Mode-coupling theory predictions for the dynamical transitions of partly pinned fluid systems

Abstract

The predictions of the mode-coupling theory (MCT) for the dynamical arrest scenarios in a partly pinned (PP) fluid system are reported. The corresponding dynamical phase diagram is found to be very similar to that of a related quenched-annealed (QA) system. The only significant qualitative difference lies in the shape of the diffusion-localization lines at high matrix densities, with a reentry phenomenon for the PP system but not for the QA model, in full agreement with recent computer simulation results. This finding clearly lends support to the predictive power of the MCT for fluid-matrix systems. In addition, the predictions of the MCT are shown to be in stark contrast with those of the random first-order transition theory. The PP systems are thus confirmed as very promising models for differentiating tests of theories of the glass transition.

Glassy dynamics of partially pinned fluids: An alternative mode-coupling approach

“…[4] was surprising for two reasons. First, it is usually assumed that modecoupling and RFOT theories are related.…”

“…Here, we will outline a projection operator derivation which is easily compared with Krakoviack's theory [4,22]. Also, following Refs.…”

“…Thus, the analysis of this so-called random pinning glass transition [8] could both shed light on the glass transition itself and provide a new way to test diverse theoretical descriptions used to describe it. In particular, Krakoviack [4] recently argued that two different approaches, the mode-coupling theory [17] and the random first order theory (RFOT) [18] make strikingly different predictions for the glassy behavior of partially pinned systems. Thus, a simulational study of glassy behavior of a partially pinned system could easily disprove one of these approaches.…”

“…P, 64.70.Q, 61.20.Lc, 05.20Jj Recently there have been several theoretical and simulational studies of glassy dynamics of fluid systems in which some particles, randomly selected out of an equilibrium configuration, have been frozen or pinned [1][2][3][4][5][6]8]. Originally these so-called partially pinned systems were considered to be just one special example of a broad class of model porous systems known as quenched-annealed binary mixtures [9][10][11].…”

“…Also, following Refs. [4,22] we will refer to the mobile (un-pinned) particles as the fluid particles and to the pinned ones as the matrix particles. The fundamental dynamical variable used in our theory is the Fourier transform of the microscopic fluid density, n f (q) = N f j=1 e −iq·rj , where r j denotes the position of the jth fluid particle and N f is the number of fluid particles.…”