PROFESSOR A.K. SOOD

This talk will cover three of our most recent studies of active particles illustrating the power of simple table top experiments to discover novel issues in nonequilibrium physics. (i) Flocking, a self-organized motion of vast numbers of creatures like ants, locusts, birds, fishes and animals in a single direction is a spectacular example of emergent order. I will discuss our recent work to understand this phenomenon by working with inanimate polar active granular objects[1], (ii) Sorting of active granular rods based on the activity[2], and (iii) a micrometer sized Sterling heat engine operating between reservoirs having active particles[3]. In the last example, we show that a micrometer-sized active Stirling engine with very high efficiency can be realized by periodically cycling a colloidal particle in a time-varying harmonic optical potential across bacterial baths at different activities in contrast to thermal reservoirs. [1] Nitin Kumar, Harsh Soni, S. Ramaswamy and A.K. Sood, Flocking at a distance in active granular matter, Nature Communications, 5:4688/DOI:10.1038/ncomms5688 (3 September, 2014) [2] Nitin Kumar, Harsh Soni, Rahul Kumar Gupta, Sriram Ramaswamy and A.K. Sood, Sorting motile rods by activity Condmat arxiv 1603.08535 (2016) [3] Sudeesh Krishnamurthy, Subho Ghosh, Dipankar Chatterji, Rajesh Ganapathy and A.K. Sood, A Micrometer-sized Heat Engine Operating Between Bacterial Reservoirs. Condmat arxiv 1601.03130 (2016)