Figure 2: Hong-Ou-Mandel effect for a |1, 1, 1› input state in an ideal tritter.
From: Three-photon bosonic coalescence in an integrated tritter
Theoretical output probabilities P1,1,1 (a), P2,1,0 (b), and P3,0,0 (c) as a function of the delays xi=c τi of the impinging photons. (d–f) Theoretical output probabilities 
for three indistinguishable input photons, 
for three photons out of interference and 
for two indistinguishable and one delayed input photons. The red bars take into account the presence of partial distinguishability between the three impinging photons with indistinguishability p=0.65 whereas blue bars refer to perfectly indistinguishable photons with p=1 (see Supplementary Note 4). The dashed horizontal lines represent the classical boundaries.
