Spectral Analysis of a Four Mode Cluster State

TL;DR

This paper provides a theoretical analysis of the squeezing properties of a quadripartite entangled state generated by a single optical parametric oscillator, expanding understanding of its quantum correlations.

Contribution

It offers a detailed linearized fluctuation analysis of the joint quadrature squeezing in a four-mode cluster state, complementing previous experimental work.

Findings

Squeezing of joint quadrature operators below threshold is characterized.

Optimal local oscillator phases and frequencies for maximum squeezing are identified.

Theoretical results support the potential of this system for quantum information applications.

Abstract

We theoretically evaluate the squeezed joint operators produced in a single optical parametric oscillator which generates quadripartite entangled outputs, as demonstrated experimentally by Pysher et al. \cite{pysher}[Phys. Rev. Lett. 107, 030505 (2011)]. Using a linearized fluctuation analysis we calculate the squeezing of the joint quadrature operators below threshold for a range of local oscillator phases and frequencies. These results add to the existing theoretical understanding of this potentially important system.