Time-resolved correlation: a new tool for studying temporally heterogeneous dynamics

Abstract

We introduce a new scheme for investigating temporally heterogeneous dynamics, which is termed time-resolved correlation (TRC). TRC is applied to data obtained by diffusing wave spectroscopy probing the slow dynamics of a strongly aggregated colloidal gel. Other examples of TRC data, collected for different jammed materials in single and multiple scattering, are provided to demonstrate the wide range of applicability of this method. In all cases we find evidence that the slow dynamics results from a series of discrete steps rather than from a continuous motion, suggesting temporal heterogeneities to be a general feature of slow dynamics in jammed systems.

Spontaneous Relaxation in Generalized Oscillator Models with Glassy Dynamics

“…For a recent discussion of these ideas see [4,5]. The existence of these two heat exchange processes is at the root of the intermittency phenomenon recently observed in glasses and colloids [2,3].…”

Fluctuations in the time variable and dynamical heterogeneity in glass-forming systems

“…that it is faster in some regions and slower in others [2][3][4]. Direct microscopic evidence for this behavior has been found both in simulations [4,5] and in experiments [4,[6][7][8][9][10][11][12][13][14][15][16]. The understanding of dynamical heterogeneity is believed to be crucial to explain anomalous behavior of materials near the glass transition, and even possibly to explain the very presence of the glass transition itself [2].…”

Mapping Dynamical Heterogeneity in Structural Glasses to Correlated Fluctuations of the Time Variables

“…For systems in the vicinity of the glass transition, experiments and simulations have shown the emergence of spatially heterogeneous dynamics (SHD): mesoscopic regions relax either much faster or much slower than neighboring regions [1][2][3][4][5][6][7][8]. SHD is believed to be crucial to the understanding of non-exponential relaxation, the breakdown of the coupling between translational diffusion and viscosity, and even possibly the slowdown of the dynamics itself [1,2].…”

“…We have used data from molecular dynamics simulations of atomistic systems to apply the test, but the same procedure can be applied to particle tracking data from colloidal [4] and granular systems [8], and slight modifications would allow the study of light scattering [7] or dielectric noise [5] data. This opens the door to investigating the possibility of a unified theoretical explanation of dynamical heterogenity for molecular liquids, colloidal liquids and granular systems.…”