Indian theoretical physicist Professor Ashoke Sen has become the first Indian physicist to receive the prestigious Oskar Klein Medal for 2026, marking a significant milestone in India's contributions to fundamental physics.
The Bengaluru-based International Centre for Theoretical Sciences (ICTS), where Sen serves as an ICTS-Infosys Madhava Chair Professor, announced the recognition. The medal honours his pioneering contributions to string theory, particularly his work on S-duality, black hole entropy and string field theory.
Sen's academic journey began in Kolkata, where he completed his undergraduate studies in physics at Presidency College in 1975. He subsequently pursued a Master's degree in physics at the Indian Institute of Technology (IIT) Kanpur, graduating in 1978.
He then moved to the United States for doctoral studies, earning a PhD in physics from the State University of New York at Stony Brook in 1982.
Following his doctorate, Sen undertook postdoctoral research at the Fermi National Accelerator Laboratory (Fermilab) in Illinois from 1982 to 1985 and at the Stanford Linear Accelerator Centre (SLAC) from 1985 to 1988.
His academic career in India continued at the Tata Institute of Fundamental Research (TIFR), Mumbai, where he joined as a faculty member in 1988. In 1997, he moved to the Harish-Chandra Research Institute (HRI), Allahabad, where he served as a distinguished professor. He later joined the ICTS in Bengaluru.
Who is Ashoke Sen?
Sen is internationally recognised for his contributions to string theory, a theoretical framework that seeks to explain the fundamental building blocks of the universe and the forces governing them.
Unlike conventional approaches that treat elementary particles as point-like objects, string theory proposes that the fundamental constituents of nature may be tiny, vibrating strings. Different vibrational patterns are associated with different particles.
One of Sen's major contributions is his work on S-duality, which established relationships between different formulations of string theory. His research on the microscopic structure of black holes and their entropy has also helped advance the understanding of some of the most challenging questions in theoretical physics.
His work on string field theory has further contributed to the mathematical framework used to study string interactions.
List of Ashoke Sen's honours
Sen delivered the 2026 Oskar Klein Memorial Lecture, titled 'Gravity from Strings and Strings from Gravity', at Stockholm University's AlbaNova Centre on October 22.
The Oskar Klein Medal, named after Swedish theoretical physicist Oskar Klein, was established in 1988. It is awarded annually by Stockholm University and the Nobel Committee for Physics of the Royal Swedish Academy of Sciences to recognise distinguished contributions to physics.
Previous recipients include Nobel laureates Chen-Ning Yang, Steven Weinberg and Hans Bethe, who received the medal in its first three years, respectively.
Sen's latest recognition adds to a distinguished list of awards. He received the Breakthrough Prize in Fundamental Physics in 2012 for his contributions to establishing the unifying structure of string theory and the Dirac Medal in 2014.
His other honours include the Infosys Prize in Mathematical Sciences in 2009, the Shanti Swarup Bhatnagar Prize in 1994 and the ICTP Prize in 1989. The Government of India conferred the Padma Shri on him in 2001 and the Padma Bhushan in 2013. He was also elected a Fellow of the Royal Society in 1998.
"On behalf of all of us, very warm congratulations to Ashoke. It has been no less than wonderful having Ashoke with us and setting the tone for excellence here at ICTS," PTI quoted ICTS Director Rajesh Gopakumar.
