Transition path dynamics of a nanoparticle in a bistable optical trap

TL;DR

This study investigates the transition paths of a nanoparticle in a bistable optical trap, providing detailed experimental insights that benchmark theoretical models of rare event dynamics across various scientific fields.

Contribution

The paper introduces a high-precision experimental approach to directly observe and analyze transition paths of a nanoparticle, offering new benchmarks for theories of transition path dynamics.

Findings

Resolved transition paths with high-speed tracking

Related transition paths to 3D potential properties

Provided benchmarks for existing transition path theories

Abstract

Many processes in chemistry, physics, and biology involve rare events in which the system escapes from a metastable state by surmounting an activation barrier. Examples range from chemical reactions, protein folding, and nucleation events to the catastrophic failure of bridges. A challenge in understanding the underlying mechanisms is that the most interesting information is contained within the rare transition paths, the exceedingly short periods when the barrier is crossed. To establish a model process that enables access to all relevant timescales, although highly disparate, we probe the dynamics of single dielectric particles in a bistable optical trap in solution. Precise localization by high-speed tracking enables us to resolve the transition paths and relate them to the detailed properties of the 3D potential within which the particle diffuses. By varying the barrier height and shape, the experiments provide a stringent benchmark of current theories of transition path dynamics.