Professor Rajarshi Chakrabarti

Professor Rajarshi Chakrabarti
Department of Chemistry
Indian Institute of Technology Bombay
Abstract

Statistical Mechanics of active polymers: from dilute to dense phase

Colloidal chains driven by local chemical reactions [1] or in a bath of bacteria [2] show unusual scaling behavior, not observed in equilibrium. In the first part of the talk, I will briefly discuss some analytically solvable models for a single active polymer chain or a passive polymer chain in active baths [3-5]. These models can actually predict experimentally observed superdiffusive motion of the tagged monomer of a colloidal chain in an active bacteria bath. These models also predict swelling of active chains in passive baths and passive chains in active baths, longtime enhanced diffusion as seen in experiments [1-2]. To understand the motion of active shape- deforming agents, a collection of rings made of active Brownian particles (ABPs) [3, 4] for different packing fractions and activities is investigated using computer simulations. This will be the topic for the second part of my talk. Our computer simulations reveal that active rings display a novel dynamic clustering [5] instead of the conventional motility- induced phase separation (MIPS) [6] as observed in case of collection of ABPs. Surprisingly, increasing packing fraction of rings exhibits a non-monotonicity in the dynamics due to the formation of a large number of small clusters. The conformational fluctuations of the polymers suppress MIPS exhibited by ABPs. This demonstrates a complex interplay between activity, topology, and connectivity.

Rajarshi Chakrabarti

Professor Rajarshi Chakrabarti received his Ph.D. in Theoretical Chemistry from the Indian Institute of Science, Bengaluru. After two postdoctoral stints at the University of Illinois at Urbana Champaign and the University of Stuttgart, he joined the Department of Chemistry, Indian Institute of Technology Bombay, as an Assistant Professor in 2013 and became a full Professor in 2021. His research interests are broadly in the area of Statistical Mechanics and Soft and Living Matter. Currently, he is serving as an Editorial Board Member of Journal of Physics A: Mathematical and Theoretical. Research Website: rajarshichakrabarti.wixsite.com/rajarshichakrabarti

Hosted by Professor Sapna Sarupria.