Vanishing of configurational entropy may not imply an ideal glass transition in randomly pinned liquids

TL;DR

This study challenges the idea that vanishing configurational entropy necessarily indicates an ideal glass transition, showing through simulations that relaxation times remain finite even when entropy approaches zero.

Contribution

The paper provides evidence that vanishing configurational entropy does not always correspond to an ideal glass transition, contrasting previous theoretical assumptions.

Findings

Relaxation times remain finite at zero configurational entropy.

Simulation results contradict the notion of an inevitable ideal glass transition.

Supports previous findings that entropy vanishing does not imply diverging relaxation times.

Abstract

Ozawa et. al [1] presented numerical results for the configurational entropy density, $s_c$, of a model glass-forming liquid in the presence of random pinning. The location of a "phase boundary" in the pin density ($c$) - temperature ($T$) plane, that separates an "ideal glass" phase from the supercooled liquid phase, is obtained by finding the points at which $s_c(T,c) \to 0$. According to the theoretical arguments by Cammarota et. al. [2], an ideal glass transition at which the $\alpha$-relaxation time $\tau_\alpha$ diverges takes place when $s_c$ goes to zero. We have studied the dynamics of the same system using molecular dynamics simulations. We have calculated the time-dependence of the self intermediate scattering function, $F_s(k,t)$ at three state points in the $(c-T)$ plane where $s_c(T,c) \simeq 0$ according to Ref. [1]. It is clear from the plots that the relaxation time is finite [$\tau_\alpha \sim \mathcal{O}(10^6)]$ at these state points. Similar conclusions have been obtained in Ref.[3] where an overlap function was used to calculate $\tau_\alpha$ at these state points.