Fig. 4: Trace verification for the DEMESST sampling method.

Trace versus point number for prepared (a) 2-mode, (b) 3-mode, and (c) 4-mode W states. Error bars are shown for every fourth point, as well as the final one, and indicate the standard error. They are obtained from comparing the traces from individual sets of measurements. As expected, the traces converge to values near unity. d Trace versus point number when measuring only a 2-mode subspace of a prepared 4-mode W state. Due to only measuring half of the populated space, the trace converges to 0.5. This demonstrates that the DEMESST sampling method is self-consistent and does not depend on the chosen measurement subspace.