The work that won Deepak Dhar the Dirac Medal, Pg8

Key Highlights:

• Theoretical physicist Deepak Dhar was awarded the Dirac Medal for his contributions to statistical physics.
• He shares the 2023 award with Bernard Derrida, Marc Mézard, and Haim Sompolinsky.
• Dhar is the second Indian to receive the Dirac Medal, following Ashoke Sen in 2012.
• The award is presented by the International Centre for Theoretical Physics (ICTP) in Trieste, Italy.
• His most notable work involves the Abelian sandpile model, which explains self-organised criticality.

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Detailed Insights:

• The Dirac Medal is awarded annually on Paul A.M. Dirac's birthday for significant contributions to theoretical physics.
• It is explicitly not given to Nobel, Fields, or Wolf Prize laureates, though many recipients later win a Nobel Prize.
• The Abelian sandpile model describes systems where small nudges can trigger effects of varying sizes, from trivial to significant.
• This model is applied to phenomena like earthquakes, forest fires, neural networks, and financial market fluctuations.
• Self-organised criticality refers to systems that naturally evolve into a critical state where small disturbances can have large impacts.
• Deepak Dhar has spent most of his career in India, including at the Tata Institute of Fundamental Research (TIFR) and Indian Institute of Science Education and Research (IISER), Pune.
• He has also received other prestigious awards, including the Shanti Swarup Bhatnagar Prize (1991), TWAS Prize (2002), Padma Bhushan (2023), and the Boltzmann Medal (2022).
• The ICTP was founded in 1964 by Nobel laureate Abdus Salam to foster scientific collaboration, especially for physicists from the Global South.

Scientific/Technical Concepts Involved:

• Abelian sandpile model: A mathematical model describing systems that build instability and release it unpredictably, where the final state is independent of the sequence of events.
• Self-organised criticality: A property of dynamic systems that spontaneously evolve into a critical state, where small perturbations can lead to large-scale events.
• Statistical mechanics: A branch of physics that uses probability theory to study the collective behavior of large ensembles of microscopic entities.