Robert Paul Behringer
It is with great sadness that we report the unexpected passing of James B. Duke Professor of Physics Robert Paul Behringer (26 October 1948–10 July 2018) following complications from a surgical procedure. At the time of his death, Bob was an active and highly respected experimental physicist in the areas of fluid dynamics and soft condensed matter physics, a leader in the American Physical Society, a caring and successful mentor of young scientists, and a devoted husband, father, and grandfather. He also made highly valued contributions to Duke University, where he obtained his undergraduate and graduate degrees and held a faculty position for 36 years.
Bob earned his PhD in 1975 under the guidance of Duke Professor Horst Meyer, working on critical phenomena in 3He and 3He–4He mixtures. He then went to Bell Laboratories as a postdoc, where he worked with Guenter Ahlers on heat transport and the onset of Rayleigh–Bénard convection in cryogenic liquid helium. At that time, there was great interest in discovering general principles governing the properties of sustained nonequilibrium systems, and Bob and Guenter published several seminal papers concerning the onset of irregular dynamics in fluids, including the first definitive evidence that deterministic chaos could occur in a fluid. After spending four years as an assistant professor at Wesleyan University in Middletown, Connecticut, Bob moved back to Duke and continued his studies of transport and fluid flow in liquid helium.
In the late 1980s, Bob became interested in techniques for observing the internal dynamics of flows in porous media and in sand. Physicists were particularly excited about the possibility of explaining the generic emergence of power-law scaling in nonequilibrium systems, which promised insights into a diverse array of systems previously studied primarily by engineers and geophysicists. Bob saw the opportunity to perform experiments that could reveal the intricate structures of stresses and flows in granular materials at the grain scale, which opened entirely new perspectives in this field. His observations had a dramatic impact on our understanding of the rheology of granular systems and on the broader topic now known as “jamming.” Most recently, his group discovered the phenomenon of jamming induced by shearing in systems with densities below the critical value for random packings. Bob’s images of force chains in 2D packings of plastic disks have become icons of the science of granular materials and of the emergence of complex structures in nonequilibrium systems. These images have captured the imagination of children and adults at science museums in Durham, Chicago, and San Francisco, as well as of physicists around the world.
Bob was an APS Fellow, an AAAS Fellow, and the recipient of the Jesse Beams Award of the Southeastern Section of APS. He made several notable contributions to APS and to the broader scientific and engineering community through his organizational efforts. He was a leader for many years in the organization of Dynamics Days, an annual conference that brings together physicists, mathematicians, engineers, and researchers in a wide variety of other fields to share ideas about nonlinear and complex dynamics. Within APS, he played a founding role in the Group on Statistical and Nonlinear Physics, chairing the group in its third year of existence, and in the Group on the Physics of Climate, chairing that group in its second year. Bob also was a cofounder and editor-in-chief of the journal Granular Matter. At Duke, Bob cofounded Duke’s Center for Nonlinear and Complex Systems, which had a dramatic impact on the university’s support of interdisciplinary science.
Bob was an exceptionally encouraging and nurturing advisor of young scientists. He saw the potential for excellence in an unusually diverse group of advisees and exchange students, and he found ways to help them succeed. He also extended his passion for science to elementary school students with his “magic of science” shows. Outside physics, Bob had many talents that he generously shared with others. He was an accomplished pianist and singer and loved the French language, culture and history.
Bob is survived by his wife of 47 years, two children, four grandchildren, and his brother. He leaves behind a rich legacy of about 260 published articles, 28 PhD students, more than 20 postdoctoral mentees and visitors to his lab, and many students, friends, and colleagues who greatly benefitted from and enjoyed his mentorship, scientific innovation, and scientific leadership. We will miss him greatly.
