Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · cond-mat/0606459

Phase transition in a static granular system

Matthias Schröter·Sibylle Nägle·Charles Radin·Harry L. Swinney
View original source ↗Read source document ↗Export metadata ↓

Abstract

We find that a column of glass beads exhibits a well-defined transition between two phases that differ in their resistance to shear. Pulses of fluidization are used to prepare static states with well-defined particle volume fractions $ϕ$ in the range 0.57-0.63. The resistance to shear is determined by slowly inserting a rod into the column of beads. The transition occurs at $ϕ=0.60$ for a range of speeds of the rod.

Explore related subjects

cond-mat.soft

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Matthias Schröter, Sibylle Nägle, Charles Radin, Harry L. Swinney. 2006-10-03. Phase transition in a static granular system. https://doi.org/10.1209/0295-5075%2F78%2F44004

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Improved Density Functionals for Predicting Block Copolymer Domain Structure and Phase Behavior

Phase-field models offer an efficient alternative to self-consistent field theory (SCFT), but quantitative predictions of block-copolymer phase behavior remain challenging. We develop a quadratic-connectivity entropic (QCE) density functional and its adaptive extension (AQCE). QCE combines quadratic nonlocal connectivity with a nonlinear binary relative-entropy term, while AQCE adds bounded interfacial stiffness that preserves the homogeneous response. In lamellar benchmarks, QCE gives the lowest mean profile error among the tested models and AQCE the lowest mean period error. Compared with the optimized phase-field (OPF) model fitted to SCFT force and stress data, AQCE reduces strong-segregation period and profile errors by more than fivefold and sixfold, respectively. AQCE further reproduces the topology of the SCFT phase diagram for AB diblocks, a more demanding test of free-energy rankings among competing morphologies. Because architecture enters through ideal-chain correlations, the same nonlinear construction extends to other A/B architectures. We demonstrate this transfer for symmetric linear ABA lamellae, accurately predicting their profiles, periods, and ordering threshold.

cond-mat.soft↗
arXiv2026

Efficient Searches for Low-Energy Structures in Clusters with Thousands of Particles: Application to the Thomson Problem

We propose an algorithm for identifying low-energy minima in systems containing thousands of particles, at moderate computational cost. We focus on spherical crystals, in which particles form ordered structures on the surface of a sphere. Our method uses symmetric seed configurations, or known structures, to initialize searches across contiguous ranges of system sizes. Newly identified minima are then used to guide searches at neighbouring sizes, allowing information to propagate efficiently through configuration space. We have tested this approach on the Thomson problem, one of the few interacting-particle systems for which global optimization has been considered for systems of this size. We substantially improve on many previous solutions, particularly at larger system sizes, where systematic global optimization is computationally expensive. Since favourable packings for the Thomson problem are reflected in systems spanning atomistic to mesoscopic length scales, the newly characterized defect patterns may inform structure prediction for a broad range of problems with spherical topology.

cond-mat.soft↗
arXiv2026

Fluctuating chemically active droplets

We study size fluctuations of chemically active droplets in the regime of weak reactions and strong phase separation. By combining a thin-interface model for the deterministic droplet growth with stochastic noise based on fluctuation-dissipation arguments, we report excellent quantitative agreement between our theory and numerical field simulations. Finally, we use our model to infer the effective non-equilibrium potential that governs droplet growth, and show that active reactions that enable size control suppress nucleation.

cond-mat.soft↗