Stig Lundqvist – författare

The theory of the inhomogeneous electron gas had its origin in the Thomas­ Fermi statistical theory, which is discussed in the first chapter of this book. This already leads to significant physical results for the binding energies of atomic ions, though because it leaves out shell structure the results of such a theory cannot reflect the richness of the Periodic Table. Therefore, for a long time, the earlier method proposed by Hartree, in which each electron is assigned its own personal wave function and energy, dominated atomic theory. The extension of the Hartree theory by Fock, to include exchange, had its parallel in the density description when Dirac showed how to incorporate exchange in the Thomas-Fermi theory. Considerably later, in 1951, Slater, in an important paper, showed how a result similar to but not identical with that of Dirac followed as a simplification of the Hartree-Fock method. It was Gombas and other workers who recognized that one could also incorporate electron correlation consistently into the Thomas-Fermi-Dirac theory by using uniform electron gas relations locally, and progress had been made along all these avenues by the 1950s.

This volume is concerned with the theoretical description of patterns and instabilities and their relevance to physics, chemistry, and biology. More specifically, the theme of the work is the theory of nonlinear physical systems with emphasis on the mechanisms leading to the appearance of regular patterns of ordered behavior and chaotic patterns of stochastic behavior. The aim is to present basic concepts and current problems from a variety of points of view. In spite of the emphasis on concepts, some effort has been made to bring together experimental observations and theoretical mechanisms to provide a basic understanding of the aspects of the behavior of nonlinear systems which have a measure of generality. Chaos theory has become a real challenge to physicists with very different interests and also in many other disciplines, of which astronomy, chemistry, medicine, meteorology, economics, and social theory are already embraced at the time of writing. The study of chaos-related phenomena has a truly interdisciplinary charac­ ter and makes use of important concepts and methods from other disciplines. As one important example, for the description of chaotic structures the branch of mathematics called fractal geometry (associated particularly with the name of Mandelbrot) has proved invaluable. For the discussion of the richness of ordered structures which appear, one relies on the theory of pattern recognition. It is relevant to mention that, to date, computer studies have greatly aided the analysis of theoretical models describing chaos.

The theory of the inhomogeneous electron gas had its origin in the Thomas­ Fermi statistical theory, which is discussed in the first chapter of this book. This already leads to significant physical results for the binding energies of atomic ions, though because it leaves out shell structure the results of such a theory cannot reflect the richness of the Periodic Table. Therefore, for a long time, the earlier method proposed by Hartree, in which each electron is assigned its own personal wave function and energy, dominated atomic theory. The extension of the Hartree theory by Fock, to include exchange, had its parallel in the density description when Dirac showed how to incorporate exchange in the Thomas-Fermi theory. Considerably later, in 1951, Slater, in an important paper, showed how a result similar to but not identical with that of Dirac followed as a simplification of the Hartree-Fock method. It was Gombas and other workers who recognized that one could also incorporate electron correlation consistently into the Thomas-Fermi-Dirac theory by using uniform electron gas relations locally, and progress had been made along all these avenues by the 1950s.

This volume is concerned with the theoretical description of patterns and instabilities and their relevance to physics, chemistry, and biology. More specifically, the theme of the work is the theory of nonlinear physical systems with emphasis on the mechanisms leading to the appearance of regular patterns of ordered behavior and chaotic patterns of stochastic behavior. The aim is to present basic concepts and current problems from a variety of points of view. In spite of the emphasis on concepts, some effort has been made to bring together experimental observations and theoretical mechanisms to provide a basic understanding of the aspects of the behavior of nonlinear systems which have a measure of generality. Chaos theory has become a real challenge to physicists with very different interests and also in many other disciplines, of which astronomy, chemistry, medicine, meteorology, economics, and social theory are already embraced at the time of writing. The study of chaos-related phenomena has a truly interdisciplinary charac­ ter and makes use of important concepts and methods from other disciplines. As one important example, for the description of chaotic structures the branch of mathematics called fractal geometry (associated particularly with the name of Mandelbrot) has proved invaluable. For the discussion of the richness of ordered structures which appear, one relies on the theory of pattern recognition. It is relevant to mention that, to date, computer studies have greatly aided the analysis of theoretical models describing chaos.

These volumes are collections of the Nobel Lectures delivered by the prizewinners, together with their biographies, portraits and the presentation speeches for the period 1971 - 1990. Each Nobel Lecture is based on the work that won the laureate his prize. New biographical data of the laureates, since they were awarded the Nobel Prize, are also included. These volumes of inspiring lectures by outstanding physicists should be on the bookshelf of every keen student, teacher and professor of physics as well as those in related fields.Below is a list of the prizewinners during the period 1971-1980 with a description of the works which won them their prizes:(1971) D GABOR — for his invention and development of the holographic method; (1972) J BARDEEN, L N COOPER & J R SCHRIEFFER — for their jointly developed theory of superconductivity, usually called the BCS-theory; (1973) L ESAKI & I GIAEVER — for their experimental discoveries regarding tunneling phenomena in semiconductors and superconductors, respectively; B D JOSEPHSON — for his theoretical predictions of the properties of a supercurrent through a tunnel barrier, in particular those phenomena which are generally known as the Josephson effects; (1974) M RYLE & A HEWISH — for their pioneering research in radio astrophysics: Ryle for his observations and inventions, in particular of the aperture synthesis technique, and Hewish for his decisive role in the discovery of pulsars; (1975) A BOHR, B MOTTELSON & J RAINWATER — for the discovery of the connection between collective motion and particle motion in atomic nuclei and the development of the theory of the structure of the atomic nucleus based on this connection; (1976) B RICHTER & S C C TING — for their pioneering work in the discovery of a heavy elementary particle of a new kind; (1977) P W ANDERSON, N F MOTT & J H VAN VLECK — for their fundamental theoretical investigations of the electronic structure of magnetic and disordered systems; (1978) P L KAPITSA — for his basic inventions and discoveries in the area of low-temperature physics; A A PENZIAS & R W WILSON — for their discoveries of cosmic microwave background radiation; (1979) S L GLASHOW, A SALAM & S WEINBERG — for their contributions to the theory of the unified weak and electromagnetic interaction between elementary particles, including inter alia the prediction of the weak neutral current; (1980) J W CRONIN & V L FITCH — for the discovery of violations of fundamental symmetry principles in the decay of neutral K-mesons.

These volumes are collections of the Nobel Lectures delivered by the prizewinners, together with their biographies, portraits and the presentation speeches for the period 1971 - 1990. Each Nobel Lecture is based on the work that won the laureate his prize. New biographical data of the laureates, since they were awarded the Nobel Prize, are also included. These volumes of inspiring lectures by outstanding physicists should be on the bookshelf of every keen student, teacher and professor of physics as well as those in related fields.Below is a list of the prizewinners during the period 1971-1980 with a description of the works which won them their prizes:(1971) D GABOR — for his invention and development of the holographic method; (1972) J BARDEEN, L N COOPER & J R SCHRIEFFER — for their jointly developed theory of superconductivity, usually called the BCS-theory; (1973) L ESAKI & I GIAEVER — for their experimental discoveries regarding tunneling phenomena in semiconductors and superconductors, respectively; B D JOSEPHSON — for his theoretical predictions of the properties of a supercurrent through a tunnel barrier, in particular those phenomena which are generally known as the Josephson effects; (1974) M RYLE & A HEWISH — for their pioneering research in radio astrophysics: Ryle for his observations and inventions, in particular of the aperture synthesis technique, and Hewish for his decisive role in the discovery of pulsars; (1975) A BOHR, B MOTTELSON & J RAINWATER — for the discovery of the connection between collective motion and particle motion in atomic nuclei and the development of the theory of the structure of the atomic nucleus based on this connection; (1976) B RICHTER & S C C TING — for their pioneering work in the discovery of a heavy elementary particle of a new kind; (1977) P W ANDERSON, N F MOTT & J H VAN VLECK — for their fundamental theoretical investigations of the electronic structure of magnetic and disordered systems; (1978) P L KAPITSA — for his basic inventions and discoveries in the area of low-temperature physics; A A PENZIAS & R W WILSON — for their discoveries of cosmic microwave background radiation; (1979) S L GLASHOW, A SALAM & S WEINBERG — for their contributions to the theory of the unified weak and electromagnetic interaction between elementary particles, including inter alia the prediction of the weak neutral current; (1980) J W CRONIN & V L FITCH — for the discovery of violations of fundamental symmetry principles in the decay of neutral K-mesons.

This is a collection of pedagogical lectures and research papers that were presented during a combined course/conference program held at the International Centre for Theoretical Physics in Trieste in the summer of 1991. The lectures begin from an elementary level and were intended to bring student participants to the point where they could appreciate the research conference that came at the end of program.

This volume contains a set of pedagogical reviews covering the most recent applications of low-dimensional quantum field theory in condensed matter physics, written by experts who have made major contributions to this rapidly developing field of research. The main purpose is to introduce active young researchers to new ideas and new techniques which are not covered by the standard textbooks.