Nonvibrating granular model for a glass-forming liquid: Equilibration and aging

Area of Science:

• Condensed Matter Physics
• Granular Systems
• Nonlinear Dynamics

Background:

• Glass-forming liquids exhibit complex dynamics near the glass-transition temperature.
• Understanding aging and structural relaxation is crucial for materials science.

Purpose of the Study:

• To experimentally investigate the dynamic and structural evolution of a glass-forming liquid model.
• To analyze the effects of sudden temperature quenching on system equilibration and aging.

Main Methods:

• Utilized a magnetic granular system under an unsteady magnetic field as a model for glass-forming liquids.
• Performed sudden quenching experiments to drive the system to lower temperatures.
• Measured mean-squared displacement and radial distribution function to characterize dynamics and structure.
• Analyzed intermediate scattering function and effective inter-particle potential.

Main Results:

• Rapid equilibration observed when quenching to liquid states far from the glass transition.
• Systems quenched below the glass-transition temperature also equilibrate quickly.
• Intermediate quenching temperatures below the glass transition induce slow aging dynamics.
• Particle aggregation and formation of stable clusters observed due to attractive interactions.
• Emergence of a deeper attractive well in the effective potential leads to inhomogeneities and frustrated aging.

Conclusions:

• The system's aging process is influenced by the interplay between repulsive and attractive inter-particle forces.
• Inhomogeneities arising from particle aggregation significantly impact the aging dynamics.
• The model system demonstrates a transition from aging to aggregation-driven structural evolution.