Who is Deepak Dhar? Indian physicist who worked with Richard Feynman wins Dirac Medal previously won by Stephen Hawking

International Centre for Theoretical Sciences professor Deepak Dhar has been awarded the prestigious 2026 Dirac Medal for his contributions to statistical mechanics and complex systems, the institute said on Monday.

Dhar, an Indian National Science Academy distinguished professor at ICTS, shares the honour with Bernard Derrida, Marc Mezard and Haim Sompolinsky. The award recognises their pioneering work in equilibrium statistical mechanics and the extension of its concepts and methods to non-equilibrium systems, optimisation problems, theoretical neuroscience and artificial intelligence.

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Dirac Medal and its legacy

The Dirac Medal is awarded annually by the International Centre for Theoretical Physics (ICTP) in honour of physicist Paul Dirac. Instituted in 1985, the award has over the years been associated with several prominent figures in theoretical physics, including Stephen Hawking.

ICTP Director Atish Dabholkar said the work of the 2026 medallists has helped establish theoretical physics, particularly statistical mechanics, as a framework for addressing a broad range of problems extending into fields such as biology, computer science and artificial intelligence.

Dhar's work on complex systems

The award citation highlighted Dhar's research into how simple interactions can produce complex and sometimes unpredictable behaviour in large systems.

His pioneering work on the sandpile model demonstrated how adding grains to a sandpile generally produces no change or small avalanches, while occasionally causing a much larger collapse.

The theory shows how a sandpile can spontaneously reach a critical state in which small changes can trigger sudden, large-scale events. The model has been used to study phenomena including earthquakes, traffic jams and fluctuations in financial markets.

Dhar's burning algorithm, developed in connection with sandpile models, became an influential concept in research on self-organised criticality and complex systems.

From Pratapgarh to Caltech

Born in 1951 in Pratapgarh, Uttar Pradesh, Dhar grew up in a Hindi-medium environment. His mother wanted him to become an IAS officer, while his father encouraged his interest in science by regularly bringing home science magazines.

One publication, Understanding Science, made a lasting impression on Dhar and helped nurture his early curiosity about science.

He studied at Allahabad University before moving to IIT Kanpur for his MSc. He later joined the California Institute of Technology (Caltech) in the United States on a Richard Feynman fellowship.

At Caltech, Dhar worked closely with renowned physicist Richard Feynman and served as his teaching assistant. He completed his PhD in 1978.

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Return to India

After completing his doctorate, Dhar chose to return to India rather than pursue a long-term career in the United States. He joined the Tata Institute of Fundamental Research (TIFR) in Mumbai, where he became part of a strong community of theoretical physicists.

Dhar also served as a professor at IISER Pune for nearly eight years, according to his LinkedIn profile, contributing to the development of physics and teaching hundreds of students.

At TIFR, he worked without a formal mentor but developed his research in a strong theoretical physics environment. Over the following four decades, he made major contributions to statistical physics and the study of complex systems.

His work on sandpile models and self-organised criticality remains among his best-known contributions and forms an important part of the research recognised by the 2026 Dirac Medal.