Local optimality of a coherent feedback scheme for distributed entanglement generation: the idealized infinite bandwidth limit
For quantum information researchers, this provides a theoretical justification for the optimality of a specific entanglement generation scheme, though limited to an idealized infinite bandwidth scenario.
The paper proves a local optimality property of a coherent feedback scheme for distributed EPR entanglement generation using two NOPAs in the infinite bandwidth limit, showing it outperforms other similar configurations with different scattering matrices.
The purpose of this paper is to prove a local optimality property of a recently proposed coherent feedback configuration for distributed generation of EPR entanglement using two nondegenerate optical parametric amplifiers (NOPAs) in the idealized infinite bandwidth limit. This local optimality is with respect to a class of similar coherent feedback configurations but employing different unitary scattering matrices, representing different scattering of propagating signals within the network. The infinite bandwidth limit is considered as it significantly simplifies the analysis, allowing local optimality criteria to be explicitly verified. Nonetheless, this limit is relevant for the finite bandwidth scenario as it provides an accurate approximation to the EPR entanglement in the low frequency region where EPR entanglement exists.