Analysis of the anomalous mean field like properties of Gaussian core model in terms of entropy

Abstract

Studies of the Gaussian core model (GCM) have shown that it behaves like a mean field model and the properties are quite different from standard glass former. In this work we investigate the entropies, namely the excess entropy ($S_{ex}$) and the configurational entropy ($S_c$) and their different components to address these anomalies. Our study corroborates most of the earlier observations and also sheds new light on the high and low temperature dynamics. We find that unlike in standard glass former where high temperature dynamics is dominated by two body correlation and low temperature by many body correlations, in GCM both high and low temperature dynamics are dominated by many body correlations. We also find that the many body entropy which is usually positive at low temperatures and is associated with activated dynamics is negative in GCM suggesting suppression of activation. Interestingly despite suppression of activation the Adam-Gibbs (AG) relation which describes activated dynamics holds in GCM, thus suggesting a non-activated contribution in AG relation. We also find an overlap between the AG and mode coupling power law regime leading to a power law behaviour of $S_c$. From our analysis of this power law behaviour we predict that in GCM the high temperature dynamics will disappear at dynamical transition temperature and below that there will be a transition to the activated regime. Our study further reveals that the activated regime in GCM is quite narrow.

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