Comparative study of nonclassicality, entanglement, and dimensionality of multimode noisy twin beams

TL;DR

This paper compares nonclassicality, entanglement, and dimensionality in noisy twin beams, revealing their interrelations and how noise affects their quantum properties using characteristic functions and participation ratios.

Contribution

It introduces a detailed analysis of the relationship between nonclassicality, entanglement, and dimensionality in multimode noisy twin beams, including a partitioning of degrees of freedom.

Findings

Negativity correlates with nonclassicality depth.

Entanglement and nonclassicality are limited by noise levels.

Dimensionality measures differ for entanglement and noise effects.

Abstract

Nonclassicality, entanglement, as well as dimensionality of a noisy twin beam are determined using characteristic function of the beam written in the Fock basis. One-to-one correspondence between the negativity quantifying entanglement and the nonclassicality depth is revealed. Twin beams, which are either entangled or nonclassical (independent of their entanglement), are observed only for the limited degrees of noise that degrades their quantumness. Dimensionality of the twin beam quantified by the participation ratio is compared with the dimensionality of entanglement determined from the negativity. The partition of the degrees of freedom of the twin beam into those related to entanglement and to noise is suggested. Both single-mode and multimode twin beams are analyzed. Weak nonclassicality based on integrated-intensity quasidistributions of multimode twin beams is studied. Relation of the model to the experimental twin beams is discussed.