COOPER (Cooper), Leon( The American physicist, Nobel Prize in Physics, 1972)
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Biography COOPER (Cooper), Leon
genus. February 28, 1930
American physicist Leon Cooper was born in New York, the son of Irving Cooper and his wife, Anne, married to Zola. Leon grew up in New York, attended high school in the Bronx, and then entered Columbia University where he majored in physics. He became a bachelor in 1951, Master in 1953. and doctor in 1954. While studying at Columbia University in the fundamental interests of K. lay in the field of quantum field theory, which describes the interaction of particles and fields at the atomic or subatomic level.
Scholarship of the National Science Foundation allowed to. to 1954/55 academic year at the Institute for Basic Research in Princeton (New Jersey), after which he served two years post-doctoral work under the guidance of John Bardeen at the University of Illinois. Bardeen studied superconductivity and other properties of matter at temperatures only a few degrees above absolute zero (273 б╟ C).
. Dutch physicist Heike Kamerlingh Onnes discovered in 1911, . that certain metals when cooled to a temperature, . different from absolute zero to a few degrees, . they completely lose their electrical resistance, . - Phenomenon, . received the name of superconductivity,
. His observations are very puzzled scientists of that time, several decades could not find a full explanation.
. On cooling, nearly all metals increases the conductivity, since the thermal vibrations of atoms give rise to electrical resistance due to scattering of electrons involved in the creation of an electric current
. When cooling a metal amplitude decreases, which improves the conductivity. With decrease of temperature in ordinary metals this improvement is gradual, whereas in the superconductor every electrical resistance disappears at temperatures close to absolute zero. Although the atoms of the metal continues to fluctuate, the current carrying electrons, seems to move without interference.
Approximately 1950 g. conducted studies of superconductivity in metals, . with several isotopes (varieties of elements, . have the same number of protons and electrons and thus the same chemical properties, . but different numbers of neutrons) was found that the critical temperature, . in which the isotope becomes superconducting, . inversely proportional to the atomic mass of isotope,
. Atomic mass changes the properties of a rigid body because it affects the distribution of fluctuations in the crystal structure of this body. This observation led Bardeen to the idea that the property of superconductivity depends on the interaction of electrons with atomic vibrations. Bardeen and his colleagues for several years studying these interactions before in 1956. joined K.
Within a short time to. showed, . that the interaction between electrons and crystal lattice gives rise to bound pairs of electrons during the motion through the crystal of the metal one electron attracts the surrounding positively charged atoms, . causing these small deformation of the crystal lattice,
. This deformation, in turn, creates a short-term concentration of positive charge that attracts a second electron. In this way the two electrons are coupled with each other through the crystal lattice, forming what is known as a Cooper pair.
Based on this discovery, J. Robert Schrieffer, a graduate student University of Illinois, who also worked under the guidance of Bardeen, developed a method of analyzing the movements of a large number of pairs of interacting electrons. Last month, he, Bardeen and K. generalized Schrieffer model, thereby creating a general theory of superconductivity. Named by the BCS theory (the initials of its three founders), she argues that in a superconducting material, a large proportion of free electrons behaves in a consistent manner. In the resulting coherent state electrons move in unison. Below the critical temperature effect of the formation of electron pairs, which provides coordinated movement of electrons is stronger than the thermal vibrations of atoms of metal. Indignation, which declined to a single electron and, consequently, would cause the appearance of electrical resistance, can not do it in a superconductor, not acting on the electrons involved in the superconducting state. This event is unlikely, and therefore paired electrons move coherently without loss of energy. BCS theory is often considered the most important contribution to theoretical physics from the inception of quantum theory.
To. with two colleagues received in 1972. Nobel Prize in Physics "for the creation of the theory of superconductivity, usually called the BCS theory '. In his Nobel lecture to. discussed the microscopic quantum interference effects in the theory of superconductivity. Recognizing the practical importance of his work, he noted that 'theory does not produce the treasures of this world (although it may guide us to achieve them). The theory - more. It is the ordering of experience, giving the experience of meaning, but also gives us the pleasure of pure contemplation. "
From 1957 to 1958. K. worked as an assistant professor at Ohio State University, then served in various professorial positions at Brown University, combining with 1974. this work with co-director duties at Brown neurological center. Many times he gave the development of the theory of the central nervous system. He was particularly interested in how the modification of neurons leads to the organization of a distributed memory. Together with his colleague Charles Elbaumom K. developed a flexible system capable of recognizing handwritten letters and convert them into printed. This system was used by IBM Corporation in 1987
To. and his wife, Kay Ann, nee Allard, have been married since 1969, they have two daughters.
In addition to the Nobel Prize, K. was awarded the Comstock Prize of the National Academy of Sciences USA (1968) and the Medal of Descartes Renц╘ Descartes University (1977). He has honorary degrees from Columbia University, University of Sussex. University of Illinois, Brown University and Ohio State University. He is a member of the American Academy of Arts and Sciences, the American Physical Society, the National Academy of Sciences, the American Philosophical Society and the Federation of American Scientists.