SALAM (Salam), Abdus( Pakistani physicist, Nobel Prize in Physics, 1979)
Comments for SALAM (Salam), Abdus
Biography SALAM (Salam), Abdus
genus. January 29, 1926
Pakistani physicist Abdus Salam was born in the rural town of Jang and his son serving the District Office of Education, Mohammad Hussain and Hussain Hadzhiry. S. studying in Government College, Punjab University in Lahore, which he graduated in 1946. with a bachelor. He then, having achieved a special scholarship, went to St. John's College at Cambridge University in England, where in 1949. received a master's degree with highest honors in mathematics and physics. He remained in Cambridge and in 1952. protects the Cavendish Laboratory doctorate in theoretical physics, dedicated to quantum electrodynamics. Following the publication of the dissertation in the same year, she attracted the attention of the international physics community.
In 1951, Mr.. S. became professor of mathematics at the Government College. Originally, he intended to establish in Pakistan a school of theoretical physicists, but soon realized that he could not successfully engage in theoretical physics, living in such a great distance from the leading research centers in Europe, and in 1954. returned to Cambridge as a lecturer in mathematics. Since 1957, Mr.. S. holds the chair of theoretical physics at Imperial College in London. He is also director of the International Center for Theoretical Physics in Trieste (Italy), founded in 1964. to promote the work of scientists from developing countries.
Since the mid 50-ies. S. tried to construct a unified theory of all forces observed in nature, ie. solve a problem dating back to XIX century. In the 1870's. Scottish mathematician and physicist James Clerk Maxwell built a unified theory of electricity and magnetism, reducing them to a single interaction - the electromagnetic. Subsequently, the physics of trying to construct a theory, . which would encompass not only electromagnetism, . and gravity, . as well as the strong and weak interactions (the strong interaction holds together the protons and neutrons, . forming the nucleus of an atom, the weak interaction pushes them),
. And the strong and weak interactions are substantially different from previously known forces. At that time, as gravity and electromagnetism have unlimited range, strong interaction is effective only at distances not exceeding the size of the atomic nucleus, and the weak interaction, there is an even smaller distances.
. New theoretical ideas for which S, Sheldon L
. Glashow and Steven Weinberg were awarded the Nobel Prize, led to the construction of the theory, uniting electromagnetism and the weak interaction. Like Made by Maxwell unification of electricity and magnetism, theory of Salam - Glashow Weinberg allowed to provide electromagnetic and weak interactions as different aspects of a single 'electroweak' interaction. In the early 60-ies. S. and Glashow independently attempted to unite electromagnetism and the weak interaction, based on the concept, known as gauge symmetry. Under the gauge symmetry is understood properties or relationships that remain unchanged when you change the scale or the origin of the relative measurement. In 1954, Mr.. Chen Ning Yang and Robert L. Mills, working at Brookhaven National Laboratory, unsuccessfully tried to generalize the principle of gauge symmetry to take into account the strong interaction. However, their findings provided the impetus for further work, S., Glashow and Weinberg.
In 1960, Mr.. Glashow put forward a unified theory of electromagnetism and weak interaction, . possible to predict the existence of four particles - carriers of interaction, a photon (a carrier of electromagnetic interaction) and three particles, . later received the name W +, . W-and Z0-particles (carriers of the weak interaction),
. One of the main difficulties in the theory of Glashow stemmed from allegations that all the particles have no mass. According to quantum mechanics, the radius of the force is inversely proportional to the mass of the particle-carrier. Consequently, the zero mass means infinite radius for the electromagnetic and weak interactions. Such a theoretical prediction of the experimental data.
To somehow rectify the situation, Glashow postulated for the W +, W-and Z0-particles of large masses. However, this strategy did not lead to success, because after the inclusion of mass theory has lead to impossible results, such as the prediction of an infinite intensity of some weak interactions. Similar problems, . encountered two decades earlier in the theory of electromagnetic interaction, . were solved using a mathematical procedure, . known as renormalization, . but in the case of the electroweak interaction theory of renormalization is not possible to eliminate the infinite intensity,
. The problem of massive W-and Z-particles has been solved in a few years, when Weinberg, Salam and others have used new methods.
With. and Weinberg, working independently and using the gauge symmetry Sheldon Glashow, published in 1968 and 1967. unified theory of weak and electromagnetic interactions. S. and Weinberg proposed a new mechanism for granting the masses of W +, W-and Z0-particle and leaving massless photons. The main idea of this mechanism - the so-called spontaneous (spontaneous) symmetry breaking - originates in solid state physics. The idea with. explained in the following example. Let us imagine that the round-table dinner a group of people. The table was set so that the front of each seat is a plate and napkin placed on the perimeter of the table, midway between the plates. Table service is symmetrical (right and left of each of the diners on the table on a napkin), but is one of those sitting at the table to take a napkin, as symmetry is violated. If the wipes will take all the diners, then the symmetry can be broken, and can not be broken. Although the choice of both right-and left-hand wipes are equally acceptable, the symmetry is restored only if all sitting at the table will make the same choice (ie. all will choose the napkin right away, or all will choose the napkin to the left of itself). Otherwise, someone sitting at a table left without towels, and somewhere in another place a table cloth will remain unused, ie. there is a clear asymmetry.
With. suggested that the gauge symmetry that relates the electromagnetic and weak interactions is spontaneously broken when the energy level varies considerably. At very high energies, these two interactions are indistinguishable. Under these conditions, the mass of W-and Z-particles do not cause any difficulties since the massive particles can be born from the available energy (the equivalence of mass and energy are proved in the created by Albert Einstein in 1905. special theory of relativity.) But at low energies, W-and Z-particles (and, hence, weak interactions) are rare. Since the physics is limited to terrestrial conditions, relatively low energies, the researchers drew attention to the differences between the electromagnetic and weak interactions. In theory, the Weinberg-Salam mass of W +, W-and Z0-particles do not artificially imposed, but arise naturally from the mechanism of spontaneous symmetry breaking. Estimates of the masses of these particles can be obtained from the theory itself. Each of the two W-particles of about 80 times heavier than the proton, and Z-particle is even harder.
And Weinberg, and C. expected that with the help of a mathematical procedure known as renormalization, they will be able to get the final values for all measurable quantities. Partly because neither Weinberg nor C. unable to confirm their expectations of the calculations, their theory until 1971. attracted little attention. In 1971, Mr.. Danish physicist Gerhard Hooft could significantly advance the method of renormalization, and in collaboration with other theorists to complete the proof of this theory. Two years later, researchers at the Fermi National Accelerator Laboratory near Chicago and at CERN (European Organization for Nuclear Research) near Geneva opened weak neutral currents, . thus confirming the theory, . put forward by S., . Glashow and Weinberg,
. In 1983. own W-and Z-particles were discovered at CERN by Carlo Rubbia and his collaborators.
In 1979. S., Glashow and Weinberg were awarded the Nobel Prize in Physics "for his contribution to the theory of unified weak and electromagnetic interaction between elementary particles, including the prediction of the weak neutral current '. In his Nobel lecture with. expressed hope for a unified theory of all forces, including gravity and the strong interaction. 'Einstein grasped the nature of the gravitational charge - he said - expressing it in terms of the curvature of space - time. Can we understand the nature of other charges - the nature of a single set of charges as a whole - in terms of something equally glubokogoN This, in brief, our dream, . hopes for the implementation of which were substantially supported by confirmation of the predictions of the gauge theory '.,
. Interests with
. not restricted to theoretical physics. From 1955 to 1958. He was a member of the UN, working as a scientific secretary of the Geneva Conference on Peaceful Uses of Atomic Energy. From 1964 to 1975. He was a member of the Advisory Committee on Science and Technology UN, and in 1971 and 1972. was chairman of this committee. In 1981. S. led as chairman of the Advisory Commission on Science, Technology and social processes at UNESCO, from 1972 to 1978. was vice-president of the International Union of Pure and Applied Physics. He was also a member of many committees on education and science in Pakistan, and in 1961. was appointed chief scientific adviser to the Office of the President of Pakistan. In the last post with. stayed until 1974
In addition to the Nobel Prize, C. Maxwell was awarded the medal of the London Physical Society (1961), medals Hughes (1964) and Royal Medals (1978). Royal Society of London, . Guthrie medal of the London Physical Institute (1976), . gold medal Matteuchchi the Italian National Academy of Sciences (1978), . Medals John Torrence Tate of the American Physical Institute (1978), . Gold Medal Lomonosov USSR (1983), . as well as other awards and relationships,
. S. is a member of the Pakistan Academy of Sciences. Royal Society of London, the Royal Swedish Academy of Sciences. Pontifical Academy of Sciences, he is also an honorary or foreign member of the American Academy of Arts and Sciences. Academy of Sciences of the USSR and the U.S. National Academy of Sciences, as well as other scientific societies. He - holds almost thirty honorary degrees, including Punjab, Edinburgh, Bristol. Cambridge University, City College of New York City University and the University of Glasgow.