Structural relaxation, dynamical arrest, and aging in soft-sphere liquids.

We investigate the structural relaxation of a soft-sphere liquid quenched isochorically (ϕ = 0.7) and instantaneously to different temperatures T above and below the glass transition. For this, we combine extensive Brownian dynamics simulations and theoretical calculations based on the non-equilibrium self-consistent generalized Langevin equation (NE-SCGLE) theory.

"Inner clocks" of glass-forming liquids.

Providing a physically sound explanation of aging phenomena in non-equilibrium amorphous materials is a challenging problem in modern statistical thermodynamics. The slow evolution of physical properties after quenches of control parameters is empirically well interpreted via the concept of material time (or internal clock) based on the Tool-Narayanaswamy-Moynihan model. Yet, the fundamental reasons of its striking success remain unclear.

Non-equilibrium relaxation and aging in the dynamics of a dipolar fluid quenched towards the glass transition.

The recently developed non-equilibrium self-consistent generalized Langevin equation theory of the dynamics of liquids of non-spherically interacting particles [20167975] is applied to the description of the irreversible relaxation of a thermally and mechanically quenched dipolar fluid. Specifically, we consider a dipolar hard-sphere liquid quenched (at= 0) from full equilibrium conditions towards different ergodic-non-ergodic transitions. Qualitatively different scenarios are predicted by the theory for the time evolution of the system after the quench (> 0), that depend on both the kind of transition approached and the specific features of the protocol of preparation.

Magnetic viscoelastic behavior in a colloidal ferrofluid.

Based on the stochastic Langevin equation, we derived the total friction experienced by a tracer particle diffusing in thermally equilibrated colloidal magnetic fluids. This transport property leads to new expressions for its long-time diffusion coefficients, which satisfy an Einstein relation with the frictions of its translational and rotational Brownian motion. Further use of the nano-rheology theory allowed us to derive also the viscoelastic modulus of the colloid from such a property.