Trajectory Approach to Two-State Kinetics of Single Particles on Sculpted Energy Landscapes

David Wu, Kingshuk Ghosh, Mandar Inamdar, Heun Jin Lee, Scott Fraser, Ken Dill, and Rob Phillips

We study the trajectories of a single colloidal particle as it hops between two energy wells which are sculpted using optical traps. Whereas the dynamical behaviors of such systems are often treated by master-equation methods that focus on particles as actors, we analyze them instead using a trajectory-based variational method called maximum caliber (MaxCal). We show that the MaxCal strategy accurately predicts the full dynamics that we observe in the experiments: From the observed averages, it predicts second and third moments and covariances, with no free parameters. The covariances are the dynamical equivalents of Maxwell-like equilibrium reciprocal relations and Onsager-like dynamical relations.

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