Quantum Correlations in Three-Beam Symmetric Gaussian States Accessed via Photon-Number-Resolving Detection and Quantum Universal Invariants

TL;DR

This paper investigates quantum correlations in three-beam symmetric Gaussian states using quantum invariants derived from intensity moments, experimentally generating and analyzing states with varying noise levels to observe different entanglement types.

Contribution

It introduces a method to analyze quantum correlations in Gaussian states via quantum universal invariants and experimentally verifies entanglement properties in noisy states.

Findings

Coexistence of bi- and tripartite entanglement observed.

Genuine tripartite entanglement identified in noisy states.

Quantum invariants effectively quantify correlations.

Abstract

Quantum correlations of 3-beam symmetric Gaussian states are analyzed using their quantum universal invariants. These invariants, 1-, 2-, and 3-beam purities, are expressed in terms of the beams' intensity moments up to sixth order. The 3-beam symmetric Gaussian states with varying amounts of the noise are experimentally generated using entangled photon pairs from down-conversion, their invariants are determined, and their quantum correlations are quantified. The coexistence of bi- and tripartite entanglement and genuine tripartite entanglement are observed in these states that resemble the noisy GHZ/W states.