Advantages of additional ancillary vacua and adaptive stages

Determine whether adding ancillary vacuum states and additional adaptive stages to the local Gaussian discrimination protocol for two-mode squeezed vacuum states improves the success-probability–fidelity tradeoff.

Background

The numerical analysis suggests that the locally squeezed protocol saturates the GLOCC₁ bound for the considered configuration. The authors conjecture that enlarging the protocol with additional ancillary vacuum states and adaptive stages may yield modest improvements, but they do not establish whether such improvements are possible.