Does the Adam-Gibbs relation hold in simulated supercooled liquids?

Area of Science:

• Condensed Matter Physics
• Materials Science
• Statistical Mechanics

Background:

• The glass transition is a fundamental phenomenon in condensed matter physics, characterized by a dramatic increase in viscosity and relaxation times.
• Thermodynamic theories attempt to explain the glass transition by relating dynamics to properties like configurational entropy.
• The Adam-Gibbs relation is a key theoretical link between configurational entropy and relaxation times.

Purpose of the Study:

• To rigorously test thermodynamic theories of the glass transition, specifically the Adam-Gibbs relation.
• To investigate the relationship between configurational entropy and the static point-to-set lengthscale.
• To compare simulation results with experimental data for supercooled molecular liquids.

Main Methods:

• Utilizing the swap Monte Carlo algorithm to calculate configurational entropy and the point-to-set lengthscale.
• Employing careful extrapolations to determine relaxation times.
• Analyzing both simulated glass-formers and experimental data from supercooled molecular liquids.

Main Results:

• The Adam-Gibbs relation is generally violated within the experimentally relevant time window for simulated models.
• A strong correlation is observed between configurational entropy and the point-to-set lengthscale in both 2D and 3D systems.
• Experimental data from supercooled molecular liquids exhibit similar deviations from the Adam-Gibbs relation.

Conclusions:

• Deviations from the Adam-Gibbs relation are consistent with random first-order transition theory.
• These deviations may reconcile discrepancies between Kauzmann and Vogel-Fulcher-Tammann temperatures.
• The findings suggest that factors beyond thermodynamics might drive slow dynamics near the glass transition temperature (Tg).