John Hubbard (physicist)
John Hubbard | |
|---|---|
| Born | Template:Birth date London, England |
| Died | November 27, 1980 (aged 49) San Jose, California, USA |
| Occupation | Physicist |
| Known for | Hubbard model, Hubbard–Stratonovich transformation |
John Hubbard (27 October 1931 – 27 November 1980) was a British physicist who specialized in solid-state and condensed matter physics. He is best known for developing the Hubbard model of electron interactions and the Hubbard-Stratonovich transformation, both of which have found extensive applications beyond their initial scope.
Early life and education
John Hubbard was born to Charles and Marion Hubbard and grew up in Teddington, London, residing with his parents while attending university. His early education took place at Hampton Grammar School before he proceeded to Imperial College London. There, he completed a Bachelor of Science degree in 1955 followed by a PhD in 1958 under the supervision of Stanley Raimes within the Department of Mathematics. His doctoral research concentrated on the “dielectric approach” to electron Coulomb interactions in metallic systems.
Shortly after earning his doctorate, Hubbard joined the Atomic Energy Research Establishment located at Harwell, having been recruited by Brian Flowers, who was then leading the Theoretical Physics Division.
Harwell
During his initial period at Harwell, Hubbard produced three papers investigating electron correlations in an electron gas through diagrammatic perturbation theory. Although initially hesitant to publish—believing the issue had already been addressed—he was convinced otherwise by Brian Flowers. Later, J.R. Schrieffer described this work as a “classic piece.”
Hubbard eventually became head of the Solid State Theory Group, where his research centered on the electronic and magnetic properties of metals. His group also made practical advances related to gaseous plasmas and isotope separation. By analyzing neutron scattering data from Harwell’s nuclear reactors, Hubbard interpreted transition metal behavior using the Heisenberg model, attributing electron localization effects to correlation phenomena. In 1963, he proposed a simplified model encapsulating these concepts, now widely known as the Hubbard model, which was published independently alongside similar contributions by Martin Gutzwiller and Junjiro Kanamori.
Over the subsequent four years, Hubbard extended this model through five additional papers that explored phenomena such as the transition between a Mott insulator and a conducting state. This work was acknowledged by Walter Kohn as fundamental for understanding electronic structures in magnetic metals and insulators. The methodologies he developed have had a lasting impact on condensed matter physics.
Beginning in 1967, Hubbard broadened his research interests while continuing to delve deeply into established subjects. He authored five papers on approximate methods for calculating band structure and, during the early 1970s, investigated critical phenomena, building upon the pioneering work of Ken Wilson.
Throughout his career at Harwell, Hubbard also held visiting appointments at various American institutions, including a sabbatical year at the Berkeley campus from 1958 to 1959, two summer visits to Brookhaven, and one semester at Brown University. At Berkeley, he helped popularize what is now termed the Hubbard–Stratonovich transformation, a technique that facilitates the evaluation of partition functions in many-body systems.
IBM
During the late 1960s, as interest in nuclear power research waned, Harwell underwent a strategic shift under the leadership of Walter Marshall, moving its focus from atomic science toward contract-based research serving British industry. This change led to alterations in staff composition. Amidst this evolution, Hubbard departed Harwell in 1976 to join the IBM Research Laboratory located in San Jose, California. While at IBM, he made a significant advancement in 1978 by formulating a first-principles theoretical framework addressing the magnetism of iron and other metallic ferromagnets, resolving a complex problem that had its roots in his 1963 Hubbard model.
In addition to theoretical work, Hubbard engaged in practical research endeavors at IBM, exploring areas such as phase conjugate optics and the transitions between neutral and ionic phases.
Personal life
Hubbard met his future wife Joan at Harwell; they wed in August 1958 and had three children: Charles (born 1961), Catherine (born 1964), and Margaret (born 1967). He passed away following a brief illness on in San Jose, leaving behind his family. His colleagues remembered him as reserved, detail-oriented, and a dependable collaborator.
External links
- Biography by A. L. Kuzemsky, 2006
- John Hubbard 1931–1980 by David Thouless, 18 June 2013