Scalable continuous-variable entanglement of light beams produced by optical parametric oscillators

TL;DR

This paper demonstrates that optical parametric oscillators can generate scalable multipartite entanglement among light beams, enabling the development of continuous-variable quantum networks with adjustable entanglement distribution.

Contribution

It introduces a method to produce scalable multipartite entanglement using cascaded OPOs, extending entanglement from three beams to many, with tunable distribution.

Findings

Tripartite entanglement among pump, signal, and idler beams in a single OPO.

Scalable entanglement among multiple OPOs via a common optical pump.

Manipulation of entanglement structure by adjusting pump power.

Abstract

We show that scalable multipartite entanglement among light fields may be generated by optical parametric oscillators (OPO). The tripartite entanglement existent among the three bright beams produced by a single OPO -- pump, signal, and idler -- is scalable to a system of many OPOs by pumping them in cascade with the same optical field. This latter serves as an entanglement distributor. The special case of two OPOs is studied, as it is shown that the resulting five bright beams share genuine multipartite entanglement. In addition, the structure of entanglement distribution among the fields can be manipulated to some degree by tuning the incident pump power. The scalability to many fields is straightforward, allowing an alternative implementation of a multipartite quantum information network with continuous variables.