Mean-field caging in a random Lorentz gas

TL;DR

This paper investigates the mean-field behavior of the random Lorentz gas in high dimensions, revealing limitations of current theories and clarifying the nature of the localization transition related to glassy dynamics.

Contribution

It provides a detailed analysis of the $d ightarrowty$ limit of the RLG, comparing static and dynamical solutions with numerical and mode-coupling theory results, highlighting the challenges in theoretical descriptions.

Findings

Perturbative $1/d$ corrections are difficult to compute accurately.

Mode-coupling theory captures the discontinuous transition but lacks quantitative accuracy.

Finite-dimensional effects are crucial for understanding the localization transition.

Abstract

The random Lorentz gas (RLG) is a minimal model of both percolation and glassiness, which leads to a paradox in the infinite-dimensional, $d\rightarrow\infty$ limit: the localization transition is then expected to be continuous for the former and discontinuous for the latter. As a putative resolution, we have recently suggested that as $d$ increases the behavior of the RLG converges to the glassy description, and that percolation physics is recovered thanks to finite-$d$ perturbative and non-perturbative (instantonic) corrections [Biroli et al. arXiv:2003.11179]. Here, we expand on the $d\rightarrow\infty$ physics by considering a simpler static solution as well as the dynamical solution of the RLG. Comparing the $1/d$ correction of this solution with numerical results reveals that even perturbative corrections fall out of reach of existing theoretical descriptions. Comparing the dynamical solution with the mode-coupling theory (MCT) results further reveals that although key quantitative features of MCT are far off the mark, it does properly capture the discontinuous nature of the $d\rightarrow\infty$ RLG. These insights help chart a path toward a complete description of finite-dimensional glasses.