John Clive Ward

John Clive Ward, (1 August 1924 – 6 May 2000) was an Anglo-Australian physicist who made significant contributions to quantum field theory, condensed-matter physics, and statistical mechanics. Andrei Sakharov called Ward one of the titans of quantum electrodynamics.

Ward introduced the Ward–Takahashi identity. He was one of the authors of the Standard Model of gauge particle interactions: his contributions were published in a series of papers he co-authored with Abdus Salam. He is also credited with being an early advocate of the use of Feynman diagrams. It has been said that physicists have made use of his principles and developments "often without knowing it, and generally without quoting him." on 1 August 1924. and his wife Winifred Palmer, a schoolteacher. He had a sister, Mary Patricia. He attended Chalkwell Elementary School and Westcliff High School for Boys. In 1938 he sat for and won a £100 scholarship to Bishop Stortford College. He took the Higher School Certificate Examination in 1942, receiving distinctions in Mathematics, Physics, Chemistry and Latin, and was offered a postmastership (scholarship) to Merton College, Oxford.

Although the Second World War was raging at the time, Ward was not called up by the Army, and was allowed to complete his Bachelor of Arts degree in Engineering Science with first class honours, studying mathematics under J. H. C. Whitehead and E. C. Titchmarsh. He received a bursary from the Harmsworth Trust, and in October 1946, with the war over, secured a position as a graduate assistant to Maurice Pryce, who had recently been appointed a professor of theoretical physics at Oxford. He became a fellow of the Royal Society in 1965.

Andrei Sakharov said Ward was one of the "titans" of quantum electrodynamics alongside Freeman Dyson, Richard Feynman, Julian Schwinger, Sin-Itiro Tomonaga and Gian Carlo Wick. In this regard, it has been said that physicists have made use of his principles and developments "often without knowing it, and generally without quoting him." For polarisations x and y, Ward derived this probability amplitude to be:

This can be used to derive the correlation of polarisation of the two photons. This was the first experimental confirmation of a pair of entangled photons as applicable to the Einstein–Podolsky–Rosen (EPR) paradox. The result was subsequently explained by Richard Dalitz and Frank Duarte. Apparently following Dirac's doctrine, Ward was never bothered by issues of interpretation in quantum mechanics.

Ward identity Pryce arranged for Ward to receive an award from the Department of Scientific and Industrial Research (DSIR) for two years. It was then that he developed the Ward–Takahashi identity, originally known as "Ward Identity" (or "Ward's Identities"). This result in quantum electrodynamics was inspired by a conjecture of Freeman Dyson, and was disclosed in a one-half-page letter typical of Ward's succinct style. In their book Quantum Electrodynamics, Walter Greiner and state in their discussion of charge renormalisation: "the Ward Identity has a much more fundamental significance: it ensures the universality of the electromagnetic interaction." In his book The Infinity Puzzle, Frank Close wrote: "Ward's Identities are the basic foundations on which the entire edifice of renormalisation rests."

In 1950, Ward's DSIR fellowship was coming to an end. Pryce had become a visiting professor at the Institute for Advanced Study in Princeton, New Jersey, and Ward's colleagues P. T. Matthews and Abdus Salam were visiting members there in the 1950–1951 academic year. Through them, he was able to secure a $3,000 membership for the 1951–1952 academic year. It was at Princeton that he was introduced to the Ising Model, and met Mark Kac from Cornell University, with whom he would collaborate on an exact solution of the Ising model using a combinatorial method. His joint work with Kac on the Ising Model gave rise to what is now being called the Kac-Ward operator. When his membership ended he worked for the Bell Laboratories in 1952 and 1953. Ward wrote a note to Abdus, informing him that Albert Einstein would be spinning in his grave, presumably clockwise. Ward also made contributions to quantum mechanics, fermion theory, quantum solid-state physics, and statistical mechanics and the Ising model.

Aldermaston In 1955, Ward was recruited by William Cook to work on the British hydrogen bomb programme at the Atomic Weapons Research Establishment at Aldermaston. The British government had decided that it needed hydrogen bombs, and it was Aldermaston's task to design one. John Corner recalled that Ward did not fit in at Aldermaston. and the development of a more advanced design than the Americans had would be the key to achieving the overall objective of the project—a resumption of the nuclear Special Relationship with the Americans. He has been called the "father of the British H-bomb". He is credited with being an early pioneer in the use of Feynman diagrams, and spreading their use in Australia. In the late 1970s Ward participated, with Frank Duarte, in the successful Macquarie science reform movement, and considered this a "most important accomplishment". The most visible sign was that the university agreed to present Bachelor of Science (BSc) degrees instead of just Bachelor of Arts (BA) degrees, the former being more highly prized by students and workplaces in Australia.

Personal life and death Besides his physics, Ward played the piano and the French horn. Ward played the piano at public performances, for example, in August 1968 playing Grieg at Blacktown Town Hall, Sydney. He was a bachelor for most of his life, but he was briefly married while in the US. He had no children. He died on Vancouver Island in British Columbia, Canada, on 6 May 2000, from a respiratory illness.