August 18, 2025
R. Rajaraman, a distinguished Indian theoretical physicist, prominent nuclear weapon policy scholar and advocate for nuclear disarmament, and longtime collaborator with Princeton’s Program on Science and Global Security, died in New Delhi on July 12, after a long illness. He was 86 years old.
Born in British India in March 1939, in Coimbatore, now part of Tamil Nadu state, and the oldest of six boys in the family, Rajaraman was educated at the prestigious St. Stephens College in Delhi, India, receiving his undergraduate degree in 1958 and completing his physics doctorate at Cornell University in 1963. His thesis advisor was Nobel laureate Hans Bethe, who had been the head of the theory division at Los Alamos in the secret Manhattan Project to build US nuclear weapons during World War II. Following his Ph.D., Rajaraman stayed on at Cornell as a post-doctoral fellow and it was then he met fellow postdoc Frank von Hippel, who went on a decade later to co-found Princeton’s Program on Science and Global Security.
After positions as an assistant professor at Cornell and the University of Southern California, Rajaraman became a member of the Institute for Advanced Study at Princeton in the late 1960s, at the invitation of its director, Robert Oppenheimer. He then returned to India to take up a faculty position in physics at Delhi University, before moving to the Indian Institute of Science in Bangalore (1976-93). He returned to New Delhi in 1994 to join the School of Physical Sciences at Jawaharalal Nehru University, becoming an emeritus professor there in 2004. A gifted educator, he was well known for the clarity and accessibility of his teaching. This carried over into his writing; his book Solitons and Instantons (1982 and 1987) has come to be a key textbook in universities around the world.
As part of his illustrious physics career, Rajaraman held many visiting positions, including at Berkeley, Harvard, MIT, Stanford, the European Centre for Nuclear Research (CERN), and the International Centre for Theoretical Physics (Trieste, Italy). He also spent a second term at the Institute for Advanced Study. Among his physics awards, he received the prestigious Shanti Swarup Bhatnagar Prize for Science and Technology (1985) and the Indian National Science Academy’s S.N. Bose Medal (1995). He served as vice-president of the Indian National Science Academy from 2010 to 2012.
Rajaraman first wrote about India’s nuclear weapon policy in 1970 (four years before India carried out its first nuclear weapon test). In a widely circulated magazine, Illustrated Weekly of India, Rajaraman argued against India pursuing and testing nuclear weapons. He later explained “that article and a few follow-up pieces bought me much grief from the stalwarts of our nuclear establishment, who also wielded considerable power in the larger Indian science community.”
It was another three decades before Rajaraman returned to nuclear policy, spurred by India’s nuclear weapon tests in 1998. He explained that “around that time, I was due to officially retire from my university professorship after nearly 40 years of work on pure physics. It seemed like an opportune time to change my direction of work and devote myself full-time to engaging actively in matters of nuclear policy. The first step would be to enter a period of study and apprenticeship, at the ripe age of 60, in rigorous arms control work.”
He chose to work with Princeton’s Program on Science and Global Security. For a decade, starting in summer 2000, he became an annual summer researcher at the Program as part of its Project on Peace and Security in South Asia (led by the authors, M.V. Ramana and Zia Mian). This project aimed to provide an opportunity for scientists from India and Pakistan outside the respective government nuclear complexes to engage with and provide the public in both their countries with knowledge about nuclear weapons, missiles, and nuclear energy. It sought to model cooperation and dialogue across borders, and to demonstrate the possibility of a shared common understanding of nuclear risks and paths towards peace at a time of hostile nuclear-fueled nationalism.
Along with Rajaraman, and occasionally Sandeep Pandey, also from India, the South Asia group gathered at Princeton included Pakistani physicists Abdul Hameed Nayyar, and Pervez Hoodbhoy. This collaboration produced multiple articles and opinion pieces in academic and popular outlets such as Science and Global Security, Economic and Political Weekly, Bulletin of the Atomic Scientists, and The Hindu.
The leading international science magazine, Nature, highlighted the work of the Princeton Project. A 2008 editorial observed: “scientists and scientific organizations in southeast Asia and in India and Pakistan have not been prominent in issues of disarmament and non-proliferation. This, combined with the lack of non-governmental arms-control organizations in the region, has given the nuclear establishments in India and Pakistan a monopoly over expertise and advice, and inhibited open public debate … one has to look to Princeton University in New Jersey to find a programme bringing together Indian and Pakistani researchers to work on the nuclear threat. Here a handful are studying, for example, overly trigger-happy warning systems that could result in accidental firings within a three-minute decision window. They are also seeking to inform national policy-makers on the impact of a limited regional nuclear war, and to look at ways to limit a south Asian arms race.”
Rajaraman brought to this work a powerful combination of rigorous technical analysis and clear thinking, a mixture of pragmatism and idealism, and a commitment to democracy and education. He collected his ideas and reflections and his experiences working on nuclear policy in his 2023 book Critical Mass: Decoding India’s Nuclear Policy (Bloomsbury India).
Rajaraman was a citizen-scientist committed to informing public debate about nuclear weapons and associated risks in South Asia and beyond. He saw a key goal of his work on nuclear policy as helping meet “the public’s right to know the essential elements of strategic issues affecting the country.” Rajaraman considered it vital to bring democracy to bear on nuclear policy and the way to do this was “to educate the public through its parliamentarians, the intelligentsia in universities, the media and think tanks.” He also became a resource for Indian civil society groups interested in nuclear issues.
In late 2003, after returning to India from his summer in Princeton, he reported with some satisfaction that he had given the keynote lecture on the dangers of nuclear weapons at the inaugural session of a gathering of about 600 people at the national people’s science forums held at Shimla. “This was my first real contact with them, and I was quite impressed. Their organization has about 300,000 to 400,000 members who are mostly dedicated grass root workers spreading literacy and awareness of rights of women, Dalits and so on. I talked in a colloquial mix of Hindi and English, and it seems to have gone over well.”
He became a tireless and pragmatically constructive advocate of the need for responsible policies that further the goals of nuclear disarmament, peace, and development. Rajaraman said, he “started arguing for keeping the nuclear arsenal small and deploying warheads safely in a state of de-alert. To counter nuclear hawks, I also began presenting analyses of India’s official nuclear doctrine to show that it really did not call for too many warheads. I also hoped to help clarify, in this process, to the public and the decision-makers the full implications of possessing and using these weapons.”
Rajaraman was recognized for his work on nuclear policy in South Asia. Rajaraman and one of the authors (MVR) were jointly selected for the American Physical Society’s Leo Szilard Award in 2014. The citation reads: “For outstanding contributions to promote global security issues, through critical analyses of nuclear weapons and nuclear energy programs in India and associated risks in the subcontinent, and efforts to promote peace and nuclear security in South Asia through extensive engagements and writings.”
Rajaraman’s engagement in the Indian nuclear policy debate came at a cost, however. He recalled “instances of unpleasant interactions … with the Indian strategic establishment, varying from indifference to rudeness to outright hostility.” This “establishment” included the Indian Ministry of External Affairs [MEA] and the Department of Atomic Energy Ministry [DAE]. He also observed ruefully that he “could never get a hearing from the decision-makers in the Indian government or the Parliament.”
In 2007, Rajaraman accepted the position and responsibilities of co-chair of the Princeton-based International Panel on Fissile Materials (IPFM), an independent group of experts from 17 countries working on initiatives to reduce global stockpiles and end production and use of highly enriched uranium and plutonium, the key ingredients in nuclear weapons. He was the panel co-chair until 2016, together with Frank von Hippel.
Rajaraman knew that choosing to take up a leadership role with IFPM would create problems explaining that “co-leading such an independent, international group headquartered abroad would not sit well with the Indian officialdom or our strategic community… In fact, I had already run into some unpleasantness from Indian diplomats even before becoming the co-chair.” One key instance came when Rajaraman tried to organize an IPFM meeting in New Delhi. India’s Foreign Ministry denied permission for the meeting. In its report that India had blocked the IPFM meeting, Nature quoted Rajaraman as saying, “I’m hopping mad.”
Rajaraman was welcomed and became well known in the global community of officials, analysts, and activists interested in nuclear weapons policies in many different countries. He made presentations about the work of the IPFM and nuclear risks in South Asia at many high-level international and United Nations conferences. In one year, he traveled and gave talks in Moscow, Tokyo, Washington DC, Copenhagen, Singapore, Erice, Dubai, Bangkok, Ditchley Park, Seoul, and Vienna.
Rajaraman was committed to the importance of science and scientists in informing public debates on nuclear policy. He was a member of the editorial board of the Princeton-based peer-reviewed technical journal Science and Global Security and served on the Science and Security Board of the Bulletin of Atomic Scientists (2009-2014), which sets the “Doomsday Clock.” For over a decade, he was involved with the work of Pugwash, the international scientists’ movement for nuclear disarmament, which received the Nobel Peace Prize for its work, and a member of the Pugwash Council from 2013-2018. He also mentored many younger scientists and analysts, encouraging their work and sharing his expertise and knowledge freely.
He is survived by his wife, Indira Rajaraman, an eminent Indian economist, their child Bittu Kaveri Rajaraman, currently an Associate Professor of Biology and Psychology, and granddaughter Minnal.
Article originally published in the Bulletin of the Atomic Scientists, August 18, 2025.