The International Centre for Theoretical Sciences on Monday (August 10, 2026) said that its professor Deepak Dhar has been awarded the prestigious 2026 Dirac Medal, recognising his contributions to statistical mechanics and complex systems.
Why It Matters
“Through his pioneering work on the sandpile model, for example, he described a familiar phenomenon: as grains are added to a sandpile, most result in no change or only small avalanches, while occasionally a single grain can cause a much larger collapse. Dhar and his collaborators then developed the so-called Abelian sandpile model as a mathematical version of the sandpile idea. ‘Abelian’ means no matter in which sequence grains topple and cascade, the pile always settles into the same final shape. This was Dhar’s important insight — a property that lets physicists calculate exact answers and thus predict the final shape.
The award recognises the four scientists “for their pioneering contributions to equilibrium statistical mechanics and for extending its concepts and methods into non-equilibrium statistical mechanics, optimization problems, theoretical neuroscience, and, finally, artificial intelligence”, according to the ICTS.
How It Works
Scientists have used it to model earthquakes, the spread of forest fires, bursts of activity in neural networks in the brain, and fluctuations in financial markets. After finishing his doctorate, Dhar returned to India rather than stay in the U.S., and spent most of his career at the Tata Institute of Fundamental Research, Mumbai, before moving to the Indian Institute of Science Education and Research (IISER), Pune, in 2016. Because it captures a very general kind of behaviour: of systems that build up some kind of instability until they can release it in unpredictable ways, the Abelian sandpile model has numerous applications fundamentally.
“The theory shows that the sandpile, like many other complex systems, spontaneously places itself in a critical regime where small effects can sometimes trigger large abrupt events and has been used to model systems as apparently different as earthquakes, traffic jams and fluctuations in financial markets,” it said.
