Critical slowing down in thermal soft-sphere glasses via energy minimization

Abstract

Using hybrid molecular dynamics/SWAP Monte Carlo (MD/SMC) simulations, we show that the terminal relaxation times $\tau$ for FIRE energy minimization of soft-sphere glasses exhibit thermal onset as samples become increasingly well-equilibrated. Although $\tau (\varphi )$ can decrease by orders of magnitude as equilibration proceeds and the jamming density ${\varphi }_{\mathrm{J}}$ increases via thermal onset, it always scales as $\tau (\varphi )\sim ({\varphi }_{\mathrm{J}}-\varphi {)}^{-2}\sim [Z_{\mathrm{iso}}-Z_{\mathrm{ms}}(\tau ){]}^{-2}$, where ${\varphi }_{\mathrm{J}}$ is the jamming density and $Z_{\mathrm{ms}}(\tau )$ is the average coordination number of particles satisfying a minimal local mechanical stability criterion ($Z\ge d+1$) at the top of the final potential-energy-landscape (PEL) sub-basin the system encounters. This scaling allows us to collapse $\tau$ datasets that look very different when plotted as a function of $\varphi$, and to address a closely related question: how does the character of the PEL basins that dense thermal glasses most typically occupy evolve as the glasses age at constant $\varphi$ and $T$?

resubmitted in response to referee comments