Alladi Ramakrishnan Hall

Coarse-grained description for the time evolution of a many-particle system

Shankar Prasad Das

JNU, New Delhi

The continuum field theoretic approach to describing a many-particle system has been very useful in understanding its thermodynamic and time-dependent behaviour. Our discussion will be on the fluctuating hydrodynamic description used to study the behaviour of a system of passive systems and the active matter of self-propelled particles. The dynamics are primarily formulated in terms of a set of collective modes of the system. We discuss how starting from a set of microscopic balance equations for the collective modes, the coarse-grained description with smooth spatiotemporal dependencies is obtained. We demonstrate that the appearance of the self-propelling terms and the breaking of Galilean invariances in the equations for the active-matter hydrodynamics are linked to the equations of motion of the individual particles.