Fig. 5: Three- and four-copy collective measurements - experiments and simulation.
From: Discriminating mixed qubit states with collective measurements
The error probability is shown as a function of the noise scaling term, with the default noise parameters, corresponding to a scaling of 1, specified in the Simulation of two-copy collective measurement with noise section. The two states being discriminated are characterised by v = 0.1, α = π/4 and q = 0.75. The crosses correspond to the experimentally obtained error probabilities based on 200,000 shots, and the statistical error bars based on bootstrapping are smaller than the marker size. The horitzontal positioning of the experimental data points is of no physical significance. The solid horizontal lines show the theoretical limit given by the Helstrom bound for the corresponding number of copies (Pe,Col(ρ⊗M)).
