Position-Dependent Diffusion induced Non-monotonic decay of Certain Non-Equilibrium Phenomena in Condensed Phase

TL;DR

This paper investigates how position-dependent diffusion causes non-monotonic relaxation behaviors in non-equilibrium phenomena within condensed phases, revealing effects not seen with uniform diffusion.

Contribution

It introduces a theoretical framework showing that spatial inhomogeneity in diffusion leads to non-monotonic relaxation, contrasting with traditional exponential decay models.

Findings

Position dependence induces non-monotonic relaxation.

Non-monotonicity depends on spatial inhomogeneity and restoring forces.

Ranges for experimental detection are identified.

Abstract

The dynamics of various optically controlled non-equilibrium phenomena in the condensed phase are studied using the Liouville equation. We study a projection of the same in a slow moving coordinate, identified as the Reaction Coordinate approach, with a position dependent diffusion coefficient. Introduction of position dependence is shown to induce non-monotonicity in relaxations of certain Non-equilibrium correlation functions, previously unexplored in the theoretical as well as experimental studies. This is in contrast to the exponential relaxation of its position independent analogue, irrespective of initial conditions. We characterize the dependence of this non-monotonicity on the strength of spatial inhomogeneity of diffusion and on the strength of the restoring forces and also indicate ranges of combinations where this feature is exhibited to pave the way for its experimental detection.