Non-equilibrium molecular dynamics of jamming in thermostatted shear flows

Jamming is a physical phenomenon that occurs in many different systems on a multitude of length scales, from colloids in microchannels to granular particles in silos to vehicles in traffic. Jamming is a striking example of how 'microrheology'—microscopic particle interactions and configurations—can generate surprising macroscopic response. However, the underlying nature of jamming, and the physical mechanisms which lead to its onset, remain a topic of intense debate. In this work, we perform non-equilibrium molecular dynamics simulations of sheared colloidal suspensions where different definitions of the system temperature (e.g. kinetic or configurational temperature) are thermostatted [1,2].
The thermostat modifies the equation of motion of the particles in the system, mimicking the influence of the interstitial fluid. We examine the influence of the choice of the definition of temperature on the jamming behaviour in the system. The aim of this work is to create a thermostat which adequately reproduces the hydrodynamic interactions and the jamming response in a densely packed colloidal suspension. We study jamming statistics from the simulation such as fluctuations and time correlations in the pressure and viscosity, as well as the definition of the temperature, and compare them with similar statistics from an experimental sheared colloidal suspension.