Quenched localisation in the Bouchaud trap model with slowly varying traps

TL;DR

This paper demonstrates that in the Bouchaud trap model with slowly varying trap distributions, the number of localized sites can be precisely controlled and tuned to any integer value, revealing new insights into localization phenomena.

Contribution

It introduces a novel example where the exact number of localization sites in the Bouchaud trap model can be tuned by adjusting the trap distribution's tail behavior.

Findings

Localization occurs on exactly N sites for each N ≥ 2.

The model allows tuning the number of localization sites.

Sum-max ratio behavior provides key intuition.

Abstract

We consider the quenched localisation of the Bouchaud trap model on the positive integers in the case that the trap distribution has a slowly varying tail at infinity. Our main result is that for each $N \in \{2, 3, \ldots\}$ there exists a slowly varying tail such that quenched localisation occurs on exactly $N$ sites. As far as we are aware, this is the first example of a model in which the exact number of localisation sites are able to be `tuned' according to the model parameters. Key intuition for this result is provided by an observation about the sum-max ratio for sequences of independent and identically distributed random variables with a slowly varying distributional tail, which is of independent interest.