Bidirectional transfer of quantum information for unknown photons via cross-Kerr nonlinearity and photon-number-resolving measurement

Heo Jino^{1, 2}, Hong Chang-Ho^{1, 2}, Lee Dong-Hoon^{1, 2}, Yang Hyung-Jin^{1, 3, †,}

Plots of the error probabilities of the C-path gates based on coherent state and X-homodyne (red line(upper)),^[23] CSS and P-homodyne (black curve (middle)),^[27] and the qubus beams and the QND (PNR) detection (blue curve (lower)), each as a function of θ (the XKNL’s phase shift), for probe beam amplitude α = 1000. The red (upper), black (middle), and blue (lower) plots are the functions of and respectively, as indicated in Eq. (19). For example, when θ = 0.003 and α = 1000, the error probabilities are , and .