Fig. 4: NV trilateration results.
From: A variational toolbox for quantum multi-parameter estimation
Semi-logarithmic plot of the weighted Cramér-Rao bound for NV trilateration over the gate depolarization probability of (blue) local probes and (orange) shallow entangled probes. Each dot marks the bound for a probe optimized for the particular gate depolarization probability. The measurement is always local. The inset shows the positions of the NV centers and the target spin used in the experiment. The entangling operations only yield an advantage for vanishing gate noise.
