“…Motivated by the analysis of pure dephasing channels in [29,30], we choose the initial probe states of the polarization system as ρ 1 = ρ 2 = ρ 3 = |+ +|. After the polarization has interacted with the frequency for an unknown time, we perform tomographic measurements on the evolved states Φ 1 (ρ 1 ), Φ 2 (ρ 2 ), and Φ 3 (ρ 3 ) and calculate the α-fidelities F α Φ 1 (ρ 1 ), Φ 2 (ρ 2 ) and F α Φ 1 (ρ 1 ), Φ 3 (ρ 3 ) .…”