# Slow dynamics coupled with cluster formation in ultrasoft-potential glasses

## TL;DR

This study explores how ultrasoft particles form clusters and exhibit slow, glassy dynamics, revealing multiple cluster-glass phases and anomalous relaxation behaviors near phase boundaries.

## Contribution

It uncovers multiple cluster-glass phases and anomalous relaxation phenomena in ultrasoft particle mixtures, advancing understanding of complex glassy states.

## Key findings

- Multiple cluster-glass phases with distinct cluster sizes
- Logarithmic slow relaxation near phase boundaries
- Decoupling of single-particle and collective dynamics in deep glass phases

## Abstract

We numerically investigate slow dynamics of a binary mixture of ultrasoft particles interacting with the generalized Hertzian potential. If the softness parameter, $\alpha$, is small, the particles at high densities start penetrating each other, form clusters, and eventually undergo the glass transition. We find multiple cluster-glass phases characterized by different number of particles per cluster, whose boundary lines are sharply separated by the cluster size. Anomalous logarithmic slow relaxation of the density correlation functions is observed in the vicinity of these glass-glass phase boundaries, which hints the existence of the higher-order dynamical singularities predicted by the mode-coupling theory. Deeply in the cluster glass phases, it is found that the dynamics of a single particle is decoupled from that of the collective fluctuations.