Self-induced temperature gradients in Brownian dynamics

Abstract

Brownian systems often surmount energy barriers by absorbing and emitting heat to and from their local environment. Usually, the temperature gradients created by this heat exchange are assumed to dissipate instantaneously. Here we relax this assumption to consider the case where Brownian dynamics on a time-independent potential can lead to self-induced temperature gradients. In the same way that externally imposed temperature gradients can cause directed motion, these self-induced gradients affect the dynamics of the Brownian system. The result is a coupling between the local environment and the Brownian subsystem. We explore the resulting dynamics and thermodynamics of these coupled systems and develop a robust method for numerical simulation. In particular, by focusing on one-dimensional situations, we show that self-induced temperature gradients reduce barrier-crossing rates. We also consider a heat engine and a heat pump based on temperature gradients induced by a Brownian system in a nonequilibrium potential.

First-passage time theory of activated rate chemical processes in electronic molecular junctions

“…Beyond this regime, the fluctuationdissipation theorem no longer holds, allowing for the emergence of localized heating effects in analogy to Landauer's proposed blowtorch effect [39,40], in which specific configurations of the reaction coordinate may experience heightened temperatures, which may have a significant affect on the evolution of the system. Such systems are not limited to the realms of molecular electronics; the most common examples include numerous molecular motors, ratchets, and heat engines [41][42][43] as well as various confined nanosystems [44][45][46][47][48], notably of biological significance [49,50]. Several explicit simulations of Landauer's blowtorch effects in double-well potentials have also been performed recently [51][52][53].…”