Ashoke Sen becomes first Indian physicist to receive Oskar Klein Medal

Ashoke Sen, a renowned theoretical physicist and professor at the Bengaluru-based International Centre for Theoretical Sciences (ICTS), has become the first Indian physicist to receive the prestigious Oskar Klein Medal, recognizing his contributions to modern theoretical physics and the development of string theory.

Sen, who holds the ICTS-Infosys Madhava Chair Professorship, is internationally recognized for his pioneering research on S-duality, the precise counting of black-hole entropy, and string field theory.

His work has contributed to efforts to understand fundamental aspects of the universe through string theory, a theoretical framework that seeks to describe the fundamental constituents of nature and their interactions.

As part of the recognition, Sen delivered the 2026 Oskar Klein Memorial Lecture, titled "Gravity from Strings and Strings from Gravity," at Stockholm University's AlbaNova Centre on Oct 22, 2026.

The award places Sen among a distinguished group of physicists whose contributions have been recognized through the medal. His research has played an important role in shaping modern string theory, particularly through work on the mathematical structures and theoretical principles underlying the field.

Ashoke Sen's research contributions to string theory

Sen is widely known for his work on several fundamental problems in theoretical physics, including S-duality, black-hole entropy, and string field theory. These areas of research address questions about the mathematical consistency of string theory and the relationship between gravity and quantum physics.

S-duality concerns relationships between different descriptions of a physical theory, allowing phenomena that may be difficult to understand in one formulation to be examined through another. Sen's contributions to this area have helped advance the theoretical understanding of string theory and its underlying principles.

His research on black-hole entropy has also contributed to efforts to understand how black holes can be described in terms of microscopic states. The precise counting of these states is an important problem in theoretical physics because it connects the properties of black holes with concepts from quantum mechanics and statistical physics.

Sen's work on string field theory has further contributed to the development of mathematical approaches to describing strings and their interactions. Together, these research contributions have helped shape the study of string theory and its role in attempts to understand the fundamental laws of nature.

Physicist has received several international and national honors

The Oskar Klein Medal adds to Sen's extensive list of national and international honors for his contributions to theoretical physics.

In 2012, he received the Breakthrough Prize in Fundamental Physics for his contributions to establishing a unifying framework for string theory. Two years later, in 2014, he was awarded the Dirac Medal in recognition of his work in the field.

His other honors include the Infosys Prize in Mathematical Sciences in 2009, the Shanti Swarup Bhatnagar Prize in 1994, and the ICTP Prize in 1989. These awards recognize his contributions to mathematical and theoretical physics at different stages of his career.

Sen has also received some of India's highest civilian and scientific honors. He was awarded the Padma Shri in 2001 and the Padma Bhushan in 2013 for his contributions. In 1998, he was elected a Fellow of the Royal Society, one of the world's oldest scientific academies.

The range of awards reflects the international recognition of Sen's research and its influence on theoretical physics, particularly in areas connected with string theory and the fundamental structure of the universe.

ICTS director congratulates Ashoke Sen on the achievement

Congratulating Sen on receiving the medal, ICTS Director Rajesh Gopakumar said, “It has been no less than wonderful having Ashoke with us and setting the tone for excellence here at ICTS.”

Sen serves as an ICTS-Infosys Madhava Chair Professor at the Bengaluru-based institution, which supports research in theoretical sciences. His work and academic presence form part of the institution's broader research environment, which brings together scientists working on fundamental questions across theoretical disciplines.

The recognition also highlights the contributions of Indian scientists to international research in theoretical physics. Sen's achievement places an Indian physicist among the recipients of an award associated with major advances in the field.

About the Oskar Klein Medal

Named after Swedish theoretical physicist Oskar Klein, the Oskar Klein Medal is awarded annually by Stockholm University and the Nobel Committee for Physics of the Royal Swedish Academy of Sciences.

Established in 1988, the award recognizes distinguished contributions to physics. It honors scientists whose research has advanced understanding in the field and contributed to the development of important theoretical or experimental ideas.

The medal has previously been awarded to several prominent physicists, including Nobel laureates Chen-Ning Yang, Steven Weinberg, and Hans Bethe. They received the honor during the award's first three years, respectively.

Sen's selection adds his name to this distinguished group of physicists and marks a milestone for Indian theoretical physics, recognizing his sustained contributions to string theory and the study of fundamental questions in modern physics.