String theory pioneer Ashoke Sen becomes first Indian to win 2026 Oskar Klein Medal

Indian physicist Ashoke Sen has been awarded the 2026 Oskar Klein Medal, becoming the first Indian physicist to receive the honour.

Sen, an ICTS-Infosys Madhava Chair professor at the International Centre for Theoretical Sciences (ICTS)-Tata Institute of Fundamental Research (TIFR), Bengaluru, is widely regarded as an architect of modern string theory.

The theory postulates that the elementary constituents of matter are tiny one-dimensional, string-like objects instead of point particles. It thus tries to put forth a unifying description for matter and forces between them.

Established in 1988 and named after the Swedish theoretical physicist Oskar Klein, the medal is awarded annually by Stockholm University and the Nobel Committee for Physics of the Royal Swedish Academy of Sciences.

Honouring the memory of Klein, the organising committee of the Oskar Klein Memorial Lectures every year invites a distinguished researcher to give a memorial lecture and to receive the Klein medal.

Sen gave the lecture, titled 'Gravity from strings and strings from gravity', on October 22 at the AlbaNova University Centre in Stockholm.

The talk described how string theory leads to a consistent quantum theory of gravity and addresses outstanding puzzles involving quantum theory of black holes.

Contributions of the Padma Shri (2001) and Padma Bhushan (2013) recipient have helped shape the research field through a series of influential theoretical breakthroughs, including work recognised by the Breakthrough Prize in Fundamental Physics in 2012, which helped establish the idea that all string theories represent different limits of the same underlying theory.

ICTS Director Rajesh Gopakumar congratulated Sen, saying, "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."

In a statement, the ICTS said, "Prof. Sen, an ICTS-Infosys Madhava Chair Professor, is internationally recognised for his pioneering work on S-duality, the precision counting of black-hole entropy and string field theory, all of which have helped shape modern string theory."

Past recipients of the Oskar Klein Medal include Kip Thorne in 2016, Peter Higgs in 2009, Stephen Hawking in 2003, and Nobel Prize recipients Hans E. Bethe in 1990, Steven Weinberg in 1989 and Chen Ning Yang in 1988.