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arXiv · 1407.3917

Multiple higher-order singularities and iso-dynamics in a simple glass-former model

Nicoletta Gnan·Gayatri Das·Matthias Sperl·Francesco Sciortino·Emanuela Zaccarelli
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Abstract

We investigate the slow dynamics of a colloidal model with two repulsive length scales, whose interaction potential is the sum of a hard-core and a square shoulder. Despite the simplicity of the interactions, Mode-Coupling theory predicts a complex dynamic scenario: a fluid-glass line with two reentrances and a glass-glass line ending with multiple higher-order ($A_3$ or $A_4$) singularities. In this work we verify the existence of the two $A_4$ points by numerical simulations, observing subdiffusive behaviour of the mean-square displacement and logarithmic decay of the density correlators. Surprisingly, we also discover a novel dynamic behaviour generated by the competition between the two higher-order singularities. This results in the presence of special loci along which the dynamics is identical \textit{at all} length and time scales.

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Nicoletta Gnan, Gayatri Das, Matthias Sperl, Francesco Sciortino, Emanuela Zaccarelli. 2014-07-15. Multiple higher-order singularities and iso-dynamics in a simple glass-former model. https://arxiv.org/abs/1407.3917

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