Independence of the relaxation of a supercooled fluid from itsmicroscopic dynamics: Need for yet another extension of themode-coupling theory

Abstract

Using Brownian dynamics computer simulations, we show that therelaxation of a supercooled Brownian system is qualitatively thesame as that of a Newtonian system. In particular, near theso-called mode-coupling transition temperature, dynamicproperties of the Brownian system exhibit the same deviationsfrom power law behavior as those of the Newtonian one. Thus,similar dynamical events cut off the idealized mode-couplingtransition in Brownian and Newtonian systems. We discussimplications of this finding for extended mode-coupling theory.In addition, we point out and discuss the difference between ourfindings and experimental results, and present an alternativeinterpretation of some of our simulation data.