Aron Bernstein: In Memoriam (Richard Milner)


I recall first meeting Aron at the Intersections Conference in Rockport, Maine on May 14-19, 1987. He and I collaborated on pioneering experiments to measure spin-dependent electron scattering from polarized He-3 targets. We had two competing target technologies. Aron collaborated with Tim Chupp at Harvard and I was a post-doc with Bob McKeown’s group at Caltech. I moved to MIT in July 1988 and Aron, I and our colleagues successfully carried out the first experiments in subsequent years. The target technologies developed for these Bates experiments are now used in laboratories worldwide and some outstanding young people were involved, e.g., Haiyan Gao who wrote her Caltech Ph.D. thesis on the work.

In the 1990s, Aron and his group played a central role in motivating and realizing the Out Of Plane Spectrometer (OOPS) system at Bates. Costas Papanicolas was a leader of this effort and Bill Bertozzi’s group also made major contributions. Subsequently, when I was Bates Director, we took data on the deformation of the nucleon-delta system using extracted beam from the South Hall Ring. These data strongly constrain the shape of the nucleon.

Aron was an early advocate of the potential of chiral dynamics in understanding nucleon structure. He was influenced by Steven Weinberg’s low energy theorems. Aron initiated the Chiral Dynamics workshop series which continues today – see Ulf Meissner’s talk at last November’s meeting. Aron made important contribution to these pion electroproduction experiments at Mainz and Jefferson Lab.


Aron was very supportive to me when I was a junior faculty member at MIT. He always took time to chat and he was very collegial. An invitation to Susan and Aron’s home for dinner was always warmly welcomed by my wife Eileen and I. They were superb hosts. The food and wine were always of high quality and the guests were always interesting. I remember a first visit to their apartment in Cambridge. There I met fellow-Irishman John Cameron for the first time.

In turn, we always included them in our annual holiday party on Mystic Street and we enjoyed great discussions about the issues of the day long into the evening. If you will indulge me, I would like to also remember Eileen and Bill Turchinetz, and Chris Tschalaer as well as Aron from that annual gathering.

We became good friends. Although we had somewhat different tastes, we had lively discussions of physics. Also, I remember interesting discussions we had comparing Jewish and Irish cultures. He was Jewish, I was Irish, and we each had some distance from these strong cultures but we could see much in common.


Aron was an exemplary citizen in the fullest sense of the word. Most importantly, he took time and effort to make the world a better place. Reduction of nuclear weapons was a particular focus and he initiated, together with Bob Redwine and others, an important program at MIT which frankly has become even more relevant due to the recent terrible events in Eastern Europe. To me, Aron was a model to follow for how he conducted his retirement.


I miss him: particularly the general discussions on physics and important issues of the day. Personally, I miss the social interactions with him. However, he leaves a strong legacy. In physics, he has left chiral dynamics as a healthy area of research. Because of his leadership, the dangers of nuclear weapons are receiving renewed awareness and colleagues at MIT continue his work in this area.