Guest Lecture: Arnab Saha

Flow of Information in Living Systems

Dr. Saha is a faculty in the Department of Physics, University of Calcutta (India). He did his PhD from 2006 - 2011 in S.N.Bose National Center For Basic Sciences (SNBNCBS, India) on Stochastic Thermodynamics which is a topic under Nonequilibrium Statistical mechanics. Then moved to Max Planck Institute of the Physics For Complex Systems (MPIPKS, Germany) in Dresden, Germany for his post doctoral study from 2011 - 2014. Next he moved to his second post doctoral position in Heinrich Heine University, Düsseldorf, Germany where he was from 2014-2016. In his post doctoral period his research interest was Active Matter Physics which includes collective dynamics of living organisms across the scales i.e. starting from cells in tissues to birds in flocks. Currently he works both on Active Matter Physics and Stochastic Thermodynamics and sometimes in their interface. In 2016 he got the faculty position in India and continue working in India. He is currently Fellow-in-residence at CYAS, invited by the LPTM research center.

Living entities in a group communicate and transfer information to one another for a variety of reasons. It might be for foraging food, migration, or escaping from obstacles and threats that may appear suddenly. They do so by interacting with each other and also with the environment. Statistical mechanics and information theory can be useful to develop the tools to quantify and analyse the flow of information among the living entities. The living entities can be modelled as active (i.e. self-propelling) particles. Here we consider a group of active particles under confinement. First we will show that the self-organisation of the particles can crucially depend on whether the confinement is soft or hard. Then we quench the trap boundary from soft to hard instantaneously. Consequently the self-organised cluster of the active particles, which was stable when the boundary was soft, becomes unstable and undergoes extreme deformation after the quench to find another stable configuration suitable for the hard boundary. Finally we will quantify the information regarding the quench that flows throughout the individual particles of the deforming cluster and show that the flow spans the whole cluster, propagating ballistically.

Date: April 29th, 2025 from 2pm to 3pm.

The hybrid guest lecture is organised in person at the H008 meeting room of MIR in Neuville-sur-Oise and remotely on Zoom.

To attend the remote guest lecture, please connect to Zoom: https://cyu-fr.zoom.us/j/97548677167

The video will be online on the CY AS YouTube channel