Quadripartite quantum steering generated by single-pass cascaded nonlinear processes

Abstract

Quantum steering has become an important resource for quantum information due to its unique asymmetry. In this paper, quadripartite quantum steering generated by single-pass non-degenerate optical parametric amplification cascaded with a sum-frequency process is investigated. Firstly, idler beam is produced by different-frequency process between pump and signal. Secondly, sum-frequency beam is generated by cascaded sum-frequency process between idler and pump in the same optical superlattice. Quadripartite quantum steering among pump, signal, idler and sum-frequency beams id demonstrated based on the criterion for multipartite quantum steering. The influences of nonlinear coupling coefficients $\kappa$, dimensionless propagation length $\xi$, and the initial values of pump and signal on the variation characteristic of the quadripartite steering are also investigated. The results indicate that slightly larger nonlinear coupling coefficients of cascaded nonlinear processes and weaker signals can achieve better quadripartite quantum steering. This simple quadripartite quantum steering preparation scheme does not require a resonant cavity and is easier to implement experimentally, with potential applications in quantum communication and computing.