Show that when two identical detectors in an intensity interferometer have read noise with the same variance \(\sigma_{\text {read }}^{2}\) and when the average intensities incident on the two detectors are identical, the signal-to-noise ratio obtained in a single counting interval becomes

\[ \left(\frac{S}{N}\right)_{1}=\frac{\delta_{c} \mathcal{V}^{2}}{\sqrt{1+\frac{\sigma_{\text {read }}^{2}}{\bar{K}^{2}}}} \]