Single-particle fluctuations and directional correlations in driven hard-sphere glasses
S. Mandal, V. Chikkadi, B. Nienhuis, D. Raabe, P. Schall, F. Varnik.
Physical Review E, The American Physical Society, 88, 022129, (2013)
Via event-driven molecular dynamics simulations and experiments, we study the packing-fraction and shearrate dependence of single-particle fluctuations and dynamic correlations in hard-sphere glasses under shear. At packing fractions above the glass transition, correlations increase as shear rate decreases: the exponential tail in the distribution of single-particle jumps broadens and dynamic four-point correlations increase. Interestingly, however, upon decreasing the packing fraction, a broadening of the exponential tail is also observed, while dynamic heterogeneity is shown to decrease. An explanation for this behavior is proposed in terms of a competition between shear and thermal fluctuations. Building upon our previous studies [Chikkadi et al., Europhys. Lett. 100, 56001 (2012)], we further address the issue of anisotropy of the dynamic correlations.