Reinterpreting ultrafast experiments on supercooled water: Glass transition versus liquid-liquid criticality
Abstract
Water's anomalous properties have been hypothesized to originate from a liquid-liquid critical point in the supercooled regime, separating high- and low-density liquid states. Experimental verification remains challenging due to rapid crystallization under these conditions. A recent study reported evidence for such a transition, based primarily on a pronounced increase in the heat capacity of rapidly heated low-density amorphous ice. Here, we show that this heat capacity increase can be explained without invoking a liquid-liquid transition. By combining simulations using a machine-learning potential trained on the state-of-the-art MB-pol water model, combined with the Tool-Narayanaswamy-Moynihan (TNM) model of the glass transition, we demonstrate that the observed signal can arise instead from a dynamical effect induced by the mobilization of rotational and translational molecular degrees of freedom during ultrafast heating. We further show that our findings are fully consistent with recent electron diffraction measurements showing structural arrest of supercooled water close to our predicted glass-transition temperature. These results provide an alternative interpretation of the experimental observations and highlight the importance of nonequilibrium glassy dynamics in the interpretation of the behavior of supercooled water on ultra-short time scales.
Related
- Activation force dependence of the fluidization transition in supercooled active water
- Replica Transition at Measurement-Altered Ising Criticality
- Criticality and Quench Dynamics at the Anderson Transition of a Chern Insulator
- Quantum Ising transition on the Cayley tree: boundary criticality, universality, and an effective Bethe line
- Beyond RMSD: Deterministic Dlow Matching for Ultrafast and Physically Validated Transition-State Generation
BibTeX
@misc{pabst2026reinterpreting,
title = {{Reinterpreting ultrafast experiments on supercooled water: Glass transition versus liquid-liquid criticality}},
author = {Florian Pabst and Ali Hassanali},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.26442},
eprint = {2609.26442},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.26442},
note = {CC BY-SA 4.0},
}
RIS
TY - UNPB
TI - Reinterpreting ultrafast experiments on supercooled water: Glass transition versus liquid-liquid criticality
AU - Florian Pabst
AU - Ali Hassanali
PY - 2026
DA - 2026/09/22
PB - arXiv
DO - 10.48550/arxiv.2609.26442
UR - https://arxiv.org/abs/2609.26442
AB - Water's anomalous properties have been hypothesized to originate from a liquid-liquid critical point in the supercooled regime, separating high- and low-density liquid states. Experimental verification remains challenging due to rapid crystallization under these conditions. A recent study reported evidence for such a transition, based primarily on a pronounced increase in the heat capacity of rapidly heated low-density amorphous ice. Here, we show that this heat capacity increase can be explained without invoking a liquid-liquid transition. By combining simulations using a machine-learning potential trained on the state-of-the-art MB-pol water model, combined with the Tool-Narayanaswamy-Moynihan (TNM) model of the glass transition, we demonstrate that the observed signal can arise instead from a dynamical effect induced by the mobilization of rotational and translational molecular degrees of freedom during ultrafast heating. We further show that our findings are fully consistent with recent electron diffraction measurements showing structural arrest of supercooled water close to our predicted glass-transition temperature. These results provide an alternative interpretation of the experimental observations and highlight the importance of nonequilibrium glassy dynamics in the interpretation of the behavior of supercooled water on ultra-short time scales.
ER -