The role of Configurational entropy in real time mass sensing.*

We present a theoretical framework for determining the mass de- posited on a mechanical resonator subject to a flux of incoming particles of a single species. We consider the specific example of a vibrating nanostring and infer the history of mass deposition events from the frequency shifts in real time using a numerical optimization algorithm that correctly compensates for the configurational entropy. Our approach is tested against simulated data and is shown to perform well. We extend this model for a two particle system and try to comment on its applicability over a multi-particle deposition.