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Death noticeBoris Chirikov
Published on 14 March 2008 Current comments and reminiscences on Boris Chirikov:Boris Chirikov, a pioneer of dynamical chaos, died in Novosibirsk, Russia on 12 February 2008, at the age of 79. His name and ideas are known to everyone working in non-linear dynamics and chaotic behavior of deterministic classical and quantum systems. Boris was born in the central-Russia town Oryol on 6 June 1928. He did his undergraduate and master studies at the Department of Physics and Technology at Moscow University (transformed later to the Moscow Institute of Physics and Technology, MIPT), and continued his experimental studies at the Thermotechnical Laboratory (TTL), which later evolved into the Institute for Theoretical and Experimental Physics (ITEP). After graduating from MIPT in 1952, for a few years Boris was involved in the study of meson physics at the TTL. In 1954 he accepted the offer of Gersh Budker, at that time Head of Laboratory of Novel Acceleration Methods, to join his group at LIPAN (currently the Russian Research Center “Kurchatov Institute”) and to start working on problems of accelerator and plasma physics. In 1958 Budker founded the Institute of Nuclear Physics (INP) in “Akademgorodok” - a brand new scientific center south from Novosibirsk, in West Siberia, and Boris joined him there in September 1959. Since that time and until his last days, Boris worked at the INP (now the Budker Institute of Nuclear Physics), first as an experimentalist, and then evolving into a world class theoretician. He became a corresponding member of the Russian Academy of Sciences in 1983, and a full member in 1992. Boris´s early research at the institute was an experimental study of a few problems formulated by Budker. The first one was related to ionic compensation and stability of a high density relativistic electron beam. After five years of intensive work, Boris with his co-workers built the B-3 betatron with parameters that even now are considered extraordinary. The critical problem in his evolution from experimentalist to theorist was the mysterious loss of electrons in magnetic traps that were suggested by Budker for confinement of hot plasma. A new method of analysis of non-linear resonances developed by Boris in a seminal paper of 1959, led him to understand the new physics responsible for the loss of electrons, the overlap of non-linear resonances resulting in the deterministic diffusion of electrons. This study gave rise to the famous Chirikov “resonance overlap” criterion of chaotic motion in dynamical systems, now used in many applications. Many of the early results of Boris and his coworkers between 1960-1975 were published in the form of preprints and conference proceedings, partly due to a widespread opinion that the dynamical chaos was not a real physical effect, but an artifact of using computers. For this reason, physical journals were reluctant to accept the papers based on numerical results. Only after 1975-1980 was it understood that chaotic motion is one of the basic types of motion in nature, that could conveniently be observed computationally. In 1965 Boris applied his approach to the Fermi-Pasta-Ulam (FPU) paradox and explained it analytically. It was shown that the parameters used in the numerical study of FPU were taken well below the border of strong chaos. Later, these predictions were confirmed numerically. Among other important results of Boris and his group of that period are: the derivation of chaos border in the Fermi-acceleration model (1964), the discovery of weak Arnold diffusion in 4d-nonlinear maps (1969-1975), the analysis of statistical properties of strong chaos in 2d-nonlinear maps (1969), the interplay of non-linearity and dissipation, and an emergence of strange attractors in 2d and 4d dissipative maps (1973-1974), the demonstration that the homogeneous models of classical Yang-Mills field are generally non-integrable (1981), the discovery of the power law decay of Poincaré recurrences in Hamiltonian systems with divided phase space (1981), the demonstration that the dynamics of the Halley comet is chaotic (1989), and many others. Many of these results are summarized in Boris’s professorship thesis in 1969, and in his famous review of 1979 having a few thousand citations. Many of these pioneering studies formed the basis of the work of other scientists around the world. Boris´s work usually included both analytical methods and “numerical experiments”, nowadays considered the most effective method of analysis of complex systems. He used numerical simulations as a new tool of physics, quite often indicating new directions for the theoretical studies as well as suggesting new experiments. Boris´s name is closely associated with the “standard map” that serves as a corner-stone of the theory of dynamical chaos. The role of this map in non-linear physics can be compared with that of the linear oscillator in physics of the past. Many physical systems have mapping approximations whose stability and transition from regular to chaotic motion can be conveniently investigated by expanding around a fixed point to obtain the Chirikov standard map. In 1977 he initiated the investigation of the quantum version of this map, also known as the kicked rotator. The early studies of this model by Boris and his co-workers resulted in a discovery of dynamical localization of quantum chaos. Later, the effect of such localization has been observed in experiments with hydrogen and Rydberg atoms in a monochromatic microwave field, and with cold atoms and Bose-Einstein condensates in optical lattices. In applications to quantum systems with complex behavior, the kicked rotator is considered as the basic model demonstrating all essential properties of quantum chaos. From the first days of the Novosibirsk State University (NSU), Boris actively participated in the development of physics courses. He was one of the initiators of a modern approach to education in physics that was introduced at NSU. His original lectures on classical mechanics and electrodynamics are used by hundreds of students that are working all over the world. His ideas on classical and quantum chaos theory are an essential part both of those who learned directly from him and those who learned from reading his published work. Boris was an extraordinary person. He had a remarkable ability to go deeply into the problems of both theoretical and experimental physics as well as mathematics. To have discussions with Boris was equally helpful and pleasant. His kindness and goodwill is known for all his friends and colleagues. As said by his friend Andy Sessler, many of us can say “I feel touched to have had my life touched by you”. Felix Izrailev, Universidad Autónoma de Puebla and Michigan State University) Allan Lichtenberg, Berkeley, CA Dima Shepelyansky, CNRS, Toulouse |
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