Stress Response of Jammed Solids: Prestress and Screening

Fuente: arXiv
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Main Authors: Chakraborty, Surajit, Nampoothiri, Jishnu N., Bhattacharjee, Subhro, Chakraborty, Bulbul, Ramola, Kabir
Format: Preprint
Published: 2025
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author Chakraborty, Surajit
Nampoothiri, Jishnu N.
Bhattacharjee, Subhro
Chakraborty, Bulbul
Ramola, Kabir
author_facet Chakraborty, Surajit
Nampoothiri, Jishnu N.
Bhattacharjee, Subhro
Chakraborty, Bulbul
Ramola, Kabir
contents Unlike classical elasticity, where stresses arise from deformations relative to a stress-free reference configuration, rigidity in amorphous systems is maintained by disordered force networks that generate internal prestress. Previously, we introduced a ''stress-only'' formulation, where mechanical equilibrium resembles Gauss's law in a rank-2 tensor electrostatics with vector charges, and demonstrated that the mechanical response of jammed solids is described by the dielectric response of this gauge-theoretic formulation. Here, we extend this framework by incorporating scale-dependent screening that captures both dielectric and Debye-type behaviour. This introduces a characteristic length scale in stress correlations as well as in the response to external forces. Through numerical simulations of soft-sphere packings, we show that this length scale is set by the particle size, thus providing a natural ultraviolet cutoff while preserving long-wavelength emergent elasticity. We show that this lengthscale remains finite for all pressures, with no evidence for an emergent Debye-like screening near the frictionless unjamming transition. We demonstrate that although individual realisations show strong fluctuations, disorder averaging at fixed macroscopic conditions yields a robust dielectric-like response that persists up to unjamming. Finally, we also provide a physical interpretation of the gauge field within the electrostatic mapping: relative grain displacements in response to localised external perturbations correspond to difference in the gauge field, linking the field-theoretic description to particle-level mechanics.
format Preprint
id arxiv_https___arxiv_org_abs_2509_14336
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Stress Response of Jammed Solids: Prestress and Screening
Chakraborty, Surajit
Nampoothiri, Jishnu N.
Bhattacharjee, Subhro
Chakraborty, Bulbul
Ramola, Kabir
Soft Condensed Matter
Disordered Systems and Neural Networks
Statistical Mechanics
Unlike classical elasticity, where stresses arise from deformations relative to a stress-free reference configuration, rigidity in amorphous systems is maintained by disordered force networks that generate internal prestress. Previously, we introduced a ''stress-only'' formulation, where mechanical equilibrium resembles Gauss's law in a rank-2 tensor electrostatics with vector charges, and demonstrated that the mechanical response of jammed solids is described by the dielectric response of this gauge-theoretic formulation. Here, we extend this framework by incorporating scale-dependent screening that captures both dielectric and Debye-type behaviour. This introduces a characteristic length scale in stress correlations as well as in the response to external forces. Through numerical simulations of soft-sphere packings, we show that this length scale is set by the particle size, thus providing a natural ultraviolet cutoff while preserving long-wavelength emergent elasticity. We show that this lengthscale remains finite for all pressures, with no evidence for an emergent Debye-like screening near the frictionless unjamming transition. We demonstrate that although individual realisations show strong fluctuations, disorder averaging at fixed macroscopic conditions yields a robust dielectric-like response that persists up to unjamming. Finally, we also provide a physical interpretation of the gauge field within the electrostatic mapping: relative grain displacements in response to localised external perturbations correspond to difference in the gauge field, linking the field-theoretic description to particle-level mechanics.
title Stress Response of Jammed Solids: Prestress and Screening
topic Soft Condensed Matter
Disordered Systems and Neural Networks
Statistical Mechanics
url https://arxiv.org/abs/2509.14336