Signatures of dynamic heterogeneity from a generalized hydrodynamic model of the supercooled liquid

2014/02/14 by Gupta, Bhaskar Sen, Das, Shankar P.
#FOS: Physical sciences #Statistical Mechanics (cond-mat.stat-mech)

paper · doi:10.48550/arxiv.1402.3404

Abstract

In this paper we study the four point correlation function χ₄ of collective density fluctuations in a nonequilibrium liquid. The equilibration is controlled by a modified stretched exponential behavior ( exp [-(t_w/τ)^β] ) having the relaxation time τ dependent on the aging time t_w. Similar aging behavior has been seen experimentally in supercooled liquids. The basic equations of fluctuating nonlinear hydrodynamics (FNH) are solved here numerically to obtain χ₄ for equilibrium and non equilibrium states. We also identify a dynamic length scale ξ from the equilibrated function. ξ(T) grows with fall of temperature T. From a broader perspective, we demonstrate here that the characteristic signatures of dynamical heterogeneities in a supercooled liquid, observed previously in computer simulations of the dynamics of a small number of particles, are also present in the coarse grained equations of generalized hydrodynamics.

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