutron, and all known their 'family' can be complex particles consisting of several more fundamental particles that Gell-Mann called quarks. Between themselves, the quarks should be linked to the strong interaction.
In the original version of the theory of Gell-Mann had three types of quarks: i-quarks (from the English. up - top), (d-quarks (from the English. down - bottom) and s-quarks (from the English. strange - strange). A year later, when the quark model was still purely speculative, D. with the physicist James D. Borkenom proposed to introduce a fourth quark c. G. called it the charm quark (charm), because he acted like a magic spell, allowing you to eliminate some of the phenomena predicted by three-quark theory, but in fact unobservable. In 1970. G. with John Iliopoulos and Luciano Maiani put forward an even more powerful arguments in favor of the existence of a charmed quark. Particles containing these quarks, were discovered in 1974. Foresight G. received experimental confirmation.
Becoming a Nobel Prize, Mr.. continues to teach and conduct research at Harvard. He attempted to construct a theory that combines the strong and electroweak interactions. In 1987. G. (with John H. Bahkollom of the Princeton Institute of Fundamental Research) reported lower estimates of the neutrino mass. The new estimates, based on an analysis of a supernova explosion, suggests that the mass of neutrinos is insufficient for the treatment of the universe, as suggested by some scientists.
In 1972. G. married Joan Shirley Alexander; they had three sons and a daughter. G. received the Medal of J. Robert Oppenheimer University of Miami (1977) and George Ledley, Harvard University (1978) and honorary degrees from Yeshiva University and the University of Aiks-Marseille. G. is a member of the American Physical Society. American Academy of Arts and Sciences and National Academy of Sciences