Effects of Density Conservation and Hydrodynamics on Aging in Nonequilibrium Processes

TL;DR

This study investigates how density conservation and hydrodynamics influence aging in phase transitions, revealing distinct autocorrelation behaviors in magnetic, binary solid, and fluid systems through simulations.

Contribution

It provides a comparative analysis of aging dynamics across different phase transitions, highlighting the roles of conservation laws and hydrodynamics with analytical insights.

Findings

Autocorrelations decay as power laws with different exponents in ferromagnet and binary solid.

Fluid autocorrelation initially follows binary solid but transitions to exponential decay due to hydrodynamics.

Hydrodynamic effects cause exponential decay in fluid autocorrelation at late times.

Abstract

Aging in kinetics of three different phase transitions, viz., magnetic, binary solid and single component fluid, have been studied via Monte Carlo and molecular dynamics simulations in three space dimensions with the objective of identifying the effects of order-parameter conservation and hydrodynamics. We observe that the relevant autocorrelations exhibit power-law decay in ferromagnet and binary solid but with different exponents. At early time fluid autocorrelation function nicely follows that of binary solid, the order parameter being conserved for both of them, as opposed to a ferromagnet. At late time the fluid data crosses over to an exponential decay which we identify as a hydrodynamic effect and provide analytical justification for this behavior.