Glassy dynamics of a binary Voronoi fluid: a mode-coupling analysis.

Area of Science:

• Computational physics and chemistry
• Soft matter physics
• Statistical mechanics

Background:

• The binary Voronoi mixture is a novel fluid model featuring local, many-body interactions derived from Voronoi-Laguerre tessellation.
• Understanding the dynamics of supercooled liquids is crucial for materials science and condensed matter physics.

Purpose of the Study:

• To investigate the structural relaxation dynamics of a weakly polydisperse, additive binary Voronoi mixture in the supercooled-liquid regime.
• To compare simulation results with first-principles-based idealized mode-coupling theory (MCT) for validation and predictive power assessment.

Main Methods:

• Performed molecular-dynamics (MD) simulations of the binary Voronoi mixture.
• Calculated time- and temperature-dependent coherent and incoherent scattering functions and mean-square displacements.
• Compared MD results with MCT using two approaches: fitting asymptotic predictions and using static-structure-factor input for parameter-free calculations.

Main Results:

• Many-body interactions in the Voronoi mixture showed no strong qualitative differences in dynamics compared to simple liquids with pair-wise interactions.
• Fitted exponent parameter (λ ≈ 0.746) and Kohlrausch relaxation time behavior were consistent with literature for similar systems.
• Mode-coupling theory (MCT) calculations based on static input showed a modest overestimation of the critical temperature (factor of ~1.2).

Conclusions:

• The study demonstrates that many-body interactions in the Voronoi mixture do not qualitatively alter supercooled-liquid dynamics.
• There is strong agreement between MD simulations and MCT, suggesting predictive capabilities of MCT based solely on static correlations.
• This highlights the potential to predict microscopic dynamic properties of complex fluids using static structural information, even with inherent many-body interactions.