Professor Tom Kibble was an internationally-renowned theoretical physicist
whose contributions to theoretical physics range from the theory of elementary
particles to modern early-universe cosmology. The unifying theme behind all his
work is the theory of non-abelian gauge theories, the Yang-Mills extension of
electromagnetism. One of Kibble's most important pieces of work in this area
was his study of the symmetry-breaking mechanism whereby the force-carrying
vector particles in the theory can acquire a mass accompanied by the appearance
of a massive scalar boson. This idea, put forward independently by Brout and
Englert, by Higgs and by Guralnik, Hagen and Kibble in 1964, and generalised by
Kibble in 1967, lies at the heart of the Standard Model and all modern unified
theories of fundamental particles. It was vindicated in 2012 by the discovery
of the Higgs boson at CERN. According to Nobel Laureate Steven Weinberg, "Tom
Kibble showed us why light is massless"; this is the fundamental basis of
electromagnetism.