Freezing in the Infinite-Bin Model
Bastien Mallein, Sanjay Ramassamy, Arvind Singh
TL;DR
This work analyzes freezing in the infinite-bin model (IBM), a ranked, memoryful, one-dimensional particle system driven by a reproduction law $\mu$. It develops a comprehensive framework combining genealogical structure and coupling techniques to derive when bins receive only finitely many balls in the infinite-time limit, i.e., freezing, and to establish a 0-1 law for freezing under monotone $\mu$. It shows that bounded or locally finite initial configurations typically lead to almost sure freezing, while infinite-type $\mu$ can sustain non-freezing cascades, with a clear dependency on the type. In the barrier-at-zero setting with regularly varying $\mu$, the paper provides precise dichotomies for freezing and derives explicit deterministic growth rates for the barrier-driven growth, highlighting how tail behavior of $\mu$ controls long-time dynamics. Overall, the results yield concrete criteria to predict freezing versus unbounded growth in rank-based, memory-rich branching systems, with explicit growth-rate formulas in the barrier regime.
Abstract
The infinite-bin model is a one-dimensional particle system on $\mathbb{Z}$ introduced by Foss and Konstantopoulos in relation with last passage percolation on complete directed acyclic graphs. In this model, at each integer time, a particle is selected at random according to its rank, and produces a child at the location immediately to its right. In this article, we consider the limiting distribution of particles after an infinite number of branching events have occurred. Under mild assumptions, we prove that the event (called freezing) that a location contains only a finite number of balls satisfies a $0-1$ law and we provide various criteria to determine whether freezing occurs.
