Pinch-point Singularities in Stress-Stress Correlations Reveal Rigidity in Colloidal Gels

Fuente: arXiv
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Autores principales: Countryman, Albert, Vinutha, H. A., Ruiz, Fabiola Diaz, Mao, Xiaoming, Del Gado, Emanuela, Chakraborty, Bulbul
Formato: Preprint
Publicado: 2025
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author Countryman, Albert
Vinutha, H. A.
Ruiz, Fabiola Diaz
Mao, Xiaoming
Del Gado, Emanuela
Chakraborty, Bulbul
author_facet Countryman, Albert
Vinutha, H. A.
Ruiz, Fabiola Diaz
Mao, Xiaoming
Del Gado, Emanuela
Chakraborty, Bulbul
contents We demonstrate that the spatial correlations of microscopic stresses in 2D model colloidal gels obtained in computer simulations can be quantitatively described by the predictions of a theory for emergent elasticity of pre-stressed solids (vector charge theory). By combining a rigidity analysis with the characterization provided by the stress correlations, we show that the theoretical predictions are able to distinguish rigid from floppy gels, and quantify that distinction in terms of the size of a pinch-point singularity emerging at large length scales, which, in the theory, directly derives from the constraints imposed by mechanical equilibrium on the internal forces. We also use the theoretical predictions to investigate the coupling between stress-transmission and rigidity, and we explore the possibility of a Debye-like screening mechanism that would modify the theory predictions below a characteristic length scale.
format Preprint
id arxiv_https___arxiv_org_abs_2502_18796
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Pinch-point Singularities in Stress-Stress Correlations Reveal Rigidity in Colloidal Gels
Countryman, Albert
Vinutha, H. A.
Ruiz, Fabiola Diaz
Mao, Xiaoming
Del Gado, Emanuela
Chakraborty, Bulbul
Soft Condensed Matter
We demonstrate that the spatial correlations of microscopic stresses in 2D model colloidal gels obtained in computer simulations can be quantitatively described by the predictions of a theory for emergent elasticity of pre-stressed solids (vector charge theory). By combining a rigidity analysis with the characterization provided by the stress correlations, we show that the theoretical predictions are able to distinguish rigid from floppy gels, and quantify that distinction in terms of the size of a pinch-point singularity emerging at large length scales, which, in the theory, directly derives from the constraints imposed by mechanical equilibrium on the internal forces. We also use the theoretical predictions to investigate the coupling between stress-transmission and rigidity, and we explore the possibility of a Debye-like screening mechanism that would modify the theory predictions below a characteristic length scale.
title Pinch-point Singularities in Stress-Stress Correlations Reveal Rigidity in Colloidal Gels
topic Soft Condensed Matter
url https://arxiv.org/abs/2502.18796