Obituary of Hendrik van Dam (1934-2013)

Hendrik van Dam, who made important contributions to field theory, relativity, gravity, particle physics, and group theoretical methods in physics, died of cardiac arrest on February 11, 2013. He was Professor of Physics, and Di- rector of the Institute for Field Physics from 1978 to 1985, at the University of North Carolina (UNC) at Chapel Hill. For many years he co-edited the Journal of Mathematical Physics, with Lawrence Biedenharn, and kept it afloat under difficult conditions, guarding its scientific quality.

Henk, as his friends called him, was born in Zaandam, Holland on May 20, 1934. He did his doctoral work at the University of Amsterdam. In 1961, he accepted an offer from Bryce and Cecile DeWitt to come to UNC as a research associate. He spent the next year in Princeton University as an instructor. Then he returned to Chapel Hill to join the faculty at UNC. He was an Alfred P. Sloan Fellow from 1964 to 1967. Aside from visits to University of Utrecht, University of Nymegen and Instituut Lorentz Leiden in Holland, Henk spent his entire scientific career at UNC until his retirement in May 2005.

Aspiring young physicists probably first come arcoss the name van Dam in the book “Spacetime Physics” by Henk’s friends Edwin Taylor and John Wheeler. In a problem under the heading “Down with relativity,” Taylor and Wheeler wrote, “Mr. van Dam is an intelligent and reasonable man with a knowledge of high school physics.” Of course the real Mr. van Dam was considerably more knowledgeable and resourceful; he worked with Wheeler and clarified the twin paradox for generations of students. With L.P. Staunton, he introduced an ingenious graphical approach to special relativity.

Henk must also have impressed another Princeton physics giant. As the story goes, when Eugene Wigner went to Leiden to give a talk, he invited Henk, then only a graduate student, to have lunch with him. This was the beginning of a collaboration which lasted many years. With Wigner, Henk taught all of us the distinction between active and passive symmetry operations.

Henk had a very productive collaboration with Biedenharn in nearby Duke University. They developed the method of Galilean subdynamics for the con- struction of dual resonance models, expounded on the kinematics of a Poincare-covariant object having indecomposable internal structure, and proposed the concept of a kinematical stability group in impl ementing relativistic symmetry. They also edited a book on the quantum theory of angular momentum.

With Walter Troost, Henk derived thermal propagators in accelerated reference frames and showed how they are related to propagation in a multiply- connected space. With F.A. Berends and G.J.H. Burgers, Henk explicated the theoretical problems in constructing interactions involving high-spin mass particles. He co-organized the third Workshop on Grand Unification with Paul Frampton and Sheldon Glashow and co-edited the Proceedings.

One of Henk’s most influential work was done in collaboration with Martinus Veltman on the so-called van Dam-Veltman-Zakharov discontinuity theorem, using Julian Schwinger’s source theory approach. In his Nobel lecture, Veltman wrote, “H. van Dam and I found the limit from massive gravitons to zero mass is not the same as the massless theory (of Einstein). Thus a theory of gravitation with a massive spin 2 particle of exceedingly small mass would give a result for the bending of light by the sun that was distinctly different (by a factor of 3/4) from that of the massless theory.”

In his latter years, Henk worked closely with one of us (Ng). With J.J. van der Bij, they proposed the unimodular theory of gravity with a constrained determinant of the metric, from the little group viewpoint. This led to a theory equivalent to general relativity, in which the cosmological constant appears as an integration constant. In another collaboration with Ng, Henk investigated limitations to quantum measurements of spacetime distances, with the Wigner-Salecker thought experiment as their starting point. This work led to interesting quantum gravity phenomenology. Later, with Wayne Christiansen, they proposed using extra-galactic sources, such as distant quasars, to probe the minute spacetime fluctuations.

As a person, Henk was warm and kind, forthright and sincere. But if his talk was sometimes too blunt, it was because he thought it his duty to speak the truth plainly and directly. Voltaire said: If God did not exist, it would be necessary to invent him. Many of us will agree to the paraphrase: If Henk did not exist, it would be necessary to invent him, because every institution benefits from having a gadfly in its midst. According to Webster, a gadfly is a purposely provoking person, one who stimulates or provokes to activity, and to the analysis and defense of ideas by persistent criticism. And, as Ludovico Ariosto said in 1532: Nature made him, and then broke the mold. One more quotation from our arduous research: Niels Bohr used to say that to make significant contributions to physics, you have to have a good nose. We submit that Henk was endowed with a terrifically good nose. He sniffed out good problems, he picked good collaborators, and he smelt a rat a mile away.

With the passing of Hendrik van Dam, the physics society has lost a valuable member–one with incredible intuition and insight and deep understanding of physics. And the select few, fortunate enough to have been his collaborators, will always treasure the memory of the joy working with him. They will never forget his contagious enthusiasm and the smiles on his face while he talked physics at the blackboard with them.