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DY: Fachverband Dynamik und Statistische Physik

DY 23: Complex Fluids and Soft Matter (joint session DY/CPP)

DY 23.10: Talk

Tuesday, March 10, 2026, 12:00–12:15, ZEU/0160

Random close packing as a conserved directed percolation transition — •Thomas Axmann and Michael Schmiedeberg — Theoretical Physics: Lab for Emergent Phenomena, Soft Matter Theory Group, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany

In studying quenches in soft sphere systems O’Hern et al. related the onset of overlaps to isostaticity [1], and consequently to the random close packing scenario. The conditions that lead to the avoidance of overlaps between spheres can be studied with the random organization model [2], which was initially introduced to investigate self organization in sheared colloids. Modifications of this model, which dynamically reduce interparticle overlaps, were used to characterize the random close packing problem as the critical point of a dynamic absorbing state transition in the d+1 dimensional conserved directed percolation universality [3,4].

We aim to deepen the understanding of this connection by demonstrating that the configuration change at each time step can be chosen with a fully deterministic strategy while retaining the features of the transition. We clarify difficulties in the treatment of percolating clusters and find that the median overlap depth proves to be a more useful order parameter.

[1] O’Hern et al. PRE 68 (2003)

[2] Corté et al. Nat. Phys. 4 (2008)

[3] Milz et al. PRE 88 (2013)

[4] Wilken et al. PRE 128 (2021)

Keywords: Dynamical Phase Transition; Jamming; Random Organization