Numerical temperature measurement in far from equilibrium model systems

We used a spherical piece of a solid crystal as a thermometer to measure the temperature of far from equilibrium model fluids thermostatted by a numerical feedback mechanism. The thermometer, consisting of 135 or 321 small particles, was devised to behave like one of the fluid particles in order to maintain the homogeneity of the dissipative dynamical system. We found the temperature determined by the random velocities in the close-to-equilibrium thermometer to be substantially different from the kinetic temperature of the studied nonequilibrium molecular dynamics models. We discuss the implications of our results.