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Vale Dr Graham Derrick



11 February 2011

Graham Derrick did his undergraduate degree at the University of Queensland, and moved from there to the University of Sydney in 1955 to do his MSc. (Qualifying) course, the equivalent of an Honours degree. (At that time, graduates not from the University of Sydney could not do Honours there.)


It is recorded that Graham topped the class that year, and would have been given the University Medal if he had been a Sydney undergraduate. He then went on to do a PhD under the supervision of Professor John Blatt, the topic being "The Ground State of H3". One of the examiners, the famous Professor Herman Feshbach of MIT judged the thesis to be "a definitive work of great merit and importance".


Graham then went on to study for a year at the Institute for Advanced Study, Princeton University, before spending a year at the University of Manitoba as an Assistant Professor in Mathematical Physics. Graham returned to Australia in 1961 to take up a lectureship in the Applied Mathematics Department at the University of New South Wales. Graham was there until 1965, during which time he married his wife, Diana. They raised four children - James, Sarah, Linda and Chris.


From 1965 to 1972, Graham was at the University of St. Andrews, first as Lecturer, then Reader, in Theoretical Physics. He was able to take a year's study leave at the Australian Atomic Energy Commission, Lucas Heights (1970-1971), before becoming Principal Lecturer in Theoretical Physics at the NSW Institute of Technology (now UTS). In 1974, Graham joined the University of Sydney, where he was promoted to Reader in 1976. He took early retirement from the University in July 1990.


Graham was a physicist with a deep and wide knowledge of his subject, who was able to contribute to the advancement of a wide range of fields: field theory, general relativity, elementary particles, statistical mechanics, nuclear physics and solid state physics. One of the things for which he is best known is the Derrick-Hobart Theorem (J. Math. Phys., 5, 1252-1254, 1964), which proves the instability of solutions of a wide class of nonlinear field equations. (This was discovered independently and simultaneously by Dr. R. Hobart.)


Graham was interested both in the most fundamental questions of physics, like rendering the geometry of quantum mechanics compatible with the Minkowski light-cone of special relativity, and the most practical of applications, like the design of the optical security device for the 1988 Bicentennial bank note. (This featured a diffraction grating-based optically variable device, and did not last very long in circulation after it was announced that the OVD was practically indestructible, but even if it was destroyed the note remained legal tender.) Graham attended in succession in 1985 a Symposium on the Foundations of Modern Physics in Joensu Finland, and the International Solar Energy Congress in Montreal Canada.


I doubt there was any other individual attending both these conferences! Graham's work on solar energy commenced when he moved to the University of Sydney. He worked with Dr. Ian Bassett on the very new area of non-imaging optics, as Ian comments: Graham welcomed me when I was a shaky newcomer in the theoretical physics department. Later we collaborated on some work in "non-imaging optics" much of which eventually found its way into an article (whose authors included Walter Welford and Roland Winston) in Emil Wolf's Progress in Optics.


Graham also worked with me on the design of textured surfaces to diminish reflection losses for solar absorbers. The textures had to work well independent of polarization, which meant they had to be doubly periodic rather than singly periodic. This launched us into uncharted waters, so we profited from the opportunity that Graham had to take a sabbatical leave in Marseille, joining up with Daniel Maystre, Patrick Vincent and Michel Neviere to attack a problem which clearly was going to strain the computers of the late 70s.


Graham had the brilliant idea to use a coordinate change in the style of general relativity to flatten the surface by "curving the space" above it. This idea is now at the heart of an emerging field called transformation optics. In an amazing coincidence, when we arrived in Marseille, we found Daniel had a PhD student, Jean Chandezon, who had had precisely the same idea.


Jean developed his form of the transformation method with Daniel for singly periodic gratings. Graham, Daniel, Michel and I developed the method for crossed gratings, with certain differences caused by the need to fit our larger calculations on computers available at the time. The result was a series of papers which were probably twenty years ahead of their time: similar calculations are being carried out today, mainly advanced photovoltaic cells rather than for the photothermal systems we studied.


Graham and his family impressed the researchers in Marseille with their ability to surmount the many difficulties in transplanting a group of six people (two with significant health problems) from an English speaking country to a far-away part of France.


I will end this obituary by quoting Daniel Maystre (with Michel Neviere having expressed very similar sentiments), "Above all, I remember the long stay of Graham and his family in Marseille. They gave us a lesson of courage and showed us that human life is stronger than difficulties. If only for this reason, I will never forget."



Contact: Alison Muir

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