The physics community lost two highly respected figures when Hendrik Casimir and John Ward died within days of each other earlier this month. Both had the distinction of having theories and effects named after them while they were alive.
Hendrik Brugt Gerhard Casimir was born in the Hague in the Netherlands in 1909 and received his PhD from the University of Leiden in 1931. After working with Bohr in Copenhagen and Pauli in Zurich, he joined Philips Research Laboratories in Eindhoven, where he spent the rest of his career. Casimir is best known for his prediction of the Casimir effect in 1948. He predicted that two parallel conducting plates in a vacuum would experience an attractive force due to their influence on the electromagnetic vacuum. The force was detected in experiments 10 years later. Casimir received many honours in his life including an honorary fellowship of the Institute of Physics, fellowship of the Royal Society, and the George E Pake Prize of the American Physical Society. He was also president of the European Physical Society.
John Clive Ward was born in 1924 and educated at Oxford University. After spells at Princeton and Johns Hopkins University in the US, in 1967 he joined Macquarie University in Sydney, Australia, where he spent most of his career. Ward is best known for the “Ward identities” which greatly simplify calculations in quantum field theory and which played an important role in the development of the standard model of particle physics. Ward was elected to the Royal Society in 1965 and received its Hughes Medal in 1983.