Mechanical signature of non-reciprocal dynamics in active self-assembly

An active particulate system bound within a circular external potential of varying steepness is studied in-silico. Individual particles interacting pair-wise via a soft repulsive potential are considered to align their velocities with the mean orientation of their immediate neighbours. Such alignment rule results into non-reciprocal forces which in turn is manifested into emergent collective motion. The steady state structural properties of this system has already been charted in detail in the activity-steepness parameter space. The system goes from a rotating disordered phase to a rolling ordered phase as a function Here, we focus on the dynamics of this system under mechanical quench of the confinement. In particular, we attempt to identify and quantify the onset of the non-reciprocal dynamical transition in terms of space-time correlations of mechanically relevant variables such as vorticity and positional fluctuations.