Figure 6

The initial second-order correlation,${\mathit{g}}_{\mathbf{2}}\mathbf{(}\mathbf{0}\mathbf{)}$(on a logarithmic scale), calculated with a weak incident coherent state as a function of the frequency ω near the qubit resonant frequency (${\mathit{\omega }}_{\mathbf{0}}\mathbf{=}\mathbf{100}\mathbf{\Gamma }$) for different numbers of qubits. The first (second) row is for $k_{0}L=\pi /2$ ($\pi /4$); the first (second) column is for transmitted (reflected) photons. The black, dashed line indicates the classical value (i.e., $g_2=1$). For reflected photons with $N=1$, $g_2(0)=0$ for all ω and hence is not plotted. Note that as for the single-photon transmission in Fig. 2, $g_2(0)$ is symmetric about ${\omega }_0$ for $k_{0}L=\pi /2$ but asymmetric in the $k_{0}L=\pi /4$ case. For a wide range of parameters, both transmitted and reflected photons are bunched.