Order indices of density matrices for finite systems

TL;DR

This paper extends the concept of order indices to finite quantum systems, enabling the characterization of their ordering levels, with explicit calculations for bosonic atoms in a finite box at zero temperature.

Contribution

It introduces a generalized theory of order indices applicable to finite systems and demonstrates it through explicit calculations for bosonic atoms.

Findings

Order indices can characterize ordering in finite quantum systems.

Explicit calculation of order index for bosonic atoms in a finite box.

The theory applies to systems like macromolecules and quantum dots.

Abstract

The definition of order indices for density matrices is extended to finite systems. This makes it possible to characterize the level of ordering in such finite systems as macromolecules, nanoclusters, quantum dots, or trapped atoms. The general theory is exemplified by explicit calculations of the order index for the first-order density matrix of bosonic atoms confined in a finite box at zero temperature.