An analytical variational method for the biased quantum Rabi model in the ultra-strong coupling regime

Mao Bin-Bin¹, Liu Maoxin², Wu Wei², Li Liangsheng³, Ying Zu-Jian⁴, Luo Hong-Gang^{1, 2, †}

(color online) The mean photon number and correlation for different parameters: (a), (b) , Ω = 5, (c), (d) , g = 0.1, (e), (f) g = 0.2, Ω = 0.1.