Self-Referential Order

TL;DR

This paper introduces the concept of self-referential order to quantify structural organization in disordered materials, using an information-theoretic approach and motifs to efficiently describe complex structures.

Contribution

It presents a novel method to measure and encode disorder in materials through self-referential motifs and an entropic order parameter, applicable to non-crystalline systems.

Findings

Defined a self-referential-order-parameter using entropic measures

Demonstrated the method on equal disk packing

Showed reduction of structural information via motifs

Abstract

We introduce the concept of {\it self-referential order} which provides a way to quantify structural organization in non crystalline materials. The key idea consists in the observation that, in a disordered system, where there is no ideal, reference, template structure, each sub-portion of the whole structure can be taken as reference for the rest and the system can be described in terms of its parts in a self-referential way. Some of the parts carry larger information about the rest of the structure and they are identified as {\it motifs}. We discuss how this method can efficiently reduce the amount of information required to describe a complex disordered structure by encoding it in a set of motifs and {\it matching rules}. We propose an information-theoretic approach to define a {\it self-referential-order-parameter} and we show that, by means of entropic measures, such a parameter can be quantified explicitly. A proof of concept application to equal disk packing is presented and discussed.