2016 Isaac Newton medal of the Institute of Physics

Professor Sir Thomas Kibble, Imperial College London, for developing the theory of symmetry-breaking in quantum field theory, which has led to quantitative models for the origin of the masses of elementary particles, together with experimentally verified applications to soliton formation, and models for structure formation in the early universe.

Picture of Thomas Kibble
Imperial College London

Professor Sir Thomas Kibble was an internationally renowned theoretical physicist whose contributions ranged from the theory of elementary particles to modern early-universe cosmology.

The unifying theme behind all his work is the concept of non-abelian gauge theories. One of Kibble’s most important pieces of work in this area was his study of the Yang-Mills extension of electromagnetism, and, in particular, the mechanism whereby the basic particles in the theory can acquire a mass. What is now known as the Brout-Englert-Higgs-Kibble-Guralnik-Hagen spontaneous symmetry-breaking mechanism lies at the heart of all the modern unified theories of fundamental particles, and was vindicated in 2012 by the discovery of the Higgs boson at CERN. Many believe Kibble to have been unfortunate not to share in the 2012 Nobel Prize awarded to Englert and Higgs, especially in view of his sole-author 1967 paper explaining why the photon remains massless.

The spontaneous symmetry-breaking mechanism also predicts the existence of soliton-like solutions of the field equations. In 1976, Kibble realised that these structures could condense as the universe cooled from the hot conditions prevailing in the big bang, and might therefore have striking effects on the development of large-scale structure in the universe. Kibble’s vision has thereby provided an extraordinary link between the macroscopic and microscopic features of our universe. This effect has been experimentally confirmed in the context of vortex formation in superfluid Helium 3.

Kibble was elected as a fellow of the Royal Society in 1980 and was made an honorary fellow of the IOP in 2012, having been a fellow since 1991. He was a previous winner of the Institute’s Rutherford, and Guthrie medals, the ICTP’s Dirac Prize and the Royal Society’s Hughes medal, and was awarded the Sakurai Prize for Theoretical Physics in 2010 and the Einstein Medal in 2012. He was knighted in 2014 for services to physics.