The logarithm of 〈a†a〉 to the base 10 as a function of ϕ₂+2nπ and the detuning. Panels (a) and (b) correspond to driving the cavity (η_a/κ = 0.5) and driving the atoms (η_c/κ = 0.5) correspond to panels (c) and (d). Panels (a) and (c) correspond to phase ϕ₁ = 2nπ. Panels (b) and (d) correspond to phase ϕ₁ = (2n+1/4)π. The white dashed line and black dashed lines correspond to eigen energy values in single photon space and in two-photon space, respectively. The other parameters are the same as those in Fig. 2.