Kalyanapuram Rangachari Parthasarathy received the BA (Hons) (1956) in Mathematics from Madras University, Advanced 3-Year Professional Statisticians' Training Course, and PhD (1962) under the supervision of C Radhakrishna Rao from the Indian Statistical Institute (ISI), Kolkata. He worked at the Steklov Mathematical Institute, USSR Academy of Sciences (1962-63), as Lecturer, ISI, University of Sheffield (1964-68), Professor of Statistics, University of Manchester (1968-70) as Professor, University of Bombay and Senior Professor, IIT Delhi (1970-76) and Indian Statistical Institute Delhi Centre (1977-96) where he was also CV Raman Professor of INSA (1996-2001).
Academic and Research Achievements: Parthasarathy's notable finding, in collaboration with R Ranga Rao and SR Srinivasa Varadhan, relate to developing a theory of convolution semigroups of probability measures on topological groups which led ultimately to the publication of his citation classic entitled Probability Measures on Metric Spaces (Academic Press, New York, 1967), reprinted by the American Mathematical Society in 2005. During his stay in the UK, his interests shifted to the mathematical foundations of quantum mechanics. In collaboration with Schmidt and Hudson, he developed a theory of continuous tensor products of Hilbert spaces which ultimately resulted in the discovery of a quantum Ito's formula and a noncommutative stochastic calculus in 1984. His latest interests involve the areas of quantum computation and quantum information.
Other Contributions: At the Delhi Cente of the Indian Statistical Institute, Parthasarathy ran a regular seminar on Quantum Probability which resulted in several publications by the participants. One of the main outcomes of this seminar was the monograph An Introduction to Quantum Stochastic Calculus (Birkhauser Verlag, Basel 1992). He was also Member of the INSA Council (1983-85). He was on the Editorial boards of several journals, including Sankhya, Indian Journal of Pure and Applied Mathematics and Reviews of Mathematical Physics.
Awards and Honours: Professor Parthasarathy was conferred many awards, notably Bhatnagar Prize, TWAS Prize, Mahalanobis Medal by the Indian Science Congress,Honorary DTech by Nottingham Trent University and Honorary Doctorate by Chennai Mathematical Institute. He was elected Fellow of the Indian Academy of Sciences, Bangalore (1974), National Academy of Sciences (India), Allahabad (1990), and Academy of Sciences for the Developing World (TWAS).