Obituary of Władysław J. Świątecki

The distinguished theoretical physicist Władysław (Wladek) Świątecki passed away at his home in Berkeley, California, last autumn after several months of illness. He was 83 years old.

Wladek was born on Saturday, April 22, 1926, in Paris, France, where his father was finishing his studies as an aeronautical engineer. That summer, the family returned to Poland and settled in the city of Lublin. At the age of thirteen, following the invasion that started World War II in September 1939, Wladek and his family managed to escape from Poland and took up residence in Paris. However, the subsequent invasion of France in May 1940 prompted another escape which, by way of Casablanca, Morocco, led the family to relative safety in England, where Wladek then completed his education.

After attending Grammar School in Blackpool, he moved to London where he received Bachelor of Science degrees in Physics (1945) and Mathematics (1946) at the Imperial College. Wladek then studied under Rudolph Peierls at Birmingham University and received his Ph.D. in Physics in 1950 with a thesis entitled “The Surface Energy of Nuclei”, a recurring topic throughout his research career.

Wladek spent his first postdoctoral period at the Institute of Theoretical Physics (now the Niels Bohr Institute) in Copenhagen from September 1950 through August 1953, at that time a leading international center for nuclear theoretical physics. Subsequently, he worked for three years at the Department of Mathematical Physics and the Gustav Werner Institute in Uppsala, from September 1953 through August 1956. Wladek then returned to Denmark for a visiting faculty position at the Institute of Physics, University of Aarhus, from September 1956 until May 1957 when he took up a permanent position at the Radiation Laboratory in Berkeley, California, now the Lawrence Berkeley National Laboratory (LBNL). Although he formally retired in 1991, Wladek remained fully active at LBNL and he was engaged in his work until the end of his life.

Wladek’s scientific work is characterized by a long series of outstanding contributions to nuclear physics which have won worldwide recognition. Working mainly in the field of macroscopic nuclear properties, he has been on the leading edge of studies in fission theory, nuclear mass formulae, superheavy element production, and strongly damped collisions. Alongside these activities, Wladek maintained an interest in the properties of rotating, electrically charged or gravitating fluids, work that proved very helpful to the understanding of nuclei at high angular momentum.

In the field of fission theory, Wladek produced (in the beginning alone, later with others), a landmark series of papers in which a unified approach of unprecedented precision was applied to the elucidation of barrier properties for nuclei throughout the periodic table. His work on super-heavy elements was definitive in establishing the physical reasons for such potential islands of stability beyond the heaviest elements then known.

Probably Wladek’s work in the area of nuclear mass formulae has found the widest application. It was carried out over many years in a close collaboration with one of us (WDM). Wladek was among the first to recognize the important role of shell effects and, in characteristic manner, he proposed a very simple scheme for taking those into account. The Droplet Model developments that he led constitute major advances of the concepts first formulated by Bethe in the thirties. The associated finite-range nuclear Thomas-Fermi model, with shell effects incorporated by means of the so-called macroscopic-microscopic method, has provided the field with a consistent and remarkably accurate tool for calculating diverse nuclear properties, such as bindings, deformations, and fission barriers.

His contributions to the understanding of damped nuclear collisions have shaped many discussions of the associated phenomena. With some of his younger associates, he developed the concept of the nuclear proximity force and showed that the internuclear force can be written as a product of a universal force function related to the surface tension and a geometrical factor characterizing the gap between the two juxtaposed surfaces.

His concept of one-body damping opened up an entirely new way of analyzing the dissipative processes that convert collective nuclear motion into chaotic intrinsic excitation. The characteristic features of nuclear one-body dissipation are its relatively large strength and its relatively weak temperature dependence, both directly reflecting the fermionic nature of the nucleons.

The associated insights into nuclear dynamics led to a practically very useful model for calculating the optimal bombarding energy for fusing two heavy nuclei, a key point being the need for an “extra push” to compensate for the dissipative loss of relative nuclear motion before the fusion configuration is reached. In his later years, Wladek worked closely with the Heavy Element Group in Berkeley, applying his model and insights to the planning and analysis of experiments.

An outgrowth of the work on nuclear dissipation was Wladek’s keen interest in chaos theory, as he sought to illuminate the key role played by symmetries for the character of the nuclear shape dynamics, which changes from resembling that of an elastic solid to that of a drop of honey when the introduction of shape irregularities changes the intrinsic nucleonic motion from ordered to chaotic.

Being situated in Berkeley, it was natural for Wladek to contribute actively to the developments of the fundamental concepts in the field of high-energy nuclear collisions that was emerging with the advent of the Bevalac in the seventies. In particular, he formulated the concepts of “participants” and “spectators” and developed the associated abrasion-ablation model around which much of the subsequent modeling was done. He continued to devote part of his time to the issues of this frontier, such as the conditions for quark-gluon plasma formation.

In addition to his work in areas related to nuclear physics, Wladek had a number of broader physics interests, such as relativity, a main theme being a pedagogical reformulation of the theory without any reference to the speed of light (which, he felt, only confused the key issue). His broad range of interests notwithstanding, Wladek’s major scientific achievements are associated with advancing our understanding of macroscopic nuclear properties, static as well as dynamic. In this he has been the standard bearer for generations and he has served as a mentor for numerous younger colleagues. Wladek trained a number of graduate students who have developed successful research careers of their own.

He spent sabbatical years in both Aarhus and Copenhagen and he was elected a member of the Royal Danish Academy of Sciences and Letters in 1973. He maintained active collaborations with nuclear physicists in his native country, Poland, where he was a member of the Academy of Arts and Sciences. Wladek was awarded the Smoluchowski Medal of the Polish Physical Society and he received an honorary degree from the Jagiellonian University in Crakow in 2000.

Wladek will be remembered not only for his many outstanding scientic contributions and his inspiring participation in any discussion, but also as a warm, kind, and caring person, full of enthusiasm, charm, and humor. He lived a life filled with diverse activities, including chess, tennis, running, and sailing, and he was an excellent and versatile craftsman. Thus, in his younger days, he built a house boat on which he lived a number of years while rebuilding, piece by piece from the keel up, an old sail boat (the Vixen) on which he, his family, friends and colleagues would spend many a delightful afternoon cruising the San Fransisco Bay; later on, he made extensive home renovations singlehandedly. Wladek developed an enthusiasm for running long before the sport became common and his dedication was legendary among his colleagues; for collaborators and visitors alike, the best way to secure an uninterrupted discussion session with him was to join him on his bi-weekly ten-mile run in the hills behind the lab.

He had a profound influence on those of us who were fortunate enough to know him. He is survived by his wife Uta and her two children whom he helped raise, his sister in England and his three children and eight grandchildren who all live in Denmark.