Finite-size Scaling Study of Shear Viscosity Anomaly at Liquid-Liquid Criticality

We study equilibrium dynamics of a symmetrical binary Lennard-Jones fluid mixture near its consolute criticality. Molecular dynamics simulation results for shear viscosity, $\eta$, from microcanonical ensemble are compared with those from canonical ensemble with various thermostats. It is observed that Nos\'{e}-Hoover thermostat is a good candidate for this purpose and so, is adopted for the quantification of critical singularity of $\eta$, to avoid temperature fluctuation (or even drift) that is often encountered in microcanonical simulations. Via finite-size scaling analysis of our simulation data, thus obtained, we have been able to quantify even the weakest anomaly, of all transport properties, that shear viscosity exhibits and confirm the corresponding theoretical prediction.