What is Self-Organized Criticality?

Spontaneous emergence of global correlation from local interactions. The dynamics of the system, itself, guides it from a disordered state to an ordered state.

Abundantly seen in nature, and often found in many astrophysical systems. However, the SOC can be studied using toy-models and simple dynamical simulations on structured lattice. My Master’s projects were on the study of SOC for various systems, ranging from 2D sandpile model, Eulerian Walkers, to Brownian Ratchet.

Although, I do not work on these anymore, it turned out to be steady stepping stone in getting into numerical simulations. Some of the old slides and reports are included for anyone interested.

  1. Here’s the link to my first project from the Summer of ‘69 summer of 2013, on the Self-Organized Criticality and Extreme Events.
  2. Another interesting system was that of an Eulerian Walker, often used in Rotor-Router and Electrical Circuits in optimizing efficiency. My focus was on the Dynamics of Eulerian Walkers on 2D lattice.
  3. My final project, and the most detailed work on this, was done on Parrondo’s Paradox and the Brownian Ratchet, where both numerical and analytical studies were carried out on the topic. A detailed report can also be found here.

The takeaway message is small scale dynamics can lead to large scale effects and not to ask Ayan any hard questions on these as these are decade old stuff such phenomena can provide valuable insight into more complex real world systems.