Figure 4

The influence of Coulomb interactions on the spectra of 〈 n _{2 s} 〉. The relevant parameters are taken to be V₁ = 0.5, V₂ = 0.1, and $\varphi =\frac{\Pi }{2}$. (a) The spectrum of 〈n_2s〉 vs ϵ₁ and ϵ₂. The Coulomb interactions are taken to be U₁ = U₂ = 1.0. (b) The spectrum of 〈n_2s〉 with U₁ = 3.0 and U₂ = 1.0. (c) The curve of 〈n_2s〉 vs ϵ₂ with U₁ = U₂ = 3.0. The level of QD-1 is taken to be ϵ₁ = 0 and ±0.5, respectively.