Configurational entropy and Adam-Gibbs relation for quantum liquids.

Zhou, Yang; Eltareb, Ali; Lopez, Gustavo E; Giovambattista, Nicolas · Nat Commun · 2026

basic_science · Level V

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Abstract

As a liquid approaches the glass state, its dynamics slows down rapidly, by a few orders of magnitude in a very small temperature range. In the case of light elements and small molecules containing hydrogen (e.g., water), such a process can be affected by nuclear quantum effects (due to quantum fluctuations/atoms delocalization). In this work, we apply the potential energy landscape (PEL) formalism and path-integral computer simulations to study the low-temperature behavior of a Lennard-Jones binary mixture (LJBM) that obeys quantum mechanics. We show that, as for the case of classical liquids, (i) a configurational entropy S<sub>IS</sub> can be defined, and (ii) the Adam-Gibbs equation, which relates the diffusion coefficient of a liquid and its S<sub>IS</sub>, holds for the studied quantum LJBM. Overall, this study shows that one theoretical approach, the PEL formalism, can be used to describe low-temperature liquids close to their glass transition, independently of whether the system obeys classical or quantum mechanics.