Rod Crewther: 23/09/1945 - 17/12/2020


December 27, 2020

Today I learned that Dr Rodney James Crewther, known affectionately by colleagues and students as Rod, died last week. I only knew Rod through my education at the University of Adelaide in the late noughties, where he was a senior lecturer in the Physics department specialising in particle physics, but he had a huge impact on me. My thoughts are with those close to him in this difficult time.

Rod truly cared about educating students. There’s little incentive for university researchers to do anything but the bare minimum for teaching; they gain career advancement through publications and grants. Rod always had time for us students, clearly put a lot of time into his educational material and had an infectious enthusiasm for his subject. My first memory of Rod is from first year Physics, when he taught us about torque by trying to push open a heavy lecture door by pushing with all his strength at the hinge; the slightly silly image has stuck with me as a memorable metaphor for torque.

Rod worked very hard teaching some of the most difficult subjects I studied, making the material clear and well structured. qe designed a lot of the theoretical physics curriculum at Adelaide and taught me Advanced Dynamics and Relativity (the harder parts of classical mechanics and intro to special relativity), Quantum Mechanics, Relativsitic Quantum Mechanics and Particle Physics (RQMPP) and General Relativity. His notes and handouts were always clear and I still have all my notebooks from his courses. These Introductory notes on Quantum Field Theory give an indication of how he taught. I still remember his semi-derivation of the Schrödinger equation by reasoning about wave-particle duality using plane waves and special relativity. Similarly his emphasis on index notation for calculation (and the Levi-Civita identities) has stuck with me, and even today when I’m trying to do multivariable calculus for machine learning I fall back on the familiar index methods Rod taught me.

Rod was a lively character, with a sharp smile, and who was always quick to smile and had a loud laugh. In one of our third year lectures a few of the students talked him into playing the piano before the lecture and I recall he played quite well (I believe a piece by Gershwin, one of his musical idols). He had lots of stories about the people in physics such as his supervisor, Nobel prize winner Murray Gell-Mann, or his sometimes rival Richard Feynman (for example Feynman has a parton model that rivalled Gell-Mann’s quarks; Gell-Mann referred to them as “put-ons”); or about the time he met Dirac. While I didn’t have the pleasure of knowing Rod well as a person, he was always friendly, unpretentious and open.

I don’t know enough physics to understand his work but notably he has publications as late as July 2020. However I’ll quote my friend Lewis Tunstall who did work with him on a paper published in late 2019:

It was indeed great to finish my last paper with Rod. The amazing part of that experience is that we wrote this while he was undergoing several rounds of chemotherapy / surgery to stave off a form of cancer. (He’s better now, thankfully.) Rod taught me a great deal about scientific integrity and working with him was one of the highlights of my time as a physicist.

I’m only one student; Rod taught for 35 years at Adelaide and must have influenced hundreds of students with his passionate teaching. We were extremely lucky to have him there, and his death is a great loss.