Escape and synchronization of a Brownian particle.

Brownian movement is a classic of statistical physics. In his seminal work, Kramers (I~ developed a theory on the thermally activated escape from a potential well. In a recent letter, (2~ we present a visualization of the escape of a 1-#m Brownian particle at room temperature in water and show that the theory is quantitatively verifiable in the overdamped regime. Using the technique of optical traps, we localize the particle in a double potential well created by two optical traps and study its escape. We then enrich the dynamics by temporal modulation of the well (3) and observed the proposed stochastic synchronization of Benzi et alJ 4) This is a model system for a wide range of phenomena in nature, from neuronal action potentials to muscular motility, and even climate change. The concept invoked is always synchronization of a stochastic escape within a double potential well. As far as we know, this is the first experiment directly analyzing the process for a particle in a double well, subjected to intrinsic thermal activation.