Geoffrey V. ChesterMarch 11, 1928 — June 27, 2014
Geoffrey V. Chester died June 27, 2014 in Ithaca, New York, after a brief illness. He was Professor Emeritus of Physics at Cornell University, where he served as Director of the Laboratory of Atomic and Solid State Physics from 1968 to 1974, Associate Dean of Cornell's College of Arts and Sciences from 1978 to 1986, and Dean from 1986 to 1991. He retired in 1995, but maintained a lively and insightful interest in all aspects of physics and life right up to his final week.
Born in Totley, Derbyshire, England in 1928, he was six years old when his family moved to Edinburgh, Scotland. There he attended Daniel Stewart's College and graduated in 1950 from Edinburgh University, where he studied with and admired Max Born. When people referred to Geoffrey as English, as they often did, he would correct them: "Scottish."
He received his PhD in physics in 1954 from Kings College, London. In his thesis he acknowledges C. A. Coulson and H. C. Longuet-Higgins. He then came to the United States for postdoctoral work with Lars Onsager at Yale University and with Joseph Mayer at the University of Chicago. From 1957 to 1964 he was a member of Rudolph Peierls' renowned Department of Mathematical Physics at the University of Birmingham, England. In 1964 he joined the faculty at Cornell, where he played a major role in the construction and leadership of the Cornell condensed-matter theory group, which for over two decades attracted extraordinary graduate students, postdoctoral fellows, and faculty visitors from all over the world.
In low temperature physics Geoffrey Chester has long been known for two theoretical predictions. In 1955 he was among the first to calculate that "we should expect a phase separation of the isotopes" in mixtures of liquid helium-3 and helium-4. A strictly quantum effect, the phase separation was observed the following year and is now exploited in commercially available dilution refrigerators to reach milli-kelvin temperatures. And in 1970 he discovered a plausible ground state for helium-4 that had both crystalline ordering and the off-diagonal long-range order characteristic of Bose-Einstein condensation. This work launched the theoretical and experimental study of supersolids, an endeavor that remains active and controversial to this day.
Following Richard Hammings injunction that "The aim of computation is insight, not numbers," Geoffrey was one of the first physicists to use extensive computation as a crucial component of rigorous theoretical analysis. This work began in the late 1970s, with postdocs and graduate students at both Cornell and the Courant Institute at New York University. He and his collaborators developed and exploited significant advances in quantum Monte Carlo, finding a method for calculating directly from the Hamiltonian the properties of a Bose fluid with all errors small and controlled, leading to essentially exact equations of state for liquid and solid helium-4. They also developed variational Monte Carlo for fermion systems, along with the necessary efficient manipulations of determinants. Their numerical results for Bethe's "Homework Problems" in models of neutron and nuclear matter were widely influential.
Instrumental in these successes were Geoffrey's love of physics, his integrity, and his warm encouragement of young people. His special gift was being able to picture the quantum mechanical phenomena before starting any calculations. His profound phenomenological intuition was the key to the success of his theoretical constructions. He knew the right questions to ask about the most interesting systems.
His expertise in computational physics led him as Associate Dean, several years before the advent of personal computers and text-editing programs, to introduce computers to humanists as surprisingly valuable aides in preparing manuscripts.
Geoffrey was a long-time assistant to, and collaborator with his wife, the ceramist Carolyn Chester. He built many of the wooden structures and frames for her ceramic sculptures, and introduced her to chemicals not ordinarily used in ceramics.
His family, friends, colleagues, and neighbors remember him as a modest, kind, and deeply ethical person, who possessed a ready and playful sense of humor and a tremendous curiosity about almost everything he came across. He had many interests and pursuits and enjoyed talking with anyone who shared them: bread-baking, wood-working, art book collecting. He loved the western islands and highlands of Scotland, and delighted in the wild turkeys that paraded across the family's backyard in upstate New York.
Geoffrey is survived by his wife, Carolyn; his children, Michael, Nicholas, and Sarah; and by his sister and brother-in-law, Dorothy and Gerald Grainger of Dunkeld, Scotland. He will be very much missed by them as well as by his friends, neighbors, and colleagues from his rich academic life.
Neil W. Ashcroft, Malvin H. Kalos, and N. David Mermin
Arts and Sciences Dean Emeritus Geoffrey Chester dies