Dominique Vautherin 1941-2000
Dominique Vautherin passed away last December at the age of 59. His work, characterized by breadth, clarity and originality, profoundly marked the field of nuclear physics. A brilliant nuclear theorist, he had a major influence on the international community during the past 30 years.
Born in 1941, Vautherin studied at the Ecole Polytechnique in 1961-1963. Admitted to the CNRS in 1964, he obtained his doctorate at Paris-Sud in 1969. He spent most of his career at the Division de Physique Theorique of the Institut de Physique Nucleaire at Orsay, where he was director in 1991-1995. A visiting scientist at MIT in 1970-1972 and at the Lawrence Berkeley Laboratory in 1976-1977, he made frequent visits abroad. In 1976-1991 he had teaching responsibilities as Maitre de Conferences at the Ecole Polytechnique. He received the Prix Langevin and the Grand Prix Jean Ricard of the French Physical Society, and had just received an award from the Alexander von Humboldt-Stiftung. From 1999 he was Chairman of the Board of Directors of the European Centre for Theoretical Studies, Trento.
In 1969-1970, together with David Brink, Vautherin recognized the value of Skyrme's interaction for the description of nuclear properties. He soon extended this approach to deformed nuclei and opened the way to a coherent and unified description of all nuclei, light or heavy, spherical or deformed, stable or unstable. It then became possible to reproduce and to predict, solely from Skyrme's interaction and throughout the periodic table, a large number of nuclear properties, such as binding energies, proton and neutron densities, single-particle spectra, equilibrium deformations and (by application of external fields) binding energies as a function of deformation, fission barriers, etc. While at MIT, Vautherin also developed a density matrix expansion that linked Skyrme's interaction with realistic nucleon-nucleon forces.
He extended his approach to dynamical processes and the description of large-amplitude motions. In this way he contributed significantly to the understanding of the relations between individual and collective aspects of nuclear stucture - a recurrent theme of the physics of many-body systems.
His interest in astrophysical problems led him to seminal contributions to the thermodynamics of nuclear matter at high density (neutron stars) and high temperature (supernovae). He made the first calculation of the vaporization temperature of nuclei and studied the influence of the temperature on the nuclear collective excitations.
In recent years he was mainly interested in the properties of the quark-gluon plasma. With his collaborators he elaborated a variational approach, leading to approximate projected solutions of the gauge field equations.
His constant cheerfulness, sense of humour, gentle sarcasm and generosity were proverbial. To all of his French and foreign friends, colleagues and students, it is difficult to imagine that they will no longer benefit from his deep insights and continual enthusiasm.
Marcel Veneroni, IN2P3.
Aleksandr Chudakov 1921-2001
Aleksandr Chudakov, outstanding Russian scientist in the field of cosmic-ray physics, passed away on 25 January at the age of 79.
Chudakov was born on 16 June 1921 and graduated from Moscow State University in 1948. In 1953 he confirmed experimentally the existence of the transition radiation predicted by V L Ginzburg and I M Frank in 1945. In 1955 he predicted the effect of decreasing ionization losses for narrow electron-positron pairs, which was later referred to as the Chudakov effect. Phenomena similar to this effect are now found in quantum chromodynamics.
In the 1950s Chudakov carried out a series of experiments investigating cosmic rays outside the atmosphere with rockets and the first satellites, which resulted in his discovery (in collaboration with S N Vernov) of the Earth's radiation belts during the third Soviet Sputnik flight.
In 1961, with G T Zatsepin, Chudakov suggested the air Cherenkov method for gamma-ray astronomy and carried out a pioneering experiment at Katsively, Crimea.
From the mid-1960s he headed the design and construction of the Baksan underground scintillation telescope (one of the first large multipurpose facilities for underground physics, which was put into operation in 1978). First-class results in astroparticle physics and cosmic rays were obtained with this instrument, which is still in operation.
Aleksandr Chudakov was one of the leaders of cosmic-ray science of his time. Being for some time a chairman of the IUPAP Cosmic Ray Commission, he was known and highly respected by the community all over the world. His death is a great loss to his friends and colleagues.
