John Clive Ward

John Clive Ward, FRS (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

In 1947, Ward and Pryce published a paper in Nature, in which they were the first to calculate, and use, probability amplitudes for the polarisation of a pair of quantum entangled photons moving in opposite directions.^[6][7] For polarisations x and y, Ward derived this probability amplitude to be:^[7]

${\displaystyle \left|\psi \right\rangle =(\left|x,y\right\rangle -\left|y,x\right\rangle )}$

which can be normalised as:^[7][8]

${\displaystyle \left|\psi \right\rangle ={1 \over {\sqrt {2}}}(\left|x\right\rangle _{1}\left|y\right\rangle _{2}-\left|y\right\rangle _{1}\left|x\right\rangle _{2})}$

This can be used to derive the correlation of the quantum polarisations of the two photons.

With his Harmsworth scholarship expiring, and seeing few prospects at Oxford, Ward responded to a job advertisement from the University of Sydney. He was offered a position, but when he arrived, found that it was for a tutor, and not a lecturer. He therefore served out the year, then returned to Oxford to complete his Doctor of Philosophy (D.Phil.) thesis on "Some Properties of the Elementary Particles". Ward expected that his thesis, an elaboration of his 1947 paper, would be easily approved by the external examiner, Nicholas Kemmer, but at the last minute Kemmer's place was taken by Rudolf Peierls, who refused to accept it. Only after a forceful argument by the internal examiner, J. de Witt, was the thesis awarded.^[3][12]

Ward identity

Pryce arranged for Ward to receive an award from the

The contributions of Salam and Ward to the Standard Model were used in the development of the theoretical structure of the Higgs boson.^[23] Ward also made contributions to quantum mechanics,^[12][24] fermion theory,^[25] quantum solid-state physics,^[26] and statistical mechanics and the Ising model.^[27]

Aldermaston

In 1955, Ward was recruited by

British knowledge of thermonuclear designs was limited to the work done by the wartime Manhattan Project: Edward Teller's Classic Super,^[3] and a 1946 design by John von Neumann and Klaus Fuchs. All that was known for certain about the American hydrogen bomb design was that it had multiple stages.^[28] "I was assigned", Ward later recalled, "the improbable job of uncovering the secret of the Ulam–Teller invention ... an idea of genius far beyond the talents of the personnel at Aldermaston, a fact well-known to both Cook and Penney."^[29]

After working through a large number of proposals, Ward hit upon a workable design incorporating staging, compression and radiation implosion.^[1][29] At a meeting on 2 December 1955, Ward sketched it on the blackboard. Penny's response was cool, regarding it as too complicated, but Cook recognised it as worthy. Although Ward's design was not the one ultimately adopted for the hydrogen bombs used in Operation Grapple, the concept was influential,^[3][28] 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.^[29][30] He has been called the "father of the British H-bomb".^[2]

Macquarie University

After Maryland, Ward looked for a new job. He thought he had found one at the

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.^[3] He died on Vancouver Island in British Columbia, Canada, on 6 May 2000, from a respiratory illness.^[1]

References